Laser processing equipment

Abstract

To provide a laser processing device which can change a processing width without adversely affecting process quality, and can prevent enlargement of a device.SOLUTION: A laser processing device 1 comprises: a holding unit 10 which holds a wafer 200; and a laser beam irradiation unit 20 having an oscillator 22 for irradiating the wafer 200 with laser beam 21, and an optical system 23 for guiding the laser beam 21 to the wafer 200. The optical system 23 includes: a mask member 24 having a transmission part 241 through which the laser beam 21 transmits, and a light shielding part 242 which surrounds the transmission part 241 and light-shields a part of the laser beam 21; and a mask member rotation unit 26 which rotates the mask member 24 around an axis orthogonal to an optical axis of the laser beam 21, thereby changing a light shielding area of the laser beam 21 which transmits through the transmission part 241, and changing an image formation width of the laser beam 21 to the wafer 200.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a laser processing device. [Background technology]

[0002] A known method for dicing a semiconductor wafer into individual chips involves irradiating the wafer with a laser beam along the streets to ablate and divide the wafer. For this type of laser dicing, a technique has been proposed in which the imaging shape of the laser beam is changed to a desired shape using a mask, and the processing line on the wafer is adjusted (see, for example, Patent Document 1).

[0003] However, in the above-mentioned method, in order to adjust the width of the processing line, the width of the opening formed in the mask must be changed, which requires the preparation of multiple masks, which not only increases costs but also creates the problem of requiring labor for mask replacement and adjustment.

[0004] To solve this problem, a method has been devised in which a mask with a tapered opening is moved in a direction perpendicular to the optical axis (see, for example, Patent Document 2), but when the tapered shape is transferred to the wafer, differences in the processing results occur between the outbound and inbound passes of the processing line, which may affect processing quality. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-209719 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-89094 Summary of the Invention [Problem to be solved by the invention]

[0006] Another method has been proposed in which a mask having a plurality of openings of different widths is moved in a direction perpendicular to the optical axis, but this increases the size of the mask itself, which could lead to an increase in the size of the device.

[0007] The present invention has been made in consideration of the above facts, and its purpose is to provide a laser processing device that can change the processing width without adversely affecting processing quality and that can prevent the device from becoming too large. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the laser processing apparatus of the present invention is a laser processing apparatus comprising: a holding unit for holding a wafer; an oscillator for irradiating a laser beam onto the wafer held by the holding unit; and a laser beam irradiation unit having an optical system for guiding the laser beam to the wafer and forming a focus of the laser beam at a desired location on the wafer, wherein the optical system comprises a mask member having a transmitting portion through which the laser beam passes and a light-shielding portion surrounding the transmitting portion and blocking a part of the laser beam; a control unit including a mask member rotation unit that rotates the mask member around an axis perpendicular to the optical axis of the laser beam to change a light blocking area of ​​the laser beam that passes through the transmission portion, thereby changing an imaging width of the laser beam on the wafer; a storage unit that stores in advance a correlation between the rotation angle of the mask member and the processing width at each angle; and an instruction unit that rotates the mask member to the rotation angle stored in the storage unit when a desired processing width is input; and a control unit that moves the mask member in a direction perpendicular to the optical axis of the laser beam and the rotation axis of the mask member rotation unit. Let a mobile unit; The control unit controls the moving unit so that the optical axis of the laser beam transmitted through the transmission portion is positioned at the center position of the transmission portion. It is characterized by:

[0011] In the laser processing device, the memory unit may further store the correlation between the rotation angle of the mask member and the movement amount of the moving unit, and when the desired processing width is input, the instruction unit may rotate the mask member to the rotation angle stored in the memory unit and move the mask member by the movement amount corresponding to the rotation angle.

[0012] In the laser processing apparatus, the mask member may be disposed inside a cover having a through hole that allows the laser beam to pass through. [Effects of the Invention]

