Laser processing device

Abstract

A laser processing apparatus irradiates a portion of a focused area onto an object with a laser, thereby forming a modified region on the object. The laser processing apparatus includes: a support unit configured to rotate about a vertical axis and support the object; an irradiation unit that irradiates the object supported by the support unit with a laser beam polarized in a first horizontal direction; a first moving mechanism that moves the irradiation unit along the polarization direction, i.e., the first horizontal direction; a second moving mechanism that moves at least one of the support unit and the irradiation unit along a second horizontal direction perpendicular to the polarization direction; and a control unit that controls the operation of the support unit, the irradiation unit, the first moving mechanism, and the second moving mechanism.

Description

Technical Field

[0001] This invention relates to a laser processing apparatus. Background Technology

[0002] Laser processing apparatuses are known to focus a portion of a focal area onto an object to irradiate it with laser light, thereby forming a modified region on the object. As such a technology, Patent Document 1 describes a laser processing apparatus comprising: a holding mechanism for holding a workpiece, and a laser irradiation mechanism for irradiating the workpiece held by the holding mechanism with laser light. The laser processing apparatus described in Patent Document 1 fixes the laser irradiation mechanism, which has a focal lens, to a base, and moves the workpiece along a direction perpendicular to the optical axis of the focal lens via the holding mechanism.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 5456510 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The aforementioned laser processing apparatus moves a portion of the focusing area of ​​the laser irradiating the object relative to it, thereby forming a modified region on the object. In such a laser processing apparatus, for example, in order to achieve efficient laser processing, it is desirable to make the cracks easily extend from the modified region along the movement direction of a portion of the focusing area (hereinafter also referred to as the "processing travel direction").

[0008] Furthermore, the aforementioned laser processing apparatus is intended to be used for various laser processing operations, such as trimming processes that remove unwanted portions of an object's outer edges. However, to meet this requirement, the mechanism for moving a portion of the laser's focusing area would need to be large-scale, and there are even concerns about the overall size of the apparatus.

[0009] The object of the present invention is to provide a laser processing apparatus that can suppress the large size of the apparatus structure and make it easy for cracks to extend from the modified region along the direction of laser movement.

[0010] Technical means for solving problems

[0011] According to one aspect of the present invention, a laser processing apparatus is used to irradiate a target object with a laser beam, thereby forming a modified region on the target object. The laser processing apparatus includes: a support portion configured to rotate about an axis in the vertical direction and supporting the target object; an irradiation portion that irradiates the target object supported by the support portion with a laser beam polarized in a first horizontal direction; a first moving mechanism that moves the irradiation portion along the first horizontal direction along 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 perpendicular to the polarization direction; and a control portion that controls the operation of the support portion, the irradiation portion, the first moving mechanism, and the second moving mechanism.

[0012] The laser processing apparatus of one aspect of the present invention is configured to perform laser processing in which a support is rotated such that the tangential direction of the rotation becomes the polarization direction of the laser (hereinafter simply referred to as the "polarization direction"). Furthermore, laser processing in which a portion of the focusing region is linearly moved along the polarization direction is also possible. That is, various laser processing methods are possible, allowing the polarization direction to be aligned with the processing direction, thus facilitating the extension of cracks along the processing direction. In order to achieve this laser processing where the polarization direction is aligned with the processing direction, in the configuration of the laser processing apparatus of one aspect of the present invention, the drive direction of the support is either only the rotational direction (single-axis configuration) or only the rotational direction and a second horizontal direction (dual-axis configuration), which is relatively few. Generally, the support is heavy and large; therefore, reducing the number of drive directions (number of drive axes) of the support can suppress the enlargement of the apparatus configuration. Thus, according to one aspect of the present invention, the enlargement of the apparatus configuration can be suppressed, and cracks can easily extend from the modified region along the laser's movement direction.

[0013] In one aspect of the laser processing apparatus of the present invention, the control unit, while focusing a portion of the focusing area on the workpiece at a position separated from the support in the second horizontal direction axially, irradiates the workpiece with a laser beam polarized in the first horizontal direction from the irradiation unit and rotates the support, thereby performing a first process of forming a modified region on the workpiece along a ring line. In this case, the modified region along the ring line can be formed by laser processing with the polarization direction along the processing travel direction.

[0014] In one aspect of the laser processing apparatus of the present invention, a control unit irradiates a workpiece with a laser beam polarized in a first horizontal direction from an irradiation unit, and moves the irradiation unit along the first horizontal direction via a first moving mechanism, thereby performing a second process to form a modified region on the workpiece along a straight line extending in the first horizontal direction. In this case, the modified region along the straight line can be formed by laser processing with the polarization direction aligned with the processing travel direction.

[0015] In one aspect of the laser processing apparatus of the present invention, after the execution of the second process, the control unit may rotate the support unit to rotate the object by a certain angle, and then execute the second process again. In this case, by laser processing with the polarization direction along the processing travel direction, multiple linear modification regions extending in different directions can be formed.

[0016] In one aspect of the laser processing apparatus of the present invention, the second moving mechanism may only move the irradiation unit. In this case, the driving direction of the support unit can be only the rotational direction (single-axis structure), which can further suppress the enlargement of the apparatus structure. In addition, the number of driving directions of the support unit is reduced, which relatively increases the design freedom of the support unit. Furthermore, the support unit can be made lighter, and the rotational speed and rotational accuracy of the support unit can be improved.

[0017] In one aspect of the laser processing apparatus of the present invention, the second moving mechanism may only move the support portion. In this case, the number of driving directions of the irradiation portion is reduced, thereby increasing the design freedom of the irradiation portion. Furthermore, there is no movement of the irradiation portion during laser irradiation, thus reducing the vibration of the laser and the vibration applied to the optical system.

[0018] One aspect of the laser processing apparatus of the present invention further includes a third moving mechanism for moving the irradiation unit along the vertical direction, and a control unit may further control the operation of the third moving mechanism. In this case, by moving the irradiation unit through the third moving mechanism, a portion of the laser focusing area can be moved in the vertical direction.

[0019] The effects of the invention

[0020] According to the present invention, a laser processing apparatus can be provided that can suppress the enlargement of the apparatus structure and make cracks easily extend from the modified region along the direction of laser movement. Attached Figure Description

[0021] Figure 1 This is a perspective view of a laser processing apparatus according to one embodiment.

[0022] Figure 2 yes Figure 1 A front view of a portion of the laser processing apparatus shown.

[0023] Figure 3 yes Figure 1 The image shows a front view of the laser processing head of the laser processing device.

[0024] Figure 4 yes Figure 3 The image shows a side view of the laser processing head.

[0025] Figure 5 yes Figure 3The diagram shows the configuration of the optical system of the laser processing head.

[0026] Figure 6 This is a schematic diagram of the optical system of a modified laser processing head.

[0027] Figure 7 This is a front view of a portion of a modified laser processing apparatus.

[0028] Figure 8 This is a structural diagram showing the main components of the laser processing apparatus according to the first embodiment.

[0029] Figure 9 (a) is a top view of the object that will be laser-processed. Figure 9 (b) is a side view of the object that will be laser-processed.

[0030] Figure 10 This is an explanation Figure 8 A top view of laser processing caused by a laser processing device.

[0031] Figure 11 It means Figure 10 The subsequent top view.

[0032] Figure 12 It means Figure 11 The subsequent top view.

[0033] Figure 13 It means Figure 12 The subsequent top view.

[0034] Figure 14 It means Figure 13 The subsequent top view.

[0035] Figure 15 It means Figure 14 The subsequent top view.

[0036] Figure 16 It means Figure 15 The subsequent top view.

[0037] Figure 17 It means Figure 16 The subsequent top view.

[0038] Figure 18 This is a structural diagram showing the main components of the laser processing apparatus according to the second embodiment.

[0039] Figure 19 This is an explanation Figure 18 A top view of laser processing caused by a laser processing device.

[0040] Figure 20 It means Figure 19 The subsequent top view.

[0041] Figure 21 It means Figure 20 The subsequent top view.

