Laser light irradiation device

Abstract

To achieve high productivity with a simple device configuration.SOLUTION: In a laser beam irradiation device 1, a laser beam irradiation unit 20 includes: a laser light source for emitting a laser beam; a spatial light modulator for modulating the laser beam emitted from the laser light source according to a phase pattern, and emitting the laser beam; and imaging means for imaging the laser beam modulated by the spatial light modulator, and irradiating a plate-like object with the laser beam, wherein a control unit 90 has: a phase pattern storage part 91 for storing a plurality of phase patterns having different positions irradiated with the laser beam in a plane of the plate-like object when being displayed on the spatial light modulator; and a phase pattern control part 92 for switching the phase pattern displayed on the spatial light modulator to a predetermined phase pattern out of the plurality of phase patterns stored in the phase pattern storage part 91, and the phase pattern control part 92 switches the phase pattern displayed on the spatial light modulator, and thereby secondarily scans the plane of the plate-like object with the laser beam.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laser light irradiation device.

Background Art

[0002] As a laser light irradiation device that irradiates an object with laser light, for example, the device described in Patent Document 1 is known. In such a laser light irradiation device, the laser light generated by the laser light source is modulated by a spatial light modulator and then condensed onto the object by an objective lens. When changing the irradiation range of the laser light irradiated on the object by the laser light irradiation device of Patent Document 1, the irradiation range is changed using scanning means such as a galvanometer scanner or a MEMS scanner as the irradiation range changing means.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, this method that requires scanning means makes the device configuration somewhat complicated and causes the device to become bulky. Also, for example, the method of changing the irradiation range by moving the processing table on which the object is placed has a different problem that it takes time to move the processing table. Further, for example, the method of reducing the movement by increasing the irradiation range cannot ensure the power density in the irradiation range because the power that can be input is limited from the viewpoint of the light resistance of the spatial light modulator, and thus it is impossible to achieve.

[0005] The present invention has been made in view of such problems, and an object thereof is to provide a laser light irradiation device that can achieve high productivity with a simple device configuration. [Means for solving the problem]

[0006] To solve the above-mentioned problems and achieve the objective, the present invention provides a laser beam irradiation device comprising: a holding table for holding a plate-shaped object; a laser beam irradiation unit for irradiating a plate-shaped object held on the holding table with laser beam; and a control unit for controlling the components, wherein the laser beam irradiation unit includes a laser light source for emitting the laser beam; a spatial light modulator for modulating and emitting the laser beam emitted from the laser light source according to a phase pattern; and an imaging means for imaging the laser beam modulated by the spatial light modulator and irradiating a plate-shaped object with it, wherein the control unit includes a phase pattern storage unit for storing a plurality of phase patterns in which the positions where the laser beam is irradiated on the surface of the plate-shaped object are different when displayed on the spatial light modulator; and a phase pattern control unit for switching the phase pattern to be displayed on the spatial light modulator to a predetermined phase pattern from the plurality of phase patterns stored in the phase pattern storage unit, wherein the phase pattern control unit switches the phase pattern to be displayed on the spatial light modulator. By switching the irradiation range of the laser beam from a first region within the surface of the plate-like object to a second region that does not include the first region, and by sequentially switching the phase pattern, the irradiation range of the laser beam is sequentially switched within the surface of the plate-like object. The laser beam is characterized by its ability to be scanned two-dimensionally within the plane of the plate-like object.

[0007] Furthermore, the laser beam irradiation device of the present invention may further include a moving unit that moves the holding table and the imaging point of the laser beam relative to each other.

