Laser debonding apparatus

Abstract

Disclosed is a laser debonding apparatus that transmits light energy to a release layer between a carrier substrate of an object to be processed and a device, thereby separating the device from the carrier substrate. The laser debonding apparatus disclosed herein comprises: a light source for generating laser light; a beam shaper for shaping the laser light into a processing beam; and a projection optical system for projecting the processing beam onto the release layer. The laser light is pulsed UV laser light that photochemically decomposes the release layer.

Description

Laser debonding device

[0001] The present disclosure relates to a laser debonding device.

[0002] In a semiconductor process, a device wafer, such as a glass substrate, silicon substrate, or sapphire substrate, is attached to a carrier substrate, and multiple circuit elements are formed on the device wafer through a series of semiconductor processes. The device wafer is supported on the carrier substrate by a release layer and an adhesive layer. After the semiconductor process is completed, the device wafer with multiple circuit elements formed thereon is separated from the carrier substrate. The device wafer and the multiple circuit elements can be collectively referred to as a device. The release layer is interposed between the carrier substrate and the adhesive layer and reduces the adhesive strength of the adhesive layer by absorbing light energy and undergoing thermal decomposition. Consequently, the adhesive strength between the device and the carrier substrate is weakened, allowing the device to be separated from the carrier substrate by moving the carrier substrate relative to the device.

[0003] The present disclosure aims to provide a laser debonding device capable of reducing damage to the device caused by thermal effects during the process of supplying light energy to the release layer of a workpiece.

[0004] The present disclosure aims to provide a laser debonding device capable of stably supplying light energy to the entire area of ​​the release layer of a workpiece.

[0005] The present disclosure aims to provide a laser debonding device capable of stable processing despite warpage of the workpiece.

[0006] A laser debonding device according to one aspect of the present disclosure is a laser debonding device that separates a device from a carrier substrate by transferring light energy to a release layer between a carrier substrate of a workpiece and a device, and comprises: a light source that generates laser light; a beam shaper that shapes the laser light into a processing beam; and a projection optical system that projects the processing beam onto the release layer; wherein the laser light is a UV pulse laser light with a wavelength of 10 to 400 nm that photochemically decomposes the release layer.

[0007] In one embodiment, the beam shaper can shape the laser light so that the processing beam has a flat intensity profile.

[0008] In one embodiment, the beam shaping device can shape the laser light such that the cross-sectional shape of the processing beam, which is orthogonal to the optical axis, becomes a square shape.

[0009] In one embodiment, the processing beam projected onto the molded layer may have a cross-sectional shape orthogonal to the optical axis that is a square shape with a side length of 100 μm or more.

[0010] As one embodiment, the processing beam projected onto the molded layer may have a cross-sectional shape orthogonal to the optical axis and a side length of 500 to 700 μm.

[0011] As one embodiment, the beam quality factor value of the processing beam may be 20 or more.

[0012] In one embodiment, the projection optical system includes a scanner that scans the processing beam in two dimensions, and the laser debonding device may further include a control unit that controls the scanner so that the processing beams partially overlap each other.

[0013] As one embodiment, the overlap amount of the processing beam may be 10% to 60%.

[0014] In one embodiment, the depth of focus of the optical system including the light source, the beam shaper, and the projection optical system may be ±5mm or more.

[0015] In one embodiment, the depth of focus may be set so that the entire area of ​​the release layer is located within the depth of focus, regardless of the magnitude of bending occurring in the device of the workpiece.

[0016] In one embodiment, the projection optical system may include: a field lens for adjusting the divergence angle of the processing beam incident from the beam shaper; and a condensing lens for concentrating the processing beam that has passed through the field lens onto the shape layer of the workpiece.

[0017] In one embodiment, the condensing lens includes an F-theta lens, and the focal length of the F-theta lens may be 250 mm or more.

[0018] As one embodiment, the focal length of the field lens may be 2500mm or more.

[0019] In one embodiment, the projection optical system may include a movable reflective mirror movably disposed between the field lens and the condensing lens to adjust the optical distance between the field lens and the condensing lens.

[0020] In one embodiment, the projection optical system may include an optical mask disposed at the exit side of the condenser lens to reshape the processing beam so that it has a sharp, flat intensity profile.

[0021] As one embodiment, the projection optical system may include a scanner positioned on the incident side of the condensing lens to two-dimensionally scan the processing beam.

[0022] By employing UV laser light as the processing beam, the thermal effect on the device can be reduced, and light energy can be effectively absorbed into the release layer. As a result, the release layer can be photochemically decomposed with high efficiency.