[0042] Figure 22 It means Figure 21 The subsequent top view. Detailed Implementation

[0043] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Identical or equivalent parts will be marked with the same symbols in the drawings, and repeated descriptions will be omitted.

[0044] [Structure of a laser processing device]

[0045] like Figure 1 As shown, the laser processing apparatus 1 includes: multiple moving mechanisms 5 and 6, a support unit 7, a pair of laser processing heads 10A and 10B, a light source unit 8, and a control unit 9. Hereinafter, the first horizontal direction will be referred to as the X direction, the horizontal direction perpendicular to the first horizontal direction, i.e., the second horizontal direction, will be referred to as the Y direction, and the vertical direction will be referred to as the Z direction.

[0046] The moving mechanism 5 includes: a fixed part 51, a moving part 53, and a mounting part 55. The fixed part 51 is mounted on the device frame 1a. The moving part 53 is mounted on a track provided on the fixed part 51 and can move along the Y direction. The mounting part 55 is mounted on a track provided on the moving part 53 and can move along the X direction.

[0047] The moving mechanism 6 includes: a fixed part 61, a pair of moving parts 63 and 64, and a pair of mounting parts 65 and 66. The fixed part 61 is mounted on the device frame 1a. Each of the pair of moving parts 63 and 64 is mounted on a track provided on the fixed part 61 and can move independently along the Y direction. The mounting part 65 is mounted on a track provided on the moving part 63 and can move along the Z direction. The mounting part 66 is mounted on a track provided on the moving part 64 and can move along the Z direction. In other words, for the device frame 1a, each of the pair of mounting parts 65 and 66 can move along the Y direction and the Z direction respectively.

[0048] The support part 7 is mounted on the rotation axis of the mounting part 55 provided in the moving mechanism 5, and can rotate with the axis parallel to the Z direction as its center line. That is, the support part 7 can move along both the X and Y directions and can rotate with the axis parallel to the Z direction as its center line. The support part 7 supports the object 100 along the X and Y directions. The object 100 is, for example, a wafer.

[0049] like Figure 1 and Figure 2As shown, laser processing head 10A is mounted on mounting portion 65 of the moving mechanism 6. Laser processing head 10A is used to irradiate the object 100 supported by the support portion 7 with laser L1 when facing the support portion 7 in the Z direction. Laser processing head 10B is mounted on mounting portion 66 of the moving mechanism 6. Laser processing head 10B is used to irradiate the object 100 supported by the support portion 7 with laser L2 when facing the support portion 7 in the Z direction.

[0050] The light source unit 8 has a pair of light sources 81 and 82. Light source 81 outputs laser L1. Laser L1 is emitted from the emission section 81a of light source 81 and guided to the laser processing head 10A via optical fiber 2. Light source 82 outputs laser L2. Laser L2 is emitted from the emission section 82a of light source 82 and guided to the laser processing head 10B via another optical fiber 2.

[0051] The control unit 9 controls various parts of the laser processing apparatus 1 (multiple moving mechanisms 5 and 6, a pair of laser processing heads 10A and 10B, and the light source unit 8, etc.). The control unit 9 is a computer device comprising a processor, memory, storage unit, and communication elements. In the control unit 9, software (programs) read into the memory are executed by the processor; the reading and writing of data in the memory and storage unit, as well as communication via the communication elements, are controlled by the processor. Thus, the control unit 9 performs various functions.

[0052] An example of processing caused by a laser processing apparatus 1 configured as described above will be described. This example of processing involves cutting a wafer, i.e., the object 100, into multiple chips and forming modified regions inside the object 100 along multiple lines set in a lattice pattern.

[0053] First, the moving mechanism 5 moves the support portion 7 along the X and Y directions, so that the support portion 7 supporting the object 100 is opposite to a pair of laser processing heads 10A and 10B in the Z direction. Next, the moving mechanism 5 rotates the support portion 7 about an axis parallel to the Z direction, so that multiple lines extending in one direction from the object 100 are aligned along the X direction.

[0054] Next, the moving mechanism 6 moves the laser processing head 10A along the Y direction, so that the focusing point of laser L1 is located on a line extending in one direction. Conversely, the moving mechanism 6 moves the laser processing head 10B along the Y direction, so that the focusing point of laser L2 is located on another line extending in one direction. Next, the moving mechanism 6 moves the laser processing head 10A along the Z direction, so that the focusing point of laser L1 is located inside the object 100. Conversely, the moving mechanism 6 moves the laser processing head 10B along the Z direction, so that the focusing point of laser L2 is located inside the object 100.

[0055] Next, light source 81 outputs laser L1, causing laser processing head 10A to irradiate object 100 with laser L1, and light source 82 outputs laser L2, causing laser processing head 10B to irradiate object 100 with laser L2. Simultaneously, moving mechanism 5 moves support 7 along the X direction, causing the focusing point of laser L1 to move relative to each other along a line extending in one direction (laser L1 scans), and causing the focusing point of laser L2 to move relative to each other along other lines extending in one direction (laser L2 scans). In this way, laser processing apparatus 1 forms modified regions inside object 100 along each of the multiple lines extending in one direction along object 100.

[0056] Next, the moving mechanism 5 rotates the support 7 around an axis parallel to the Z direction, causing multiple lines of the object 100 extending in another direction orthogonal to one direction to extend along the X direction.

[0057] Next, the moving mechanism 6 moves the laser processing head 10A along the Y direction, so that the focusing point of laser L1 is located on a line extending in the other direction. Conversely, the moving mechanism 6 moves the laser processing head 10B along the Y direction, so that the focusing point of laser L2 is located on another line extending in the other direction. Next, the moving mechanism 6 moves the laser processing head 10A along the Z direction, so that the focusing point of laser L1 is located inside the object 100. Conversely, the moving mechanism 6 moves the laser processing head 10B along the Z direction, so that the focusing point of laser L2 is located inside the object 100.

[0058] Next, light source 81 outputs laser L1, causing laser processing head 10A to irradiate object 100 with laser L1, and light source 82 outputs laser L2, causing laser processing head 10B to irradiate object 100 with laser L2. Simultaneously, moving mechanism 5 moves support 7 along the X direction, causing the focusing point of laser L1 to move relative to a line extending in another direction (laser L1 scans), and causing the focusing point of laser L2 to move relative to other lines extending in another direction (laser L2 scans). In this way, laser processing apparatus 1 forms modified regions inside object 100 along each of multiple lines extending in a direction orthogonal to one direction.

[0059] Furthermore, in one example of the aforementioned processing, light source 81 outputs a transmissive laser L1 to the object 100 via pulse oscillation, and light source 82 outputs a transmissive laser L2 to the object 100 via pulse oscillation. When this laser is focused inside the object 100, the laser is specifically absorbed at the focal point, forming a modified region inside the object 100. A modified region refers to a region whose density, refractive index, mechanical strength, and other physical properties differ from the surrounding unmodified region. Examples of modified regions include melt-processed regions, cracked regions, insulation failure regions, and regions with refractive index changes.

[0060] When a laser output via pulse oscillation is directed onto an object 100, and the laser's focal point is moved relative to a line set on the object 100, multiple modified particles will form a row along the line. A single modified particle is formed by irradiation with a single laser pulse. A row of modified regions is a collection of multiple modified particles arranged side-by-side. Adjacent modified particles may be connected or separated due to the relative movement speed of the laser's focal point relative to the object 100 and the laser's repetition frequency.

[0061] [Structure of a laser processing head]

[0062] like Figure 3 and Figure 4 As shown, the laser processing head 10A includes: a frame 11, an incident part 12, an adjustment part 13, and a focusing part 14.

[0063] The frame 11 has: a first wall portion 21 and 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 are opposite to each other in the X direction. The third wall portion 23 and the fourth wall portion 24 are opposite to each other in the Y direction. The fifth wall portion 25 and the sixth wall portion 26 are opposite to each other in the Z direction.

[0064] 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. Alternatively, the distance between the first wall portion 21 and the second wall portion 22 may be equal to or greater than the distance between the fifth wall portion 25 and the sixth wall portion 26.