[0013] The present invention has the effect of making it possible to change the processing width without adversely affecting the processing quality, and to prevent the device from becoming bulky. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a laser processing device according to the first embodiment. [Figure 2] FIG. 2 is a diagram schematically showing the configuration of the laser beam irradiation unit of the laser processing apparatus shown in FIG. [Figure 3] 3 is a side cross-sectional view showing a mask member, a cover, etc. of the laser beam irradiation unit shown in FIG. [Figure 4] FIG. 4 is a perspective view of the mask member shown in FIG. [Figure 5] FIG. 5 is a front view of the mask member shown in FIG. 4 as viewed from the oscillator side. [Figure 6] FIG. 6 is a side cross-sectional view schematically showing a state in which the mask member shown in FIG. 4 faces the oscillator. [Figure 7] FIG. 7 is a side cross-sectional view that schematically shows a state in which the mask member shown in FIG. 6 is tilted from a state in which it faces the oscillator. [Figure 8] FIG. 8 is a plan view showing the shape of the spot of the laser beam transmitted through the mask member shown in FIG. [Figure 9]FIG. 9 is a plan view showing the shape of the spot of the laser beam transmitted through the mask member shown in FIG. [Figure 10] FIG. 10 is a diagram showing imaging width change data stored in the storage unit of the control unit of the laser processing apparatus shown in FIG. [Figure 11] FIG. 11 is a diagram showing movement amount change data stored in the storage unit of the control unit of the laser processing apparatus shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configuration can be made within the scope of the gist of the present invention.

[0016] [Embodiment 1] A laser processing apparatus according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of the configuration of the laser processing apparatus according to the first embodiment. Fig. 2 is a diagram schematically showing the configuration of a laser beam irradiation unit of the laser processing apparatus shown in Fig. 1.

[0017] The laser processing apparatus 1 according to the first embodiment is an apparatus that performs laser processing on a wafer 200. The wafer 200 to be processed by the laser processing apparatus 1 according to the first embodiment is a disk-shaped semiconductor wafer, an optical device wafer, or the like, with silicon, sapphire, gallium arsenide, SiC (silicon carbide), or the like, as a substrate 201. The wafer 200 has a plurality of streets 203 that intersect with a surface 202 of the substrate 201, and devices 204 are formed in each of the areas partitioned in a grid pattern by the streets 203.

[0018] The devices 204 are, for example, integrated circuits such as ICs (Integrated Circuits) or LSIs (Large Scale Integrations), image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), or various types of memories (semiconductor storage devices). In the first embodiment, the wafer 200 is divided into individual devices 204 along the streets 203.

[0019] In embodiment 1, a disk-shaped tape 206 having a larger diameter than the wafer 200 is attached to the back surface 205 of the wafer 200, and an annular frame 207 having an inner diameter larger than the outer diameter of the wafer 200 is attached to the outer periphery of the tape 206, and the wafer 200 is supported within the inner opening of the annular frame 207.

[0020] The laser processing apparatus 1 shown in Fig. 1 is a processing apparatus that laser processes the wafer 200 by irradiating a pulsed laser beam 21 having a wavelength that is absorbed by a substrate 201 that constitutes the wafer 200 from a surface 202 of the wafer 200 along a street 203. As shown in Fig. 1, the laser processing apparatus 1 has a holding unit 10 that holds the wafer 200, a laser beam irradiation unit 20, a moving unit 30, an imaging unit 40, and a control unit 100 that is a control means.

[0021] The holding unit 10 holds the wafer 200 on a holding surface 11 that is parallel to the horizontal direction. The holding surface 11 is disk-shaped and made of porous ceramic or the like, and is connected to a vacuum suction source (not shown) via a suction path (not shown). The holding unit 10 is sucked by the vacuum suction source to suction-hold the wafer 200 placed on the holding surface 11. A plurality of clamps 12 are arranged around the holding unit 10, each clamping a frame 207 that supports the wafer 200 in an opening.

[0022] Furthermore, the holding unit 10 is rotated by the rotational movement unit 33 of the movement unit 30 around an axis that is perpendicular to the holding surface 11 and parallel to the Z-axis direction that is parallel to the vertical direction. The holding unit 10, together with the rotational movement unit 33, is moved by the X-axis movement unit 31 of the movement unit 30 in the X-axis direction (corresponding to the processing proceeding direction) that is parallel to the horizontal direction, and is moved by the Y-axis movement unit 32 in the Y-axis direction that is parallel to the horizontal direction and perpendicular to the X-axis direction. The holding unit 10 is moved by the movement unit 30 between the processing region below the laser beam irradiation unit 20 and a carry-in / out region that is away from below the laser beam irradiation unit 20 and where the wafer 200 is carried in and out.

[0023] The laser beam irradiation unit 20 is a laser beam irradiation means that focuses and irradiates a pulsed laser beam 21 onto the wafer 200 held by the holding unit 10. In the first embodiment, a part of the laser beam irradiation unit 20 is moved in the Z-axis direction by a Z-axis moving unit 34 that is disposed on an upright wall 3 that stands upright from the apparatus main body 2, as shown in FIG.