[0008] Furthermore, in the laser light irradiation device of the present invention, the plate-like object is a substrate on which a plurality of semiconductor chips having bumps on one surface are mounted via the bumps, and the plurality of phase patterns stored in the phase pattern storage unit include each phase pattern in which the position where the laser light is irradiated when displayed on the spatial light modulator corresponds to the region of each semiconductor chip mounted on the substrate, and the phase pattern control unit switches the phase pattern to be displayed on the spatial light modulator by By switching the irradiation range of the laser beam from the region corresponding to the first semiconductor chip to the region corresponding to a second semiconductor chip different from the first semiconductor chip, and by sequentially switching the phase pattern, the irradiation range of the laser beam is sequentially switched to the region corresponding to each semiconductor chip. Alternatively, the laser beam may be scanned two-dimensionally within the plane of the substrate in a region corresponding to the semiconductor chip, while the bumps included in the irradiated area of ​​the laser beam are reflowed.

[0009] Furthermore, in the laser reflow method of the present invention, the imaging means may be the imaging function of the spatial light modulator. [Effects of the Invention]

[0010] This invention enables high productivity with a simple device configuration. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a perspective view showing an example of the configuration of a laser light irradiation device according to an embodiment. [Figure 2] Figure 2 is a perspective view showing an example of a plate-shaped object that is irradiated with laser light by the laser light irradiation device shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of the main part of the plate-like object shown in Figure 2. [Figure 4] Figure 4 shows an example of the optical system configuration of the laser light irradiation device shown in Figure 1. [Figure 5] Figure 5 is a perspective view showing the state in which laser light modulated by the first phase pattern is imaged onto a plate-like object. [Figure 6] Figure 6 is a perspective view showing the state in which laser light modulated by the second phase pattern is imaged onto a plate-like object. [Figure 7] Figure 7 is a perspective view showing the state in which laser light modulated by the third phase pattern is imaged onto a plate-like object. [Figure 8] Figure 8 is a perspective view showing the state in which laser light modulated by the fourth phase pattern is imaged onto a plate-like object. [Figure 9] Figure 9 is a cross-sectional view of the main part of the plate-like object shown in Figures 5 and 6. [Modes for carrying out the invention]

[0012] 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 those skilled in the art, and those that are substantially the same. Moreover, the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the present invention.

[0013] [Embodiment] A laser light irradiation device 1 according to an embodiment of the present invention will be described based on the drawings. Figure 1 is a perspective view showing an example of the configuration of the laser light irradiation device 1 according to the embodiment. Figure 2 is a perspective view showing an example of a plate-shaped object 100 to be irradiated with laser light 21 by the laser light irradiation device 1 shown in Figure 1. Figure 3 is a cross-sectional view of the main part of the plate-shaped object 100 shown in Figure 2. Figure 4 is a diagram showing an example of the configuration of the optical system of the laser light irradiation device 1 shown in Figure 1. In the following description, the X-axis direction is a single direction in the horizontal plane. The Y-axis direction is a direction perpendicular to the X-axis direction in the horizontal plane. The Z-axis direction is a direction perpendicular to both the X-axis and Y-axis directions.

[0014] The laser beam irradiation device 1 of this embodiment comprises a holding table 10, a laser beam irradiation unit 20, a moving unit 30, an imaging unit 70, a display unit 80, and a control unit 90. The laser beam irradiation device 1 is a device that irradiates a plate-shaped object 100 (see Figures 2 and 3) held on the holding table 10 with laser beam 21 (see Figure 4).

[0015] In an embodiment, the plate-like object 100 shown in FIGS. 2 and 3 includes a substrate 110 and a semiconductor chip 120 placed on the substrate 110 via bumps 130. By reflowing the bumps 130 with the laser beam 21, the semiconductor chip 120 is to be flip-mounted with respect to the substrate 110. That is, the laser beam irradiation device 1 of the embodiment is a device capable of connecting the semiconductor chip 120 to the substrate 110 by irradiating the semiconductor chip 120 placed on the substrate 110 of the plate-like object 100 held on the holding table 10 with the laser beam 21 to reflow the bumps 130.

[0016] In the embodiment, the substrate 110 is rectangular. The substrate 110 is, for example, a PCB substrate (Printed Circuit Board) or a device wafer before being divided into chips. A plurality of semiconductor chips 120 are arranged on the surface 111 side of the substrate 110 via bumps 130. The semiconductor chip 120 has one or more bumps 130 on the surface 121. The bump 130 is a protruding terminal provided on the surface 121 of the semiconductor chip 120.