[0065] In the laser processing head 10A, the first wall portion 21 is located on the side of the fixed portion 61 of the moving mechanism 6, the second wall portion 22 is located on the side opposite to the fixed portion 61, the third wall portion 23 is located on the side of the mounting portion 65 of the moving mechanism 6, and the fourth wall portion 24 is located on the side opposite to the mounting portion 65, i.e., the side of the laser processing head 10B (see reference). Figure 2 That is, the fourth wall portion 24 is the opposite wall portion of the frame 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 side of the support portion 7.

[0066] The frame 11 is configured such that, with the third wall portion 23 positioned on the mounting portion 65 side of the moving mechanism 6, the frame 11 is mounted on the mounting portion 65. Specifically, the mounting portion 65 includes a base plate 65a and a mounting plate 65b. The base plate 65a is mounted on a track provided on the moving portion 63 (see reference). Figure 2 Mounting plate 65b is erected on the end of the base plate 65a on the side of the laser processing head 10B (see reference). Figure 2 The frame 11, with its third wall portion 23 in contact with the mounting plate 65b, is screwed onto the mounting plate 65b via bolts 28 through the base 27, thereby mounting it onto the mounting portion 65. The base 27 is provided on the first wall portion 21 and the second wall portion 22. The frame 11 is detachable from the mounting portion 65.

[0067] An incident portion 12 is mounted on the fifth wall portion 25. The incident portion 12 allows laser L1 to enter the frame 11. The incident portion 12 is biased towards the second wall portion 22 in the X direction and towards the fourth wall portion 24 in the Y direction. That is, the distance between the incident portion 12 in the X direction and the second wall portion 22 is smaller than the distance between the incident portion 12 in the X direction and the first wall portion 21, and the distance between the incident portion 12 in the Y direction and the fourth wall portion 24 is smaller than the distance between the incident portion 12 in the X direction and the third wall portion 23.

[0068] The incident section 12 is configured to allow connection to the connection end 2a of the optical fiber 2. At the connection end 2a of the optical fiber 2, a collimating lens is provided to collimate the laser L1 emitted from the exit end of the fiber, but no isolator is provided to suppress reflected light. This isolator is located along the fiber path closer to the light source 81 than at the connection end 2a. This allows for miniaturization of the connection end 2a, and even the incident section 12. Alternatively, an isolator may be provided at the connection end 2a of the optical fiber 2.

[0069] An adjustment unit 13 is disposed within the frame 11. The adjustment unit 13 adjusts the laser L1 incident from the incident part 12. Each component of the adjustment unit 13 is mounted on an optical base 29 provided within the frame 11. The optical base 29 is mounted on the frame 11 in such a way that it divides the area within the frame 11 into an area on the side of the third wall portion 23 and an area on the side of the fourth wall portion 24. The optical base 29 is integral with the frame 11. Each component of the adjustment unit 13 is mounted on the optical base 29 on the fourth wall portion 24 side. Details regarding each component of the adjustment unit 13 will be described later.

[0070] A focusing section 14 is disposed on the sixth wall portion 26. Specifically, the focusing section 14 is disposed on the sixth wall portion 26 with its insertion through the hole 26a formed thereon. The focusing section 14 focuses the laser L1, which has been adjusted by the adjusting section 13, and emits it outside the frame 11. The focusing section 14 is biased towards the second wall portion 22 in the X direction and towards the fourth wall portion 24 in the Y direction. That is, when viewed from the Z direction, the focusing section 14 is disposed towards the fourth wall portion 24 of the frame 11. In other words, the distance between the focusing section 14 and the second wall portion 22 in the X direction is smaller than the distance between the focusing section 14 and the first wall portion 21 in the X direction, and the distance between the focusing section 14 and the fourth wall portion 24 in the Y direction is smaller than the distance between the focusing section 14 and the third wall portion 23 in the X direction.

[0071] like Figure 5 As shown, the adjustment unit 13 includes an attenuator 31, a beam expander 32, and a reflector 33. The incident portion 12, and the attenuator 31, beam expander 32, and reflector 33 of the adjustment unit 13 are arranged on a straight line A1 extending along the Z direction. The attenuator 31 and beam expander 32 are arranged on the straight line A1 between the incident portion 12 and the reflector 33. The attenuator 31 adjusts the output of the laser L1 incident from the incident portion 12. The beam expander 32 enlarges the diameter of the laser L1 output after adjustment by the attenuator 31. The reflector 33 reflects the laser L1 whose diameter has been enlarged by the beam expander 32.

[0072] The adjustment unit 13 further includes a reflective spatial light modulator 34 and an imaging optical system 35. The reflective spatial light modulator 34, the imaging optical system 35, and the focusing unit 14 of the adjustment unit 13 are arranged on a straight line A2 extending along the Z direction. The reflective spatial light modulator 34 modulates the laser L1 reflected by the mirror 33. The reflective spatial light modulator 34 is, for example, a spatial light modulator (SLM) of a reflective liquid crystal on silicon (LCOS). The imaging optical system 35 is a two-sided telecentric optical system that forms an imaging relationship between the reflecting surface 34a of the reflective spatial light modulator 34 and the entrance pupil surface 14a of the focusing unit 14. The imaging optical system 35 is composed of three or more lenses.

[0073] Lines A1 and A2 are located on a plane perpendicular to the Y direction. Line A1 is located on the side of the second wall portion 22 relative to line A2. In the laser processing head 10A, laser L1 enters the frame 11 from the incident portion 12 and travels along line A1. After being reflected sequentially by the reflector 33 and the reflective spatial light modulator 34, it travels along line A2 and exits from the focusing portion 14 to the outside of the frame 11. Furthermore, the arrangement order of the attenuator 31 and the beam expander 32 can be reversed. Additionally, the attenuator 31 can be positioned between the reflector 33 and the reflective spatial light modulator 34. Furthermore, the adjustment portion 13 can also have other optical components (such as a steering mirror positioned before the beam expander 32).

[0074] The laser processing head 10A also includes: a dichroic mirror 15, a measuring unit 16, an observation unit 17, a driving unit 18, and a circuit unit 19.

[0075] The dichroic mirror 15 is positioned on line A2 between the imaging optical system 35 and the focusing section 14. That is, the dichroic mirror 15 is positioned within the frame 11 between the adjustment section 13 and the focusing section 14. The dichroic mirror 15 is mounted on the optical base 29 on the fourth wall side 24. The dichroic mirror 15 allows laser L1 to be transmitted. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 can be, for example, a cuboid shape, or configured as two plates with a twisted relationship.

[0076] The measuring unit 16 is disposed on the first wall portion 21 side of the frame 11, relative to the adjustment portion 13. The measuring unit 16 is mounted on the optical base 29 on the fourth wall portion 24 side. The measuring unit 16 outputs measuring light L10 for measuring the distance between the surface of the object 100 (e.g., the surface on the side where laser L1 is incident) and the focusing unit 14, and detects the measuring light L10 reflected from the surface of the object 100 via the focusing unit 14. In other words, the measuring light L10 output from the measuring unit 16 is irradiated onto the surface of the object 100 via the focusing unit 14, and the measuring light L10 reflected from the surface of the object 100 is detected by the measuring unit 16 via the focusing unit 14.

[0077] 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 mounted on the optical base 29 on the fourth wall 24 side, and then exits from the focusing unit 14 to the outside of the frame 11. The measurement light L10 reflected on the surface of the object 100 enters the frame 11 from the focusing unit 14, is sequentially reflected by the dichroic mirror 15 and the beam splitter 20, and then enters the measurement unit 16, where it is detected by the measurement unit 16.

[0078] The observation unit 17 is located within the frame 11 and is disposed on the side of the first wall portion 21 relative to the adjustment portion 13. The observation unit 17 is mounted on the optical base 29 on the side of the fourth wall portion 24. The observation unit 17 outputs observation light L20 for observing the surface of the object 100 (e.g., the surface on the side where laser L1 is incident), and detects the observation light L20 reflected from the surface of the object 100 via the focusing unit 14. In other words, the observation light L20 output from the observation unit 17 is irradiated onto the surface of the object 100 via the focusing unit 14, and the observation light L20 reflected from the surface of the object 100 is detected by the observation unit 17 via the focusing unit 14.