[0024] The laser beam irradiation unit 20 irradiates a laser beam 21 having a wavelength that is absorbed by the substrate 201 of the wafer 200 held in the holding unit 10, thereby laser processing the wafer 200. As shown in Fig. 2, the laser beam irradiation unit 20 has an oscillator 22 that emits a pulsed laser beam 21 having a wavelength that is absorbed by the substrate 201 of the wafer 200, and an optical system 23 that guides the laser beam 21 to the wafer 200 held in the holding unit 10 and forms a focus 211 of the laser beam 21 at a desired location on the wafer 200.

[0025] The optical system 23 includes a focusing lens 231 that focuses the laser beam 21 emitted from the oscillator 22 onto the surface 202 of the wafer 200 held on the holding surface 11 of the holding unit 10, a reflecting mirror 232 that reflects the laser beam 21 emitted from the oscillator 22 toward the focusing lens 231, and a relay lens 233 that guides the laser beam 21 emitted from the oscillator 22 to the reflecting mirror 232.

[0026] The condenser lens 231 is disposed at a position facing the holding surface 11 of the holding unit 10 in the Z-axis direction. The condenser lens 231 is a focusing optical element that focuses and irradiates the pulsed laser beam 21 onto the wafer 200 held by the holding unit 10. The condenser lens 231 transmits the laser beam 21 emitted from the oscillator 22 and focuses the laser beam 21 at a focal point 211 (shown in FIG. 2, etc.). In the first embodiment, the condenser lens 231 focuses the focal point 211 of the laser beam 21 onto the surface 202 of the wafer 200 held on the holding surface 11 of the holding unit 10.

[0027] 2, the optical system 23 of the laser beam irradiation unit 20 includes a mask member 24, a cover 25, a mask member rotation unit 26, and a moving unit 27. Next, the mask member 24 will be described. FIG. 3 is a side cross-sectional view showing the mask member and cover of the laser beam irradiation unit shown in FIG. 2. FIG. 4 is a perspective view of the mask member shown in FIG. 3. FIG. 5 is a front view of the mask member shown in FIG. 4, seen from the oscillator side. FIG. 6 is a side cross-sectional view schematically showing the mask member shown in FIG. 4 facing the oscillator. FIG. 7 is a side cross-sectional view schematically showing the mask member shown in FIG. 6 tilted from the state facing the oscillator. FIG. 8 is a plan view showing the shape of the spot of the laser beam transmitted through the mask member shown in FIG. 6. FIG. 9 is a plan view showing the shape of the spot of the laser beam transmitted through the mask member shown in FIG. 7.

[0028] In the first embodiment, the mask member 24 is disposed between the oscillator 22 and the relay lens 233. As shown in FIGS. 3, 4, and 5, the mask member 24 has a transmitting portion 241 through which the laser beam 21 passes and a light-shielding portion 242 that surrounds the transmitting portion 241 and blocks a portion of the laser beam 21. In the first embodiment, the mask member 24 is formed in a rectangular shape whose longitudinal direction is parallel to the X-axis direction, and the transmitting portion 241 is formed in the center. In the first embodiment, the mask member 24 has the transmitting portion 241 formed as a rectangular hole whose longitudinal direction is parallel to the X-axis direction and that transmits the laser beam 21, and the periphery of the transmitting portion 241 is made of a material that blocks the laser beam 21 to form the light-shielding portion 242. In the first embodiment, the mask member 24 has a reflective film 243 that reflects the laser beam 21 formed on the surface of the light-shielding portion 242 that faces the oscillator 22. In the first embodiment, the width 244 (shown in FIG. 5) of the transmitting portion 241 in the Z-axis direction is 1 mm.

[0029] 6 and 7, the mask member 24 has a transmitting portion 241 that transmits the laser beam 21 emitted by the oscillator 22 and allows the laser beam 21 to be guided to the wafer 200 by the relay lens 233, the reflecting mirror 232, and the condenser lens 231. As shown in Figures 6 and 7, the mask member 24 has a light-shielding portion 242 that shields the laser beam 21 and prevents the laser beam 21 from being guided to the wafer 200 by the relay lens 233, the reflecting mirror 232, and the condenser lens 231. Note that a region 212 of the laser beam 21 that is shielded by the light-shielding portion 242 (shown by parallel diagonal lines in Figure 5) will be referred to as a light-shielded region hereinafter.