[0017] The semiconductor chip 120 is connected to the electrodes on the substrate 110 when the substrate 110 and the semiconductor chip 120 are heated and the bumps 130 melt. Note that, in addition to the case where the semiconductor chip 120 in the embodiment is arranged on the substrate 110 via the bumps 130, the plate-like object 100 may be one in which a plurality of semiconductor chips 120 are stacked and bumps 130 exist between the respective semiconductor chips 120.

[0018] The holding table 10 shown in FIG. 1 holds the plate-like object 100 on the holding surface 11. The holding surface 11 is a disk shape formed from a porous ceramic or the like. In the embodiment, the holding surface 11 is a plane parallel to the horizontal direction. The holding surface 11 is connected to a vacuum suction source via a vacuum suction path, for example. The holding table 10 sucks and holds the plate-like object 100 placed on the holding surface 11.

[0019] The plate-shaped object 100 is held on the holding table 10 with the semiconductor chip 120 placed on the substrate 110. At this time, the semiconductor chip 120 is placed on the surface 111 side of the substrate 110, which is facing upwards, via the bumps 130, with one side (surface 121) having the bumps 130 facing downwards.

[0020] The holding table 10 is rotated by the rotating unit 13 around an axis parallel to the Z-axis direction. The rotating unit 13 is supported by the X-axis direction moving plate 14. The rotating unit 13 and the holding table 10 are moved in the X-axis direction by the X-axis direction moving unit 40 of the moving unit 30 via the X-axis direction moving plate 14. The rotating unit 13 and the holding table 10 are moved in the Y-axis direction by the Y-axis direction moving unit 50 of the moving unit 30 via the X-axis direction moving plate 14, the X-axis direction moving unit 40, and the Y-axis direction moving plate 15.

[0021] The laser light irradiation unit 20 is a unit that irradiates a plate-shaped object 100 held on a holding table 10 with laser light 21. As shown in Figure 4, the laser light irradiation unit 20 includes a laser light source 22, a uniform irradiation unit 23, a light guide unit 24, a spatial light modulator 25, and an imaging means 26.

[0022] The laser light source 22 emits laser light 21. The laser light source 22 includes, for example, a fiber laser, a single light source having a single laser diode (LD), or a multi-light source having multiple laser diodes arranged. The laser light 21 emitted from the laser light source 22 is a continuous wave (CW) with a wavelength that is absorbed by the plate-shaped object 100 (semiconductor chip 120).

[0023] The uniform irradiation unit 23 is positioned downstream of the laser light source 22. The uniform irradiation unit 23 is intended to form a uniform irradiation surface on the spatial light modulator 25, which will be described later, by the laser light 21 emitted from the uniform irradiation unit 23. On this uniform irradiation surface, the power density of the laser light 21 becomes uniform.

[0024] The uniform irradiation unit 23 is particularly preferable to be provided when the laser light source 22 is a multi-light source. Even in the case of a single light source, the uniform irradiation unit 23 is preferable to be provided in order to achieve a perfect top-hat distribution in the case of a light source having a Gaussian distribution, and also preferable to be provided in order to achieve a more perfect top-hat distribution in the case of a light source having a top-hat distribution.

[0025] As the uniform illumination unit 23, for example, a uniform illumination surface can be formed by a combination of a collimating lens and an aspherical lens; a uniform illumination surface can be formed by a combination of a collimating lens, a DOE (Diffractive Optical Element), and a focusing lens; a uniform illumination surface can be formed by a combination of a rod lens (a cylindrical member made of glass) or a light pipe (a hollow cylindrical member surrounded by mirrors, also called a homogenizer rod) and a light guide unit (a relay lens or optical fiber); or a uniform illumination surface can be formed by a combination of a collimating lens, a first lens array and a second lens array (a bundle of multiple rod lenses arranged in an array, or lenses processed into an array shape) and a focusing lens.