[0079] 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 then exits from the condenser 14 to the outside of the frame 11. The observation light L20 reflected on the surface of the object 100 enters the frame 11 from the condenser 14, is reflected by the dichroic mirror 15, passes through the beam splitter 20, and enters the observation unit 17, where it is detected. Furthermore, the wavelengths of the laser L1, the measuring light L10, and the observation light L20 are different from each other (at least their center wavelengths are offset from each other).

[0080] The drive unit 18 is mounted on the optical base 29 on the side of the fourth wall 24. The drive unit 18, for example, moves the focusing part 14 disposed on the sixth wall 26 along the Z direction by the driving force of the piezoelectric element.

[0081] The circuit section 19 is disposed on the third wall 23 side of the optical base 29 within the frame 11. That is, the circuit section 19 is disposed on the third wall 23 side of the frame 11, opposite to the adjustment section 13, the measuring section 16, and the observation section 17. The circuit section 19 is, for example, a multi-chip circuit board. The circuit section 19 processes the signal output from the measuring section 16 and the signal input to the reflective spatial light modulator 34. The circuit section 19 controls the drive section 18 based on the signal output from the measuring section 16. As an example, the circuit section 19 controls the drive section 18 based on the signal output from the measuring section 16 to maintain a constant distance between the surface of the object 100 and the focusing section 14 (i.e., to maintain a constant distance between the surface of the object 100 and the focusing point of the laser L1). Furthermore, a connector (not shown) is provided in the frame 11, which connects to the control section 9 (see reference 1). Figure 1 Wiring for , etc.

[0082] The laser processing head 10B, like the laser processing head 10A, includes: a frame 11, an incident section 12, an adjustment section 13, a focusing section 14, a dichroic mirror 15, a measuring section 16, an observation section 17, a driving section 18, and a circuit section 19. However, the components of the laser processing head 10B, such as... Figure 2 As shown, the virtual plane passing through the midpoint between the pair of mounting parts 65 and 66 and perpendicular to the Y direction is configured to have a face-symmetric relationship with each component of the laser processing head 10A.

[0083] For example, the frame 11 of the laser processing head 10A is mounted on the mounting portion 65, with the fourth wall portion 24 located on the laser processing head 10B side relative to the third wall portion 23, and the sixth wall portion 26 located on the support portion 7 side relative to the fifth wall portion 25. Conversely, the frame 11 of the laser processing head 10B is mounted on the mounting portion 66, with the fourth wall portion 24 located on the laser processing head 10A side relative to the third wall portion 23, and the sixth wall portion 26 located on the support portion 7 side relative to the fifth wall portion 25. That is, in the laser processing head 10B as well, the fourth wall portion 24 is a relative wall portion of the frame of the laser processing head 10A along the Y direction. In addition, in the laser processing head 10B as well, the focusing portion 14, when viewed from the Z direction, is positioned biased towards the fourth wall portion (relative wall portion) 24 of the frame 11.

[0084] The frame 11 of the laser processing head 10B is mounted on the mounting portion 66 with the third wall portion 23 positioned on the mounting portion 66 side. Specifically, the mounting portion 66 includes a base plate 66a and a mounting plate 66b. The base plate 66a is mounted on a track provided on the moving portion 63. The mounting plate 66b is located at the end of the base plate 66a that is vertically positioned on the side of the laser processing head 10A. The frame 11 of the laser processing head 10B is mounted on the mounting portion 66 with the third wall portion 23 in contact with the mounting plate 66b. The frame 11 of the laser processing head 10B is detachable from the mounting portion 66.

[0085] [The function and effects of laser processing heads]

[0086] In the laser processing head 10A, since the light source for outputting the laser L1 is not located within the frame 11, miniaturization of the frame 11 is possible. Furthermore, within the frame 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 focusing portion 14 disposed on the sixth wall portion 26 is biased towards the fourth wall portion 24 in the Y direction. Therefore, when the frame 11 is moved along a direction perpendicular to the optical axis of the focusing portion 14, for example, even if other components (such as the laser processing head 10B) are present on the fourth wall portion 24 side, the focusing portion 14 can be moved closer to those other components. Therefore, in the laser processing head 10A, the focusing portion 14 can also be moved along a direction perpendicular to its optical axis.

[0087] Furthermore, in the laser processing head 10A, the incident portion 12 is located on the fifth wall portion 25, offset from the fourth wall portion 24 in the Y direction. This allows other components (such as the circuit portion 19) to be arranged in the area within the frame 11 where the adjustment portion 13 is located on the third wall portion 23 side, effectively utilizing that area.

[0088] Furthermore, in the laser processing head 10A, the focusing part 14 is biased towards the second wall part 22 in the X direction. Therefore, when the frame 11 is moved in a direction perpendicular to the optical axis of the focusing part 14, for example, even if there are other components on the second wall part 22 side, the focusing part 14 can be brought closer to those other components.

[0089] Furthermore, in the laser processing head 10A, the incident portion 12 is located on the fifth wall portion 25, biased towards the fourth wall portion 24 in the Y direction and biased towards the second wall portion 22 in the X direction. Therefore, other components (such as the circuit portion 19) can be arranged in the region within the frame 11 relative to the adjustment portion 13 on the third wall portion 23 side, effectively utilizing this region. Furthermore, other components (such as the measuring portion 16 and the observing portion 17) can be arranged in the region within the frame 11 relative to the adjustment portion 13 on the first wall portion 21 side, effectively utilizing this region.

[0090] Furthermore, in the laser processing head 10A, the measuring section 16 and the observing section 17 are located in the region within the frame 11, positioned relative to the adjusting section 13 on the side of the first wall 21. The circuit section 19 is located in the region within the frame 11, positioned relative to the adjusting section 13 on the side of the third wall 23. The dichroic mirror 15 is located within the frame 11, positioned between the adjusting section 13 and the focusing section 14. This allows for efficient utilization of the region within the frame 11. Additionally, in the laser processing apparatus 1, processing can be performed based on the measured distance between the surface of the object 100 and the focusing section 14. Furthermore, in the laser processing apparatus 1, processing can also be performed based on the observed surface of the object 100.

[0091] Furthermore, in the laser processing head 10A, the circuit section 19 controls the drive section 18 based on the signal output by the measurement section 16. Therefore, the position of the focusing point of the laser L1 can be adjusted based on the measurement result of the distance between the surface of the object 100 and the focusing section 14.

[0092] Furthermore, in the laser processing head 10A, the attenuator 31, beam expander 32, and reflector 33 of the incident section 12 and the adjustment section 13 are arranged on a straight line A1 extending along the Z direction. The reflective spatial light modulator 34, imaging optical system 35, and focusing section 14 of the adjustment section 13 are arranged on a straight line A2 extending along the Z direction. Thus, the adjustment section 13, which includes the attenuator 31, beam expander 32, reflective spatial light modulator 34, and imaging optical system 35, can be compactly configured.

[0093] Furthermore, in the laser processing head 10A, line A1 is located on the side of the second wall portion 22 relative to line A2. Thus, when other optical systems (such as measuring units 16 and observing units 17) using the focusing unit 14 are configured in the region of the frame 11 relative to the adjustment unit 13 on the side of the first wall portion 21, the degree of freedom in configuring these other optical systems can be increased.

[0094] The same functions and effects can be achieved through the laser processing head 10B.

[0095] [Example of a modified laser processing head]

[0096] like Figure 6 As shown, the incident section 12, the adjustment section 13, and the focusing section 14 can also be arranged on a straight line A extending along the Z direction. Thus, the adjustment section 13 can be compactly configured. In this case, the adjustment section 13 can be configured without or without the reflective spatial light modulator 34 and the imaging optical system 35. Alternatively, the adjustment section 13 can also include an attenuator 31 and a beam expander 32. Thus, the adjustment section 13 with the attenuator 31 and the beam expander 32 can be compactly configured. Furthermore, the arrangement order of the attenuator 31 and the beam expander 32 can be reversed.