[0030] The mask member 24 transmits the laser beam 21 emitted by the oscillator 22 through the transmitting portion 241 and blocks the laser beam 21 through the light-shielding portion 242, thereby shaping the laser beam 21 emitted from the oscillator 22 so that a spot 28 (shown in FIGS. 8 and 9) of the focal point 211 of the laser beam 21 has a rectangular shape. In the first embodiment, the mask member 24 shapes the spot 28 of the focal point 211 of the laser beam 21 on the surface 202 of the wafer 200 held by the holding unit 10 into a rectangle in which the longitudinal direction of the spot 28 is parallel to the Y-axis direction and the lateral direction of the spot 28 is parallel to the X-axis direction, as shown in FIGS. Hereinafter, the width 281 of the spot 28 in the longitudinal direction (corresponding to the processing width) will be referred to as the imaging width.

[0031] In the first embodiment, the cover 25 is disposed between the oscillator 22 and the relay lens 233. As shown in Fig. 3, the cover 25 is made of a material that blocks the laser beam 21, and is formed in a box shape with a through-hole 251 that allows the laser beam 21 to pass through. The cover 25 houses the mask member 24 inside. In this way, the mask member 24 is disposed inside the cover 25 that has the through-hole 251 that allows the laser beam 21 to pass through.

[0032] The mask member rotation unit 26 rotates the mask member 24 around an axis 245 (shown in FIGS. 4 and 5 ) parallel to the X-axis direction perpendicular to the optical axis 213 of the laser beam 21. By rotating the mask member 24 around the axis 245 parallel to the X-axis direction perpendicular to the optical axis 213 of the laser beam 21, the mask member rotation unit 26 changes the light-shielded region 212 that is shielded by the light-shielding portion 242 of the laser beam 21 that transmits through the transmitting portion 241, thereby changing the imaging width 281 of the focus 211 of the laser beam 21 on the wafer 200. In the first embodiment, the mask member rotation unit 26 rotates the mask member 24 around the axis 245 from the state shown in FIG. 6 in which the surface of the reflective film 243 is perpendicular to the optical axis 213.

[0033] The laser beam irradiation unit 20 irradiates the wafer 200 held in the holding unit 10 with a laser beam 21 of a wavelength that is absorbed by the substrate 201 of the wafer 200, thereby performing an ablation process in which a portion of the substrate 201 of the wafer 200 is sublimated and a processed groove (not shown) is formed.

[0034] The moving unit 27 moves the mask member 24 in a direction perpendicular to both the optical axis 213 of the laser beam 21 emitted by the oscillator 22 and an axis 245 that is parallel to the X-axis direction and is the rotation axis of the mask member rotation unit 26. In the first embodiment, the moving unit 27 moves the cover 25, the mask member rotation unit 26, and the mask member 24 in the Z-axis direction. The moving unit 27 includes a well-known ball screw that is rotatable about its axis, a well-known pulse motor that rotates the ball screw about its axis, and well-known guide rails that support the cover 25, the mask member rotation unit 26, and the mask member 24 so that they are movably in the Z-axis direction.

[0035] The moving unit 30 relatively moves the holding unit 10 and the focal point 211 of the laser beam 21 emitted by the laser beam irradiation unit 20 around axes parallel to the X-axis direction, Y-axis direction, and Z-axis direction. The X-axis direction and the Y-axis direction are perpendicular to each other and parallel to the holding surface 11 (i.e., the horizontal direction). The moving unit 30 includes an X-axis moving unit 31 which is a processing feed unit that moves the holding unit 10 in the X-axis direction, a Y-axis moving unit 32 which is an indexing feed unit that moves the holding unit 10 in the Y-axis direction, a rotational moving unit 33 that rotates the holding unit 10 around an axis parallel to the Z-axis direction, and a Z-axis moving unit 34 that moves a part of the laser beam irradiation unit 20 in the Z-axis direction.

[0036] The Y-axis moving unit 32 is a unit that relatively indexes and moves the holding unit 10 and the focal point 211 of the laser beam 21 of the laser beam irradiation unit 20. In the first embodiment, the Y-axis moving unit 32 is installed on the device body 2 of the laser processing device 1. The Y-axis moving unit 32 supports the moving plate 4 that supports the X-axis moving unit 31 so that the moving plate 4 is movable in the Y-axis direction.