[0026] The light guide unit 24 is a unit for transferring light from the uniformly irradiated surface formed by the uniform irradiation unit 23 to the spatial light modulator 25. If the laser light irradiation unit 20 does not include the uniform irradiation unit 23, the light guide unit 24 transfers direct light from the laser light source 22 to the spatial light modulator 25. The light guide unit 24 is composed of, for example, an optical fiber or a relay lens (composite lens).

[0027] The spatial light modulator 25 is positioned between the laser light source 22 and the imaging means 26. The spatial light modulator 25 includes a spatial light modulation element and modulates and emits the laser light 21 emitted from the laser light source 22 according to the phase pattern to be displayed. The spatial light modulator 25 modulates the laser light 21 by controlling the spatial density distribution of the intensity (power density) of the emitted laser light 21, and is a so-called SLM (Spatial Light Modulator).

[0028] The spatial light modulator 25 changes the position of the irradiated area of ​​the plate-shaped object 100 when the laser beam 21 is irradiated onto the plate-shaped object 100 by changing the phase pattern displayed. As the spatial light modulator 25, well-known SLM devices such as reflective liquid crystal on silicon (LCOS), transmissive liquid crystal panel (LCP), deformable mirror, and digital micro-mirror device (DMD) can be used. In this embodiment, the spatial light modulator 25 is an LCOS.

[0029] The imaging means 26 images the incident laser light 21 onto the irradiated surface of the plate-shaped object 100. The laser light irradiation unit 20 of this embodiment uses the imaging means 26 to image the laser light 21 onto the area corresponding to the back surface 122 of the semiconductor chip 120 on the plate-shaped object 100 on the holding table 10. The laser light irradiation unit 20 may irradiate multiple semiconductor chips 120 simultaneously. The imaging means 26 of this embodiment includes an imaging system 27, a magnifying imaging lens 28, and a telecentric lens 29.

[0030] The imaging system 27 consists of an imaging lens made up of a single lens or a set of lenses. In the example shown in Figure 5, it is composed of a biconvex lens and a biconcave lens arranged in sequence. The imaging system 27 may be omitted if the spatial light modulator 25 also functions as the imaging system 27 (imaging lens) through the spatial light modulation element.

[0031] The magnifying image lens 28 magnifies the image (conjugate image) formed by the imaging system 27 and projects it onto the illuminated surface of the plate-shaped object 100. The magnifying image lens 28 may be omitted.

[0032] The telecentric lens 29 is used to cause the laser beam 21 to be incident perpendicularly to the irradiated surface of the plate-shaped object 100, that is, to cause it to be incident parallel to the optical axis. The imaging system 27 can also be configured as the telecentric lens 29, or the optical system can be configured without the telecentric lens 29.

[0033] The moving unit 30 shown in Figure 1 is a unit that moves the holding table 10 and the laser beam irradiation unit 20 relative to each other. The moving unit 30 includes an X-axis moving unit 40, a Y-axis moving unit 50, and a Z-axis moving unit 60.

[0034] The X-axis movement unit 40 is a unit that moves the holding table 10 and the laser beam irradiation unit 20 relative to each other in the X-axis direction. In the embodiment, the X-axis movement unit 40 moves the holding table 10 in the X-axis direction. In the embodiment, the X-axis movement unit 40 is installed on the main body 2 of the laser beam irradiation device 1.

[0035] The X-axis movement unit 40 supports the X-axis movement plate 14 so that it can move in the X-axis direction. In this embodiment, the X-axis movement unit 40 includes a well-known ball screw 41, a well-known pulse motor 42, and a well-known guide rail 43. The ball screw 41 is rotatably mounted around its axis. The pulse motor 42 rotates the ball screw 41 around its axis. The guide rail 43 supports the X-axis movement plate 14 so that it can move in the X-axis direction. The guide rail 43 is fixedly mounted to the Y-axis movement plate 15.

[0036] The Y-axis movement unit 50 is a unit that moves the holding table 10 and the laser beam irradiation unit 20 relative to each other in the Y-axis direction. In the embodiment, the Y-axis movement unit 50 moves the holding table 10 in the Y-axis direction. In the embodiment, the Y-axis movement unit 50 is installed on the main body 2 of the laser beam irradiation device 1.