[0097] Alternatively, at least one of guiding the laser L1 from the emission portion 81a of the light source unit 8 to the incident portion 12 of the laser processing head 10A, and guiding the laser L2 from the emission portion 82a of the light source unit 8 to the incident portion 12 of the laser processing head 10B, may be implemented using a reflector. Figure 7 This is a front view of a part of the laser processing apparatus 1 in which laser L1 is guided by a reflector. Figure 7 The structure shown has a reflector 3 for reflecting laser L1, which is mounted on the moving part 63 of the moving mechanism 6. It is opposite to the emission part 81a of the light source unit 8 in the Y direction and opposite to the incident part 12 of the laser processing head 10A in the Z direction.

[0098] exist Figure 7 The configuration shown maintains the mirror 3 facing the emission portion 81a of the light source unit 8 even when the moving part 63 of the moving mechanism 6 moves along the Y direction. Similarly, even when the mounting part 65 of the moving mechanism 6 moves along the Z direction, the mirror 3 remains facing the incident portion 12 of the laser processing head 10A. Therefore, regardless of the position of the laser processing head 10A, the laser L1 emitted from the emission portion 81a of the light source unit 8 can be reliably incident on the incident portion 12 of the laser processing head 10A. Furthermore, a light source such as a high-power long / short pulse laser, which is difficult to guide by the optical fiber 2, can be used.

[0099] In addition, Figure 7 With the configuration shown, the reflector 3 is mounted on the moving part 63 of the moving mechanism 6, making at least one angle adjustment and position adjustment possible. Thus, the laser L1 emitted from the emission part 81a of the light source unit 8 can be more reliably incident on the incident part 12 of the laser processing head 10A.

[0100] Alternatively, the light source unit 8 may have only one light source. In this case, the light source unit 8 may also be configured to emit a portion of the laser light output from a light source from the emission section 81a and the remaining portion of the laser light from the emission section 82a.

[0101] <First Implementation>

[0102] Next, the first embodiment will be described. Hereinafter, descriptions that are repeated in the above embodiment will be omitted.

[0103] like Figure 8As shown, the laser processing apparatus 101 of the first embodiment is an apparatus that irradiates a portion of a focusing area (hereinafter also referred to as a "focusing point") onto a workpiece 100 with laser L1, thereby forming a modified region on the workpiece 100. The laser processing apparatus 101 is an apparatus that performs laser processing, including trimming and radial cutting, on the workpiece 100 to obtain (manufacture) semiconductor devices.

[0104] Trimming is a process that removes unwanted parts from the object 100. Radial cutting is a process used to separate the unwanted parts removed by trimming. Both trimming and radial cutting include laser processing methods that irradiate the object 100 with a laser L1 by focusing a beam onto the object 100, thereby forming a modified region on the object 100.

[0105] Object 100 may include, for example, a semiconductor wafer formed in a circular plate shape. Object 100 is not particularly limited and may be formed of various materials and have various shapes. Functional elements (not shown) are formed on the surface 100a of object 100. Functional elements may include, for example, light-receiving elements such as photodiodes, light-emitting elements such as laser diodes, and circuit elements such as memory.

[0106] like Figure 9 (a) and Figure 9 As shown in (b), an effective region R and a removal region E are defined on the object 100. The effective region R corresponds to the portion of the acquired semiconductor element. Here, the effective region R is a circular plate-shaped portion including the central portion when the object 100 is viewed from the thickness direction. The removal region E is a region of the object 100 that extends beyond the effective region R. The removal region E is the outer edge portion of the object 100 outside the effective region R. Here, the removal region E is an annular portion surrounding the effective region R. The removal region E includes the peripheral portion (the chamfered outer edge) when the object 100 is viewed from the thickness direction. The setting of the effective region R and the removal region E can be performed in the control unit 9. The effective region R and the removal region E can also be specified by coordinates.

[0107] On the object 100, a line M3 is provided as a trimming predetermined line. Line M3 is a line that is predetermined to form the modified region 4. Line M3 is a loop-shaped line extending into a ring shape on the inner side of the outer edge of the object 100. Here, line M3 extends into a ring shape. Line M3 is set at the boundary between the effective region R and the removal region E of the object 100. In addition, on the object 100, a line M4 is provided as a radial cutting predetermined line. Line M4 is a line that is predetermined to form the modified region by radial cutting. When viewed from the laser incident surface, line M4 is a straight line extending radially along the radial direction of the object 100. For example, when viewed from the laser incident surface, line M4 is set to divide the removal region E into multiple equal parts (in this case, four parts) in the circumferential direction. Although lines M3 and M4 are virtual lines, they can also be actually drawn lines. The setting of lines M3 and M4 can be performed in the control unit 9. Lines M3 and M4 can also be specified as coordinates.

[0108] The object 100 may also have a aligning object (not shown). The aligning object, for example, has a certain relationship with the position of the object 100 in the 0° direction in the θ direction (the rotation direction of the support 7 about axis C). The position in the 0° direction refers to the position of the object 100 that serves as a reference in the θ direction. Examples of aligning objects include notches formed on the outer edge, directional planes, or patterns of functional elements.

[0109] like Figure 8 As shown, the laser processing apparatus 101 includes: a support unit 7, a laser processing head (irradiation unit) 10A, an X-direction moving mechanism (first moving mechanism) 110, a Y-direction moving mechanism (second moving mechanism) 120, a Z-direction moving mechanism (third moving mechanism) 130, and a control unit 9.

[0110] Support 7 supports object 100. Object 100 is placed on support 7, for example, with the back surface 100b of object 100 as the laser incident surface side (i.e., the upper side) and the surface 100a as the platform 107 side (i.e., the lower side). Support 7 has an axis C (see reference) located at its center and along the Z direction. Figure 9 The support 7 can rotate in the θ direction around axis C. The support 7 is driven to rotate by the driving force of a known drive device such as an engine.

[0111] The laser processing head 10A irradiates an object 100 supported by the support section 7 with a laser L1 polarized in the X direction in the Z direction, thereby forming a modified region inside the object 100. The polarization direction of the laser L1 (hereinafter referred to simply as "polarization direction") can be controlled by the reflective spatial light modulator 34 provided in the laser processing head 10A. Specifically, a modulation pattern containing a predetermined slit pattern is displayed in the liquid crystal layer of the reflective spatial light modulator 34, thereby enabling the reflective spatial light modulator 34 to function as a polarizer and adjust the polarization direction of the laser L1 to the X direction. The modulation pattern refers to the holographic pattern imparted by modulation. The predetermined slit pattern is preset and stored in the control section 9. Furthermore, the polarization direction of the laser L1 is not limited to being controlled by the reflective spatial light modulator 34; it can also be controlled using various known techniques. For example, a λ / 2 wavelength plate can be used to adjust the polarization direction of the laser L1 to the X direction. The laser processing head 10A constitutes an irradiation section.

[0112] like Figure 8 and Figure 10 As shown, the Z-direction moving mechanism 130 is a mechanism that moves the laser processing head 10A along the Z-direction. The Z-direction moving mechanism 130 has a Z-axis track 130A. The Z-axis track 130A is a track extending along the Z-direction. The laser processing head 10A is mounted on the Z-axis track 130A via the mounting part 65. This Z-direction moving mechanism 130 moves the laser processing head 10A along the Z-axis track 130A in the Z-direction by the driving force of a known drive device such as an engine, thereby moving the focusing point of the laser L1 along the Z-direction. The Z-direction moving mechanism 130 corresponds to the moving mechanism 6 described above (see reference 6). Figure 1 Part of ).

[0113] The X-direction moving mechanism 110 is a mechanism that moves the laser processing head 10A along the polarization direction, i.e., the X-direction. The X-direction moving mechanism 110 has an X-axis track 110A, which extends along the X-direction. The laser processing head 10A is mounted on the X-axis track 110A via the Z-axis track 130A and the mounting part 65. This X-direction moving mechanism 110 uses the driving force of a known drive device such as an engine to move the laser processing head 10A along the X-axis track 110A in the X-direction, thereby moving the focusing point of the laser L1 along the X-direction.