[0037] The X-axis moving unit 31 is a feed means for relatively feeding the holding unit 10 and the focal point 211 of the laser beam 21 of the laser beam irradiation unit 20 for processing. The X-axis moving unit 31 is installed on the moving plate 4. The X-axis moving unit 31 supports a second moving plate 5, which supports a rotational moving unit 33 that rotates the holding unit 10 around an axis parallel to the Z-axis direction, so as to be movable in the X-axis direction. The second moving plate 5 supports the rotational moving unit 33 and the holding unit 10. The rotational moving unit 33 supports the holding unit 10.

[0038] The X-axis moving unit 31, the Y-axis moving unit 32, and the Z-axis moving unit 34 each include a well-known ball screw rotatably mounted about its axis, a well-known pulse motor for rotating the ball screw about its axis, and well-known guide rails for supporting the moving plates 4 and 5 and the condenser lens 231 included in the laser beam irradiation unit 20 so that they can move in the X-axis, Y-axis, or Z-axis direction. The rotational moving unit 33 includes a motor for rotating the holding unit 10 about its axis, etc.

[0039] The laser processing device 1 also includes an X-axis position detection unit (not shown) for detecting the position of the holding unit 10 in the X-axis direction, a Y-axis position detection unit (not shown) for detecting the position of the holding unit 10 in the Y-axis direction, and a Z-axis position detection unit (not shown) for detecting the position of the laser beam irradiation unit 20 in the Z-axis direction. Each position detection unit outputs the detection result to the control unit 100.

[0040] The imaging unit 40 captures an image of the wafer 200 held by the holding unit 10. The imaging unit 40 includes an imaging element such as a CCD (Charge Coupled Device) imaging element or a CMOS (Complementary MOS) imaging element that captures an image of an object facing the objective lens in the Z-axis direction. In the first embodiment, the imaging unit 40 is attached by the laser beam irradiation unit 20, and is disposed at a position where the objective lens is aligned with the condenser lens 231 along the X-axis direction.

[0041] The imaging unit 40 acquires the image captured by the imaging element and outputs the acquired image to the control unit 100. The imaging unit 40 also captures an image of the wafer 200 held on the holding surface 11 of the holding unit 10 and acquires an image for performing alignment between the wafer 200 and the laser beam irradiation unit 20.

[0042] The control unit 100 controls each of the above-mentioned components of the laser processing apparatus 1, causing the laser processing apparatus 1 to perform laser processing operations on the wafer 200. The control unit 100 is a computer having an arithmetic processing device with a microprocessor such as a CPU (central processing unit), a storage device with memory such as a ROM (read only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing device of the control unit 100 performs arithmetic processing in accordance with a computer program stored in the storage device, and outputs control signals for controlling the laser processing apparatus 1 to the above-mentioned components of the laser processing apparatus 1 via the input / output interface device, thereby realizing the functions of the control unit 100.

[0043] The laser processing apparatus 1 also includes a display unit 110, which is a display means configured with a liquid crystal display device or the like that displays the status of the processing operation, images, etc., and an input unit 120, which is an input means used by the operator to input processing conditions, etc. The display unit 110 and the input unit 120 are connected to the control unit 100. The input unit 120 is configured with at least one of a touch panel provided on the display unit 110 and an external input device such as a keyboard.

[0044] As shown in Fig. 1, the control unit 100 includes a storage unit 101 and an instruction unit 102. Fig. 10 is a diagram showing imaging width change data stored in the storage unit of the control unit of the laser processing apparatus shown in Fig. 1. Fig. 11 is a diagram showing movement amount change data stored in the storage unit of the control unit of the laser processing apparatus shown in Fig. 1.

[0045] The storage unit 101 stores in advance imaging width changing data 103 shown in Fig. 10 and movement amount changing data 104 shown in Fig. 11. The imaging width changing data 103 indicates the correlation between the rotation angle of the mask member 24 and the imaging width 281 at each rotation angle. The horizontal axis in Fig. 10 indicates the rotation angle of the mask member 24, and the vertical axis in Fig. 10 indicates the imaging width. The rotation angle of the mask member 24 on the horizontal axis in Fig. 10 indicates the rotation angle around the axis 245 of the mask member 24 from the state shown in Fig. 6, with the state facing the oscillator 22 shown in Fig. 6 being set to 0 degrees.