[0037] The Y-axis movement unit 50 supports the Y-axis movement plate 15 so that it can move freely in the Y-axis direction. In this embodiment, the Y-axis movement unit 50 includes a well-known ball screw 51, a well-known pulse motor 52, and a well-known guide rail 53. The ball screw 51 is rotatably mounted around its axis. The pulse motor 52 rotates the ball screw 51 around its axis. The guide rail 53 supports the Y-axis movement plate 15 so that it can move freely in the Y-axis direction. The guide rail 53 is fixedly mounted to the device body 2.

[0038] The Z-axis movement unit 60 is a unit that moves the imaging point of the laser light 21, which is imaged by the imaging means 26 shown in Figure 4, in the optical axis direction. The optical axis direction is the Z axis direction, which is perpendicular to the holding surface 11 of the holding table 10. The Z-axis movement unit 60 moves the holding table 10 and at least the imaging means 26 of the laser light irradiation unit 20 relative to each other in the Z axis direction. In this embodiment, the Z-axis movement unit 60 is installed on a vertical wall 3 that is erected from the main body 2 of the laser light irradiation device 1.

[0039] The Z-axis movement unit 60 supports at least the imaging means 26 of the laser beam irradiation unit 20 so as to be movable in the Z-axis direction. In this embodiment, the Z-axis movement unit 60 includes a well-known ball screw 61, a well-known pulse motor 62, and a well-known guide rail 63. The ball screw 61 is rotatably mounted around its axis. The pulse motor 62 rotates the ball screw 61 around its axis. The guide rail 63 supports the laser beam irradiation unit 20 so as to be movable in the Z-axis direction. The guide rail 63 is fixedly mounted on the vertical wall 3.

[0040] The imaging unit 70 images the plate-shaped object 100 held on the holding surface 11 of the holding table 10. The imaging unit 70 includes a CCD (Charge Coupled Device) camera or an infrared camera for imaging the plate-shaped object 100 held on the holding surface 11. The imaging unit 70 is fixed, for example, adjacent to the imaging means 26 (see Figure 4) of the laser light irradiation unit 20. The imaging unit 70 images the plate-shaped object 100 to obtain an image for performing alignment between the plate-shaped object 100 and the laser light irradiation unit 20, and outputs the obtained image to the control unit 90.

[0041] The display unit 80 is a display unit composed of a liquid crystal display device or the like. The display unit 80 displays, for example, the processing condition setting screen, the status of the plate-shaped object 100 captured by the imaging unit 70, the status of the processing operation, etc., on its display surface. If the display surface of the display unit 80 includes a touch panel, the display unit 80 may also include an input unit. The input unit can accept various operations from the operator, such as registering processing content information. The input unit may also be an external input device such as a keyboard. The information and images displayed on the display surface of the display unit 80 can be switched by operations from the input unit, etc. The display unit 80 may also include a notification device. The notification device emits at least one of sound and light to notify the operator of the laser beam irradiation device 1 of predetermined notification information. The notification device may also be an external notification device such as a speaker or a light-emitting device.

[0042] The control unit 90 controls each of the above-mentioned components of the laser beam irradiation device 1 to cause the laser beam irradiation device 1 to perform processing operations on the plate-shaped object 100. The control unit 90 controls the laser beam irradiation unit 20, the moving unit 30, the imaging unit 70, and the display unit 80. The control unit 90 is a computer that includes an arithmetic processing unit as a calculation means, a storage device as a storage means, and an input / output interface device as a communication means. The arithmetic processing unit includes, for example, a microprocessor such as a CPU (Central Processing Unit). The storage device has memory such as ROM (Read Only Memory) or RAM (Random Access Memory). The arithmetic processing unit performs various calculations based on a predetermined program stored in the storage device. The arithmetic processing unit outputs various control signals to each of the above-mentioned components via the input / output interface device according to the calculation results, thereby controlling the laser beam irradiation device 1. The control unit 90 has a phase pattern storage unit 91 and a phase pattern control unit 92.