[0114] The Y-direction moving mechanism 120 is a mechanism for moving the laser processing head 10A along the Y-direction. The Y-direction moving mechanism 120 has a Y-axis track 120A, which extends along the Y-direction. The laser processing head 10A is mounted on the Y-axis track 120A via the X-axis track 110A, the Z-axis track 130A, and the mounting part 65. This Y-direction moving mechanism 120 uses the driving force of a known drive device such as an engine to move the laser processing head 10A along the Y-axis track 120A in the Y-direction, thereby moving the focusing point of the laser L1 along the Y-direction. The Y-direction moving mechanism 120 corresponds to the moving mechanism 6 described above (see reference 6). Figure 1 Part of ).

[0115] The control unit 9 is a computer device configured to include a processor, memory, storage unit, and communication elements. In the control unit 9, software (programs) read into the memory are executed by the processor; the reading and writing of data in the memory and storage unit, as well as communication via the communication elements, are controlled by the processor. Thus, the control unit 9 performs various functions.

[0116] Control unit 9 controls the operation of support unit 7, laser processing head 10A, X-direction moving mechanism 110, Y-direction moving mechanism 120, and Z-direction moving mechanism 130. Control unit 9 also controls the rotation of support unit 7, the irradiation of laser L1 from laser processing head 10A, and the movement of the focusing point of laser L1. Control unit 9 can perform various controls based on rotation information (hereinafter referred to as "θ information") related to the amount of rotation of support unit 7. θ information can be obtained from the driving amount of the drive device that rotates support unit 7, or from other sensors. θ information can be obtained using various known methods. Here, θ information includes the rotation angle based on the state of object 100 when it is located in the 0° direction.

[0117] The control unit 9, while rotating the support unit 7 and positioning the focusing point along line M3 on the object 100, controls the start and stop of laser L1 irradiation from the laser processing head 10A based on θ information, thereby performing a trimming process (first process) to form a modified region along the periphery of the effective area R. In the trimming process, with the focusing point on line M3 separating the support unit 7 from the axis C in the Y direction on the object 100, the laser processing head 10A irradiates the object 100 with laser L1 polarized in the X direction and rotates the support unit 7, thereby forming a modified region on the object 100 along line M3. The control unit 9 repeatedly performs the trimming process by changing the position of the focusing point in the Z direction, forming multiple rows of modified regions along line M3 in the Z direction.

[0118] The formation and cessation of the modified region caused by the control unit 9 can be achieved as follows. For example, in the laser processing head 10A, the start and stop (ON / OFF) of the irradiation (output) of the laser L1 are switched, thereby switching the formation and cessation of the modified region. Specifically, when the laser oscillator is composed of a solid-state laser, the ON / OFF of the Q-switch (AOM (acoustic optical modulator), EOM (electro-optical modulator), etc.) provided in the resonant cavity is switched, thereby switching the start and stop of the irradiation of the laser L1 at high speed. When the laser oscillator is composed of a fiber laser, the ON / OFF of the output of the semiconductor laser constituting the seed laser and the amplifier (excitation) laser is switched, thereby switching the start and stop of the irradiation of the laser L1 at high speed. When the laser oscillator uses an external modulation element, the ON / OFF of the external modulation element (AOM, EOM, etc.) provided outside the resonant cavity is switched, thereby switching the ON / OFF of the irradiation of the laser L1 at high speed.

[0119] Alternatively, the switching of the formation and cessation of the modified region caused by the control unit 9 can be implemented as follows: For example, the formation and cessation of the modified region can be switched by controlling a mechanical mechanism such as a shutter to close the optical path of laser L1. The formation of the modified region can also be stopped by switching laser L1 to CW light (continuous wave). The formation of the modified region can also be stopped by displaying the focusing state of laser L1 as a pattern of a state where modification is not possible (e.g., a pattern of a rough pattern of laser scattering) in the liquid crystal layer of the reflective spatial light modulator 34. The formation of the modified region can also be stopped by controlling the output adjustment unit such as an attenuator to reduce the output of laser L1 in a way that the modified region cannot be formed. The formation of the modified region 4 can also be stopped by switching the polarization direction. The formation of the modified region can also be stopped by scattering (dispersing) laser L1 in a direction other than the optical axis.

[0120] The control unit 9, without rotating the platform 107, irradiates the removal area E with laser L1 and moves the focusing point of the laser L1 in the X direction, thereby performing a radial cutting process (second process) to form a modified region in the removal area E along the X direction. The radial cutting process involves appropriately controlling the irradiation of the laser L1 from the laser processing head 10A, which is polarized in the X direction, while moving the laser processing head 10A appropriately along the X direction via the X-direction moving mechanism 110, thereby forming a modified region in the removal area E along the line M4 extending in the X direction. After the radial cutting process is executed, 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 performs the radial cutting process again. This certain angle is, for example, 90°. The certain angle is not particularly limited. The rotation of the object 100 in the θ direction and the repeated radial cutting process can be performed multiple times, for example, corresponding to a certain angle.

[0121] The control unit 9 controls at least one of the following: the rotation of the support unit 7, the irradiation of the laser L1 from the laser processing head 10A, and the movement of the focusing point of the laser L1, by setting the spacing between the plurality of modified points enclosed in the modified region. The spacing between the modified points is the interval between adjacent modified points in the direction of movement of the focusing point of the laser L1 (hereinafter also referred to as the "processing travel direction").

[0122] The laser processing apparatus 101 includes a pair of alignment cameras AC with different magnifications. The alignment cameras AC are mounted on the mounting section 65 together with the laser processing head 10A. The alignment cameras AC, for example, use light transmitted through the object 100 to photograph component patterns, etc. The resulting image is an alignment of the position of the laser L1 irradiation on the object 100.

[0123] Next, an example of a method for performing finishing and radial cutting on an object 100 using a laser processing apparatus 101 will be described below.

[0124] First, the object 100 is placed on the support 7 with the back side 100b facing the laser incident surface. A support substrate and adhesive tape are adhered to the surface 100a of the object 100 where the functional components are mounted to protect it.

[0125] Next, the control unit 9 performs a finishing process. During the finishing process, the support unit 7 is rotated so that the object 100 is positioned at 0°. Figure 10 As shown, with the focus point of laser L1 located at the trimming start position, the laser processing head 10A is moved by the X-direction moving mechanism 110 and the Y-direction moving mechanism 120. The trimming start position is, for example, a position on line M3 of the object 100 that is separated from axis C in the Y direction. Next, the rotation of platform 107 begins.

[0126] At the point when the rotational speed of the support 7 reaches a constant speed, the laser L1 irradiation caused by the laser processing head 10A begins. At this time, the polarization direction of the laser L1 is adjusted along the X direction by the reflective spatial light modulator 34. That is, as... Figure 11 As shown, while the support 7 is rotated, a laser L1 polarized in the tangential direction of the rotation, i.e., the X direction, is irradiated. Consequently, the focusing point moves relative to the object 100 along line M3 with the processing travel direction as the X direction, forming a modified region 4 along line M3. This formation of the modified region 4 along line M3 is repeatedly performed by changing the Z-direction position of the trimming start position using the Z-direction moving mechanism 130. Thus, multiple rows of modified regions 4 are formed along line M3 in the Z direction.

[0127] Next, the control unit 9 executes the radial cutting process, performing radial cutting machining. Radial cutting machining, such as... Figure 12 As shown, the laser processing head 10A is moved by the Y-direction moving mechanism 120 in such a way that the Y-direction position between the line M4 extending in the X-direction and the focal point of the laser L1 is the same. In other words, the laser processing head 10A is moved by the Y-direction moving mechanism 120 in such a way that the focal point of the laser L1 is on the extended line (in this case, the focal point of the laser L1 is located on axis C).