[0046] The movement amount changing data 104 indicates the correlation between the rotation angle of the mask member 24 and the movement amount of the moving unit 27, and is used to position the optical axis 213 of the laser beam 21 transmitted through the transmitting portion 241 at the center of the transmitting portion 241 regardless of the rotation angle of the mask member 24. The horizontal axis in Fig. 11 indicates the rotation angle of the mask member 24, and the vertical axis in Fig. 11 indicates the movement amount.

[0047] The rotation angle of the mask member 24 on the horizontal axis in Fig. 11 indicates the rotation angle around the axis 245 of the mask member 24 from the state shown in Fig. 6, with the state facing the oscillator 22 shown in Fig. 6 being set to 0 degrees. The movement amount of the mask member 24 on the vertical axis in Fig. 11 indicates the movement amount of the mask member 24 etc. in the Z axis direction from the state shown in Fig. 6, with the state facing the oscillator 22 shown in Fig. 6 being set to 0. In other words, by positioning the mask member 24 at a position where the movement amount of the mask member 24 on the vertical axis in Fig. 11 corresponds to the rotation angle of the mask member 24 on the horizontal axis in Fig. 11, the optical axis 213 of the laser beam 21 transmitted by the transmission portion 241 is positioned at the center of the transmission portion 241.

[0048] The instruction unit 102 controls the mask member rotation unit 26 to rotate and position the mask member 24 at a rotation angle corresponding to the input imaging width 281 of the imaging width modification data 103 stored in the storage unit 101 when a desired imaging width 281 for laser processing the wafer 200 is input from the input unit 120 or the like. For example, when the imaging width 281-1 shown in FIG. 10 is input, the instruction unit 102 positions the mask member 24 at a rotation angle 300-1 corresponding to the input imaging width 281-1 of the imaging width modification data 103. When the imaging width 281-2 shown in FIG. 281-2 is input, the instruction unit 102 positions the mask member 24 at a rotation angle 300-2 corresponding to the input imaging width 281-2 of the imaging width modification data 103.

[0049] Furthermore, the instruction unit 102 references the movement amount change data 104, extracts the movement amount according to the rotation angle corresponding to the input imaging width 281 of the imaging width change data 103, and controls the movement unit 27 to move the mask member 24 and the like by the movement amount according to the rotation angle of the movement amount change data 104. For example, when the mask member 24 is positioned at rotation angle 300-1, the instruction unit 102 moves the mask member 24 by movement amount 400-1 corresponding to rotation angle 300-1 of the movement amount change data 104. When the mask member 24 is positioned at rotation angle 300-2, the instruction unit 102 moves the mask member 24 by movement amount 400-2 corresponding to rotation angle 300-2 of the movement amount change data 104.

[0050] The functions of the storage unit 101 are realized by the above-mentioned storage device, and the functions of the instruction unit 102 are realized by the arithmetic processing unit performing arithmetic processing in accordance with the computer program stored in the storage device.

[0051] Next, the processing operation of the laser processing apparatus 1 having the above-described configuration will be described. In the laser processing apparatus 1, the control unit 100 accepts and registers processing conditions input by an operator, and the back surface 205 side of the wafer 200 is placed on the holding surface 11 of the holding unit 10 positioned in the carry-in / out area. The processing conditions include the imaging width 281 described above. The laser processing apparatus 1 starts processing operation when the control unit 100 accepts an instruction to start processing operation from the operator.

[0052] In the processing operation, the instruction section 102 of the control unit 100 of the laser processing apparatus 1 causes the mask member rotation unit 26 to rotate the mask member 24 to a rotation angle corresponding to the desired imaging width 281 included in the processing conditions input in the imaging width changing data 103, and also causes the mask member 24 to move to the moving unit 27 by a movement amount corresponding to the rotation angle of the movement amount changing data 104. Also, in the processing operation, the control unit 100 of the laser processing apparatus 1 suction-holds the wafer 200 on the holding surface 11 of the holding unit 10, and causes the clamp section 12 to clamp the frame 207.

[0053] In the processing operation, the control unit 100 controls the moving unit 30 to move the holding unit 10 to the processing area, the imaging unit 40 captures an image of the wafer 200 held by suction in the holding unit 10, and performs alignment. In the processing operation, the laser processing apparatus 1 sets the focal point 211 of the laser beam irradiation unit 20 on the surface of the substrate 201, and irradiates the wafer 200 with a pulsed laser beam 21 along the street 203 from the surface 202 side of the wafer 200 while moving the holding unit 10 and the focal point 211 of the laser beam irradiation unit 20 relatively along the street 203.