[0043] The phase pattern storage unit 91 stores multiple phase patterns. The multiple phase patterns stored in the phase pattern storage unit 91 have different positions on the plane of the plate-shaped object 100 where the laser light 21 is irradiated when displayed on the spatial light modulator 25. Specifically, when each phase pattern is displayed on the spatial light modulator 25, the position where the laser light 21 is irradiated corresponds to the region of each different semiconductor chip 120 mounted on the substrate 110.

[0044] The phase pattern control unit 92 switches the phase pattern displayed on the spatial light modulator 25 to a predetermined phase pattern from among a plurality of phase patterns stored in the phase pattern storage unit 91, so as to change the position in which the laser beam 21 is irradiated within the plane of the plate-shaped object 100. By the phase pattern control unit 92 switching the phase pattern displayed on the spatial light modulator 25, the laser beam 21 is scanned two-dimensionally within the plane of the plate-shaped object 100. More specifically, by the phase pattern control unit 92 switching the phase pattern displayed on the spatial light modulator 25 to a phase pattern that irradiates the area corresponding to each semiconductor chip 120 with the laser beam 21, the laser beam 21 is scanned two-dimensionally within the area corresponding to the semiconductor chip 120 within the plane of the substrate 110, causing the bumps 130 included in the irradiated area of ​​the laser beam 21 to reflow.

[0045] Next, the operation of the laser beam irradiation device 1 irradiating the plate-shaped object 100 of the embodiment, which is held on the holding table 10 with its back surface 112 side, to reflow the bumps 130 will be described. Figure 5 is a perspective view showing the state in which the laser beam 21-1, modulated by the first phase pattern, is imaged onto the plate-shaped object 100. Figure 6 is a perspective view showing the state in which the laser beam 21-2, modulated by the second phase pattern, is imaged onto the plate-shaped object 100. Figure 7 is a perspective view showing the state in which the laser beam 21-3, modulated by the third phase pattern, is imaged onto the plate-shaped object 100. Figure 8 is a perspective view showing the state in which the laser beam 21-4, modulated by the fourth phase pattern, is imaged onto the plate-shaped object 100. Figure 9 is a cross-sectional view of the main part of the plate-shaped object 100 shown in Figures 5 and 6.

[0046] The laser beam irradiation device 1 first displays a first phase pattern on the spatial light modulator 25 of the laser beam irradiation unit 20. The first phase pattern is a phase pattern that modulates the laser beam 21 so that the irradiation area of ​​the modulated laser beam 21-1 shown in Figure 5 corresponds to the region of the semiconductor chip 120-1.

[0047] The laser irradiation device 1 then irradiates the plate-shaped object 100 with laser light 21 from the surface 111 side. As a result, the laser light 21-1 modulated by the first phase pattern is irradiated from the other side (back surface 122) opposite to the side (front surface 121) of the semiconductor chip 120-1 that has the bumps 130. At this time, since the irradiation range of the laser light 21-1 corresponds to the region of the semiconductor chip 120-1, the bumps 130 corresponding to the entire surface of the semiconductor chip 120-1 are reflowed, and the semiconductor chip 120-1 is connected to the substrate 110. For example, the laser irradiation device 1 irradiates one semiconductor chip 120 with laser light 21 for 1 second.

[0048] The laser beam irradiation device 1 then switches the phase pattern displayed on the spatial light modulator 25 of the laser beam irradiation unit 20 from the first phase pattern to the second phase pattern. The time required to switch the phase pattern is, for example, about 30 msec. The second phase pattern is a phase pattern that modulates the laser beam 21 so that the irradiation area of ​​the modulated laser beam 21-2 shown in Figure 6 corresponds to the region of the semiconductor chip 120-2.