[0128] like Figure 13 As shown, the laser processing head 10A is moved to one side (upper side in the figure) in the X direction by the X-direction moving mechanism 110 without rotating the support 7, so that the focusing point of the laser L1 moves linearly along line M4. At the same time, the laser L1 is irradiated from the laser processing head 10A onto the removal area E of the object 100. At this time, the polarization direction of the laser L1 is adjusted to be along the X direction by the reflective spatial light modulator 34. That is, while moving the focusing point relative to the object along line M4 with the processing travel direction in the X direction, the laser L1 with the X direction as the polarization direction is irradiated onto the removal area E. As a result, a modified region 4 is formed in the removal area E along line M4 on one side of the X direction.

[0129] like Figure 14 As shown, the laser processing head 10A is moved to the opposite side in the X direction (shown as the lower side) by the X-direction moving mechanism 110 without rotating the support 7, causing the focusing point of the laser L1 to move linearly along line M4. Simultaneously, the laser L1 is irradiated from the laser processing head 10A onto the removal area E of the object 100. At this time, the polarization direction of the laser L1 is adjusted to be along the X direction by the reflective spatial light modulator 34. That is, while moving the focusing point relative to each other along line M4 with the processing travel direction in the X direction, the laser L1 with the X direction as its polarization direction is irradiated onto the removal area E. Thus, a modified region 4 is formed in the removal area E along line M4 on the opposite side of the X direction. This formation of a pair of modified regions 4 along the same straight line M4 is repeatedly performed by changing the Z-direction position of the focusing point by the Z-direction moving mechanism 130. Thus, multiple rows of modified regions 4 are formed in the Z direction along this pair of lines M4.

[0130] Next, as Figure 15 As shown, after rotating the support 7 by 90°, the above-described radial cutting process is performed again. The repeated radial cutting process is as follows: Figure 16As shown, the laser processing head 10A is moved to one side (upper side in the figure) in the X direction by the X-direction moving mechanism 110 without rotating the support 7, thereby moving the focusing point of the laser L1 along line M4. Simultaneously, the laser L1 is irradiated from the laser processing head 10A onto the removal area E of the object 100. At this time, the polarization direction of the laser L1 is adjusted to be along the X direction by the reflective spatial light modulator 34. That is, while moving the focusing point relative to the line M4 with the processing travel direction in the X direction, the laser L1 with the X direction as its polarization direction is irradiated onto the removal area E. Thus, a modified region 4 is formed in the removal area E along line M4 on one side of the X direction.

[0131] like Figure 17 As shown, the laser processing head 10A is moved to the opposite side of the X direction (shown as the lower side) by the X-direction moving mechanism 110 without rotating the support 7, thus moving the focusing point of the laser L1 along line M4. Simultaneously, the laser L1 is irradiated from the laser processing head 10A onto the removal area E of the object 100. At this time, the polarization direction of the laser L1 is adjusted to be along the X direction by the reflective spatial light modulator 34. That is, while moving the focusing point relative to each other along line M4 with the processing travel direction in the X direction, the laser L1 with the X direction as its polarization direction is irradiated onto the removal area E. Thus, a modified region 4 is formed in the removal area E along line M4 on the opposite side of the X direction. This formation of a pair of modified regions 4 along the same straight line M4 is repeatedly performed by changing the Z-direction position of the focusing point by the Z-direction moving mechanism 130. Thus, multiple rows of modified regions 4 are formed along this pair of lines M4 in the Z direction.

[0132] Then, for example, using a jig or air, the removal region E is cut and removed, with the modified region 4 as the boundary. As a result, a semiconductor device (wafer) is obtained by removing the removal region E of the object 100.

[0133] The laser processing apparatus 101, as described above, allows for a trimming process where the support 7 is rotated while the tangential direction of that rotation becomes the polarization direction. Additionally, it allows for radial cutting where the focusing point is moved linearly along the polarization direction. In other words, both trimming and radial cutting processes can be performed, with the polarization direction aligned with the processing direction. During both trimming and radial cutting, cracks can extend from the modified region 4 along the processing direction, and the amount of extension of the cracks from the modified region 4 along the processing direction can be increased. This reduces the number of scans of the laser L1, allowing for efficient laser processing.

[0134] Furthermore, to achieve this laser processing where the polarization direction is along the processing travel direction, the support 7 in the laser processing apparatus 101 has only one driving direction (θ direction, single-axis structure), which is relatively few. Generally, the support 7 is heavy and large; therefore, reducing the number of driving directions (driving axes) of the support 7 allows for the relatively lightweight laser processing head 10A to become movable, thereby suppressing the need for a large-scale apparatus structure. Thus, according to the laser processing apparatus 101, the need for a large-scale apparatus structure can be suppressed, and cracks can easily extend from the modified region 4 along the processing travel direction. This also helps to prevent an increase in apparatus cost and area.

[0135] In the laser processing apparatus 101, the trimming process performed by the control unit 9 involves focusing the laser beam on the workpiece 100 at a position separated from the axis C in the Y direction. A laser beam L1 with a polarization direction in the X direction is irradiated onto the workpiece 100 from the laser processing head 10A, and the support unit 7 is rotated, thereby forming a modified region 4 on the workpiece 100 along a ring-shaped line M3. In this case, the modified region 4 along the ring-shaped line M3 can be formed by trimming the polarization direction along the processing travel direction.

[0136] In the laser processing apparatus 101, the radial cutting process performed by the control unit 9 involves irradiating the workpiece 100 with a laser L1 polarized in the X direction from the laser processing head 10A, while the laser processing head 10A is moved along the X direction by the X-direction moving mechanism 110, thereby forming a modified region 4 on the workpiece 100 along a line M4 extending in the X direction. In this case, the modified region 4 along the linear line M4 can be formed by radial cutting with the polarization direction aligned with the processing travel direction.

[0137] In the laser processing apparatus 101, after the execution of the radial cutting process, the control unit 9 rotates the support unit 7 to rotate the object 100 by 90° in the θ direction, and then performs the radial cutting process again. In this case, by performing radial cutting with the polarization direction along the processing travel direction, a modified region 4 with multiple lines M4 extending in different directions (here, a pair of lines M4 extending in one direction and a pair of lines M4 extending in other directions orthogonal to one direction) can be formed.

[0138] In the laser processing apparatus 101, the Y-direction moving mechanism 120 moves only the laser processing head 10A. In this case, the driving direction of the support 7 can be only the θ direction (single-axis structure), which can further suppress the enlargement of the apparatus structure. In addition, the number of driving axes of the support 7 is reduced, which relatively increases the design freedom of the support 7. Furthermore, the support 7 can be made lighter, which can improve the rotational speed and rotational accuracy of the support 7.

[0139] The laser processing apparatus 101 also includes a Z-direction moving mechanism 130 and a control unit 9, which further controls the operation of the Z-direction moving mechanism 130. In this case, the laser processing head 10A is moved by the Z-direction moving mechanism 130, thereby allowing the focusing point of the laser L1 to move in the Z direction.

[0140] <Second Implementation Method>

[0141] Next, the second embodiment will be described. Descriptions that are repeated in the first embodiment will be omitted hereafter.

[0142] like Figure 18 and Figure 19 As shown, in the second embodiment of the laser processing apparatus 201, the Y-direction moving mechanism 120 is replaced. Figure 8 This differs from the first embodiment in that it includes a Y-direction moving mechanism 220. The Y-direction moving mechanism 220 is a mechanism that moves the support 7 along the Y-direction. The Y-direction moving mechanism 120 has a Y-axis track 220A. The Y-axis track 220A is a track extending along the Y-direction. The Y-axis track 220A is mounted on the support 7. This Y-direction moving mechanism 220 uses the driving force of a known drive device such as an engine to move the support 7 along the Y-axis track 120A in the Y-direction, thereby moving the focusing point of the laser L1 along the Y-direction. The Y-direction moving mechanism 220 corresponds to the moving mechanism 5 described above (see reference 5). Figure 1 Part of ).

[0143] Next, an example of a method for performing finishing and radial cutting on object 100 using laser processing apparatus 201 will be described below.