[0054] In embodiment 1, during the processing operation, the laser processing device 1 moves the holding unit 10 and irradiates the laser beam 21 along the street 203 at the center of the width of each street 203 of the wafer 200 held by suction in the holding unit 10, thereby performing ablation processing on each street 203 and dividing the wafer into individual devices 204.

[0055] In the processing operation, the laser processing apparatus 1 performs ablation processing on all the streets 203 and divides the wafer 200 into individual devices 204, then stops irradiating the laser beam 21 and moves the holding unit 10 to the carry-in / out area. In the processing operation, the laser processing apparatus 1 positions the holding unit 10 in the carry-in / out area, stops suction holding of the wafer 200 by the holding unit 10, releases the clamping of the frame 207 of the clamp section 12, and ends the processing operation.

[0056] The laser processing apparatus 1 according to the first embodiment described above is configured such that the mask member rotation unit 26 can change the image width 281 processed on the wafer 200 by rotating the mask member 24 having the transmitting portion 241 and the light-shielding portion 242 about an axis 245 parallel to the X-axis direction perpendicular to the optical axis 213 of the laser beam 21. This allows the laser processing apparatus 1 to reduce the number of steps required for mask replacement and adjustment, and can prevent differences in the processing results between moving the laser beam 21 and the wafer 200 in one direction relative to the other when irradiating the laser beam 21, i.e., between the forward and backward movements. Furthermore, because the laser processing apparatus 1 changes the image width 281 by rotating the mask member 24 having the transmitting portion 241, the size of the mask member 24 itself can be reduced, thereby preventing the apparatus from becoming bulky.

[0057] As a result, the laser processing apparatus 1 has the effect of being able to change the imaging width 281 without adversely affecting the processing quality, and preventing the apparatus from becoming bulky.

[0058] The present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the gist of the present invention. [Explanation of symbols]

[0059] 1. Laser processing equipment 10 Holding Unit 20 Laser beam irradiation unit 21 Laser Beam 22 Oscillator 23 Optical system 24 Mask material 25 Cover 26 Mask material rotation unit 27 Mobile Unit 100 control unit 101 Storage section 102 Instruction section 103 Data for changing the imaging width (correlation between the rotation angle of the mask member and the processing width at each angle) 104 Data for changing the amount of movement (correlation between the rotation angle of the mask member and the amount of movement of the moving unit) 200 wafers 211 Focus 212 Shading area 213 Optical axis 241 Transparent part 242 Light blocking section 245 Axis center (rotating axis) 251 Through hole 281, 281-1, 281-2 Imaging width (processing width) 300-1,300-2 rotation angle 400-1,400-2 Movement

Claims

1. a holding unit that holds the wafer; a laser beam irradiation unit having an oscillator for irradiating a laser beam onto the wafer held by the holding unit, and an optical system for guiding the laser beam to the wafer and forming a focus of the laser beam at a desired location on the wafer; A laser processing device comprising: The optical system comprises: a mask member having a transmitting portion through which the laser beam passes and a light-shielding portion surrounding the transmitting portion and blocking a part of the laser beam; a mask member rotation unit that rotates the mask member around an axis perpendicular to the optical axis of the laser beam to change a light-shielding region of the laser beam that passes through the transmission portion, thereby changing an imaging width of the laser beam on the wafer; a control unit including a storage unit that stores in advance the correlation between the rotation angle of the mask member and the processing width at each angle, and an instruction unit that, when a desired processing width is input, rotates the mask member to the rotation angle stored in the storage unit; a moving unit that moves the mask member in a direction perpendicular to the optical axis of the laser beam and the rotation axis of the mask member rotating unit, The control unit controls the moving unit so that the optical axis of the laser beam transmitted through the transmission portion is positioned at the center position of the transmission portion. Laser processing equipment.

2. The storage unit further storing a correlation between the rotation angle of the mask member and the movement amount of the movement unit; The instruction unit When a desired processing width is input, the mask member is rotated to the rotation angle stored in the storage unit, The mask member is moved by an amount corresponding to the rotation angle. The laser processing device according to claim 1.

3. the mask member is disposed inside a cover having a through hole that allows the laser beam to pass through.

3. The laser processing device according to claim 1 or 2.

Images