[0049] As a result, the irradiation range of the laser beam 21 switches from the region corresponding to semiconductor chip 120-1 to the region corresponding to semiconductor chip 120-2. That is, the laser beam 21-2 modulated by the second phase pattern is irradiated from the other side (back surface 122) opposite to the side (front surface 121) of the semiconductor chip 120-2 that has the bumps 130, causing the bumps 130 corresponding to the entire surface of the semiconductor chip 120-2 to be reflowed and the semiconductor chip 120-2 to be connected to the substrate 110.

[0050] Similarly, the laser beam irradiation device 1 switches the phase pattern displayed on the spatial light modulator 25 of the laser beam irradiation unit 20 from the second phase pattern to the third phase pattern. The third phase pattern is a phase pattern that modulates the laser beam 21 such that the irradiation range of the modulated laser beam 21-3 shown in Figure 7 corresponds to the region of the semiconductor chip 120-3.

[0051] As a result, the irradiation range of the laser beam 21 switches from the region corresponding to semiconductor chip 120-2 to the region corresponding to semiconductor chip 120-3. That is, the laser beam 21-3 modulated by the third phase pattern is irradiated from the other side (back surface 122) opposite to the side (front surface 121) of the semiconductor chip 120-3 that has the bumps 130, causing the bumps 130 corresponding to the entire surface of the semiconductor chip 120-3 to be reflowed and the semiconductor chip 120-3 to be connected to the substrate 110.

[0052] Similarly, the laser beam irradiation device 1 switches the phase pattern displayed on the spatial light modulator 25 of the laser beam irradiation unit 20 from the third phase pattern to the fourth phase pattern. The fourth phase pattern is a phase pattern that modulates the laser beam 21 such that the irradiation range of the modulated laser beam 21-4 shown in Figure 8 corresponds to the region of the semiconductor chip 120-4.

[0053] As a result, the irradiation range of the laser beam 21 switches from the region corresponding to semiconductor chip 120-3 to the region corresponding to semiconductor chip 120-4. That is, the laser beam 21-4 modulated by the fourth phase pattern is irradiated from the other side (back surface 122) opposite to the side (front surface 121) of the semiconductor chip 120-4 that has the bumps 130, causing the bumps 130 corresponding to the entire surface of the semiconductor chip 120-4 to be reflowed and the semiconductor chip 120-4 to be connected to the substrate 110.

[0054] In this way, by switching the phase pattern while the laser beam 21 is irradiated onto the plate-shaped object 100, the irradiation range of the laser beam 21 is sequentially switched within the plane of the plate-shaped object 100. That is, as shown in Figure 9, within the range in which the laser beam 21 can irradiate, the laser beam 21 can be scanned two-dimensionally within the plane of the plate-shaped object 100 by changing the angle at which the laser beam 21 is incident on the plate-shaped object 100 using the phase pattern.

[0055] As described above, the laser beam irradiation device 1 of the embodiment can change the angle at which the laser beam 21 is incident on the plate-shaped object 100 by switching the phase pattern using the spatial light modulator 25, thereby enabling two-dimensional scanning of the irradiation area of ​​the plate-shaped object 100 irradiated by the laser beam 21. Therefore, it is possible to ensure power density and achieve a simple device configuration without the need for a separate scanning means.

[0056] Furthermore, compared to physically moving the holding table 10 and the imaging means that focuses the laser beam 21 onto the plate-shaped object 100, the time required for switching the phase pattern of the spatial light modulator 25 is shorter, thus contributing to improved productivity. The time required to move the holding table 10 is, for example, about 1 second, and the time required for switching the phase pattern is, for example, about 30 msec.

[0057] In other words, for example, as shown in Figures 5 to 8, when irradiating four semiconductor chips 120 with laser light 21, if the semiconductor chips 120 to be irradiated are switched by moving the holding table 10, it takes 4 seconds for movement and 1 second for laser light irradiation, for a total of 8 seconds. In contrast, in this embodiment, it takes 120 msec for switching the phase pattern and 1 second for laser light irradiation, for a total of 4 seconds.

[0058] It should be noted that the present invention is not limited to the embodiments described above. That is, it can be implemented with various modifications without departing from the core principles of the present invention.