[0144] During the finishing and processing, such as Figure 19 As shown, with the focal point of laser L1 at the starting position of the finishing process, the laser processing head 10A is moved by the X-direction moving mechanism 110, and the support 7 is moved by the Y-direction moving mechanism 220. While the support 7 is rotated, laser L1, with its polarization direction being the tangential direction of the rotation, i.e., the X-direction, is irradiated. Thus, the focal point is moved relative to the object along line M3 with the processing travel direction being the X-direction, and a modified region 4 is formed on the object 100 along line M3.

[0145] In radial cutting processes, such as Figure 20 As shown, the support 7 is moved by the Y-direction moving mechanism 220 in the same manner as the Y-direction position between the line M4 extending in the X-direction and the focusing point of the laser L1 (i.e., on the extension line of M4 on the focusing point line of the laser L1). Figure 21As shown, the laser processing head 10A is moved along the X direction by the X-direction moving mechanism 110 without rotating the support 7, causing the focusing point of the laser L1 to move linearly along line M4. Simultaneously, the laser L1 is irradiated from the laser processing head 10A onto the removal area E of the object 100. At this time, the polarization direction of the laser L1 is adjusted to be along the X direction by the reflective spatial light modulator 34. That is, while moving the focusing point relative to each other along line M4 with the processing travel direction in the X direction, the laser L1 with the X direction as its polarization direction is irradiated onto the removal area E. Thus, a modified region 4 is formed in the removal area E along a pair of lines M4 on the same straight line.

[0146] Next, after rotating the support 7 by 90°, the above-described radial cutting process is performed again. The second radial cutting process is as follows: Figure 22 As shown, the laser processing head 10A is moved in the X direction by the X-direction moving mechanism 110 without rotating the support 7, causing the focusing point of the laser L1 to move linearly along line M4. Simultaneously, the laser L1 is irradiated from the laser processing head 10A onto the removal area E of the object 100. At this time, the polarization direction of the laser L1 is adjusted to be along the X direction by the reflective spatial light modulator 34. That is, while moving the focusing point relative to each other along line M4 with the processing travel direction in the X direction, the laser L1 with the X direction as its polarization direction is irradiated onto the removal area E. Thus, a modified region 4 is formed in the removal area E along a pair of lines M4 on the same straight line.

[0147] As described above, in the laser processing apparatus 201, in order to achieve laser processing with the polarization direction along the processing travel direction, the driving directions of the support 7 are reduced to only the rotational direction and the Y-direction (dual-axis structure), thus suppressing the enlargement of the apparatus structure. This achieves the aforementioned effect of suppressing the enlargement of the apparatus structure and preventing cracks from easily extending from the modified region 4 along the processing travel direction. Furthermore, in the laser processing apparatus 201, the Y-direction movement mechanism 220 only moves the support 7. In this case, the number of driving axes of the laser processing head 10A is reduced, relatively increasing the design freedom of the laser processing head 10A. Additionally, there is no high-speed movement of the laser processing head 10A during laser irradiation, thus reducing the vibration of the laser L1 and the optical system.

[0148] <Variation Example>

[0149] The above is one aspect of the present invention, and is not limited to the embodiments described above.

[0150] In the above embodiments, the number of laser processing heads used is not particularly limited; a pair of laser processing heads, a single laser processing head, or three or more laser processing heads may be used. In the above embodiments, although multiple rows of modified regions 4 are formed along lines M3 and M4, it is also possible to form only one row of modified regions 4.

[0151] In the above embodiments, the order of execution of trimming and radial cutting is different. Although trimming and radial cutting are described as examples of laser processing in the above embodiments, they are not limited to this. The above embodiments are also applicable to peeling processes for removing a portion of the object 100. Peeling processing is laser processing that forms a modified region along a virtual surface inside the object. Furthermore, the above embodiments are also applicable to laser processing for cutting the object 100 along multiple lines arranged in a grid pattern.

[0152] In the above embodiments, the direction of movement of the focusing point of the laser L1 in the radial cutting process is not particularly limited. The focusing point can be moved from the inside to the outside or from the outside to the inside of the object 100 along the X direction, or the focusing point can be moved in one direction or another direction of the X direction.

[0153] In the above embodiments, the type, shape, size, number and orientation of the crystal directions of the object 100, and orientation of the main surface of the object 100 are not particularly limited. In the above embodiments, the shape of the line M3 is not particularly limited. In the above embodiments, the object 100 may be formed using a crystalline material with a crystalline structure, or alternatively, it may be formed using an amorphous material with an amorphous structure (amorphous material). The crystalline material may be either anisotropic or isotropic. For example, the object 100 may be formed using at least any one of gallium nitride (GaN), silicon (Si), silicon carbide (SiC), LiTaO3, diamond, GaOx, sapphire (Al2O3), gallium arsenide, indium phosphide, glass, and alkali-free glass.

[0154] In the above embodiment, although the back surface 100b of the object 100 is used as the laser incident surface, the surface 100a of the object 100 can also be used as the laser incident surface. In the above embodiment, the modified region 4 can be, for example, a crystalline region, a recrystallized region, or a gettering region formed inside the object 100. The crystalline region is the region that maintains the structure of the object 100 before processing. The recrystallized region is the region that solidifies as a single crystal or polycrystalline during re-solidification after evaporation, plasma treatment, or melting. The gettering region is the region that collects and captures impurities such as heavy metals, and can be formed continuously or intermittently. In addition, the above embodiment is also applicable to processing such as ablation.

[0155] The structures of the above-described embodiments and modifications are not limited to the materials and shapes described above, and can be applied to a wide variety of materials and shapes. Furthermore, the structures of the above-described embodiments or modifications can be arbitrarily applied to the structures of other embodiments or modifications.

[0156] Symbol Explanation

[0157] 1, 101, 201… Laser processing device; 4… Modification zone; 7… Support unit; 9… Control unit; 100… Object; 10A, 10B… Laser processing head (irradiation unit); 110… X-direction moving mechanism (first moving mechanism); 120… Y-direction moving mechanism (second moving mechanism); 130… Z-direction moving mechanism (third moving mechanism); C… Axis; L1, L2… Laser; M3… Line (circular line); M4… Line (straight line).

Claims

1. A laser processing apparatus, wherein is a laser processing apparatus that forms a modified region in an object by irradiating laser light while a part of a condensing region is aligned with the object, is provided with: a support portion configured to be rotatable around an axis in a vertical direction and to support the object; an irradiation portion that irradiates the laser light having a first horizontal direction as a polarization direction to the object supported by the support portion; a first moving mechanism that moves the irradiation portion in the first horizontal direction as the polarization direction; a second moving mechanism that moves at least one of the support portion and the irradiation portion in a second horizontal direction that is perpendicular to the polarization direction; and a control portion that controls operations of the support portion, the irradiation portion, the first moving mechanism, and the second moving mechanism, the control portion executes a first process of: forming the modified region in the object in a ring-like line by rotating the support portion while irradiating the laser light having the first horizontal direction as the polarization direction from the irradiation portion to the object in a state where a part of the condensing region is aligned with a position separated from the axis of the support portion in the second horizontal direction, the control portion executes a second process of: forming the modified region in the object in a straight line-like line extending in the first horizontal direction by moving the irradiation portion in the first horizontal direction by the first moving mechanism while irradiating the laser light having the first horizontal direction as the polarization direction from the irradiation portion to the object.

2. The laser processing apparatus according to claim 1, wherein the control portion: after execution of the second process, rotates the support portion to rotate the object by a certain angle and then executes the second process again.

3. The laser processing apparatus according to claim 1 or 2, wherein the second moving mechanism moves only the irradiation portion.

4. The laser processing apparatus according to claim 1 or 2, wherein the second moving mechanism moves only the support portion.

5. The laser processing apparatus according to claim 1 or 2, wherein further provided with a third moving mechanism that moves the irradiation portion in the vertical direction, the control portion further controls an operation of the third moving mechanism.

6. The laser processing apparatus according to claim 3, wherein further provided with a third moving mechanism that moves the irradiation portion in the vertical direction, the control portion further controls an operation of the third moving mechanism.

7. The laser processing apparatus according to claim 4, wherein further provided with a third moving mechanism that moves the irradiation portion in the vertical direction, the control portion further controls an operation of the third moving mechanism.

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