[0059] For example, if the irradiation area of ​​the plate-shaped object 100 is larger than the irradiation range of the spatial light modulator 25, the laser is first irradiated into the irradiation range of the spatial light modulator 25 (first irradiation range) by switching the phase pattern at a predetermined position, then the plate-shaped object 100 is moved by the moving unit 30, and the laser is irradiated into the irradiation range of the spatial light modulator 25 (second irradiation range) again by switching the phase pattern. This makes it possible to efficiently irradiate the bump 130 with a laser even if the irradiation area is wide, thereby reflowing the bump 130.

[0060] Furthermore, the configuration is not limited to one phase pattern corresponding to irradiation of one semiconductor chip 120; one phase pattern can also correspond to irradiation of multiple semiconductor chips 120.

[0061] Furthermore, in this embodiment, the imaging means 26 is composed of an imaging system 27, a magnifying imaging lens 28, and a telecentric lens 29, which are provided separately from the spatial light modulator 25, but the imaging function may also be that of the spatial light modulator 25. [Explanation of symbols]

[0062] 1. Laser beam irradiation device 10 Retention Table 20 Laser beam irradiation unit 21 Laser light 22 Laser light source 25. Spatial Light Modulator 26 Image-forming means 30 Mobile Units 70 Imaging Unit 80 Display Units 90 Control Unit 91 Phase pattern storage unit 92 Phase Pattern Control Unit 100 Plate-like objects 110 circuit boards 111 Surface 112 Back side 120 semiconductor chips 121 Surface (one side) 122 Reverse side (the other side) 130 Bump

Claims

1. A holding table for holding plate-shaped objects, A laser beam irradiation unit that irradiates a plate-shaped object held on the holding table with laser light, A laser beam irradiation device comprising a control unit for controlling each component, The laser beam irradiation unit is A laser light source that emits the laser light, A spatial light modulator that modulates and emits laser light emitted from the laser light source according to a phase pattern, An imaging means for imaging the laser light modulated by the spatial light modulator and irradiating it onto a plate-shaped object, Includes, The control unit is, A phase pattern storage unit that stores multiple phase patterns in which the laser light is irradiated at different positions on the surface of the plate-shaped object when displayed on the spatial light modulator, A phase pattern control unit switches the phase pattern to be displayed on the spatial light modulator to a predetermined phase pattern from among a plurality of phase patterns stored in the phase pattern storage unit, It has, The phase pattern control unit switches the phase pattern displayed on the spatial light modulator to switch the irradiation range of the laser beam from a first region on the surface of the plate-like object to a second region that does not include the first region, and by sequentially switching the phase pattern to sequentially switch the irradiation range of the laser beam on the surface of the plate-like object, it is possible to scan the laser beam two-dimensionally on the surface of the plate-like object. Laser light irradiation device.

2. The device is further characterized by comprising a moving unit that moves the holding table and the imaging point of the laser beam relative to each other. The laser light irradiation apparatus according to claim 1.

3. The plate-like object is A substrate on which multiple semiconductor chips, each having bumps on one side, are mounted via these bumps. The multiple phase patterns stored in the phase pattern storage unit include each phase pattern in which the position where the laser light is irradiated when displayed on the spatial light modulator corresponds to the region of each semiconductor chip mounted on the substrate. The phase pattern control unit switches the phase pattern displayed on the spatial light modulator to switch the irradiation range of the laser beam from a region corresponding to a first semiconductor chip to a region corresponding to a second semiconductor chip different from the first semiconductor chip, and by sequentially switching the phase pattern to sequentially switch the irradiation range of the laser beam to the regions corresponding to each of the semiconductor chips, thereby enabling the laser beam to be scanned two-dimensionally within the region corresponding to the semiconductor chip on the surface of the substrate, and the bumps included in the irradiation range of the laser beam to be reflowed. The laser light irradiation device according to claim 1 or 2.

4. The imaging means is characterized by being the imaging function of the spatial light modulator. A laser light irradiation device according to any one of claims 1 to 3.

Images