[0023] By employing a processed beam with a flat strength profile, the risk of device damage caused by the accumulation of thermal stress can be reduced.

[0024] By employing a processing beam with a square cross-section orthogonal to the optical axis, light energy can be uniformly provided to the molded layer, and the debonding processing speed can be improved compared to the case where a processing beam with a circular cross-section is employed.

[0025] Uniform debonding is possible by partially overlapping the processing beams.

[0026] By employing an optical system with a depth of focus of ±5mm or more, stable debonding processing is possible despite warpage of the workpiece.

[0027] An optical system having a depth of focus of ±5mm or more can be easily implemented by combining a focal length of 250 or more for an F-theta lens, a focal length of 2500 for a field lens, and a beam quality factor value of 20 or more for a processing beam.

[0028] FIG. 1 is a schematic diagram of a laser debonding device according to one embodiment of the present disclosure.

[0029] FIG. 2 is an exemplary partial cross-sectional view of a workpiece according to one embodiment of the present disclosure.

[0030] FIGS. 3 and FIGS. 4 are drawings showing a debonding process according to an exemplary embodiment.

[0031] Figure 5 is a diagram showing a processing process using laser light according to a comparative example.

[0032] FIG. 6 exemplarily shows a cross-sectional shape perpendicular to the optical axis of a processing beam according to one embodiment of the present disclosure.

[0033] FIG. 7 is an exemplary partial configuration diagram of one embodiment of a low-risk debonding device.

[0034] FIG. 8 is a schematic diagram of one embodiment of a projection optical system.

[0035] FIG. 9 is a schematic diagram of one embodiment of a projection optical system.

[0036] FIG. 10 is a drawing that exemplarily shows the bending of a workpiece.

[0037] Hereinafter, embodiments of a laser debonding device according to the present disclosure will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals refer to the same components, and the size or thickness of each component may be exaggerated for clarity of explanation.

[0038] FIG. 1 is a schematic diagram of a laser debonding device according to one embodiment of the present disclosure. FIG. 2 is an exemplary partial cross-sectional view of a workpiece (1) according to one embodiment of the present disclosure. First, referring to FIG. 1, the laser debonding device may include a light source (200) that generates laser light (L), a beam shaper (300) that shapes the laser light (L) into a processing beam (PL), and a projection optical system (400) that projects the processing beam (PL) onto a release layer (Fig. 2: 12) of the workpiece (1). The laser debonding device may include a control unit (500) that controls the light source (200), the beam shaper (300), and the projection optical system (400).

[0039] The control unit (500) controls the components of the laser debonding device to concentrate a processing beam (PL) at a predetermined location inside the workpiece (1). The control unit (500) may, for example, be equipped with a processor, memory, and input means. A control program for controlling the laser debonding device may be stored in the memory. A processing command including various parameters regarding the location to irradiate the processing beam (PL) may be input through the input means. The processor may control the laser debonding device to irradiate the processing beam (PL) at a desired location by running the control program stored in the memory. The input means may, for example, be a host computer connected to the laser debonding device, or it may be an input means such as a keyboard provided in the laser debonding device itself.

[0040] The workpiece (1) may be supported, for example, on a stage (100). The stage (100) may be moved laterally, for example, in the X direction and / or the Y direction, by means of movement not shown. Additionally, the stage (100) may be moved in the Z direction perpendicular to the X direction and the Y direction. Additionally, the stage (100) may be rotated about the Z direction as an axis.

[0041] Referring to FIG. 2, the workpiece (1) may include a carrier substrate (11) and a device (16) supported on the carrier substrate (11). The device (16) may include a device wafer (14) and a device layer (15) comprising a plurality of circuit elements formed by a series of semiconductor processes on one side, for example, the lower side, of the device wafer (14). The carrier substrate (11) may be, for example, a glass substrate. A release layer (12) may be formed on one side (the lower side in FIG. 2) of the carrier substrate (11). The device wafer (14) may be, for example, a wafer used in semiconductor processes such as a glass substrate, a silicon substrate, or a sapphire substrate. The device wafer (14) may be attached to the lower side of the carrier substrate (11) via the release layer (12). For example, a device (16) may be attached to a carrier substrate (11) by an adhesive layer (13) such that one side (upper side in FIG. 2) faces the lower side of the carrier substrate (11). In this state, a device layer (15) containing a plurality of circuit elements is formed on the other side (lower side in FIG. 2) of the device wafer (14) by a series of semiconductor processes. As another example, after the device layer (15) containing a plurality of circuit elements is formed on the other side (lower side in FIG. 2) of the device wafer (14) by a series of semiconductor processes, the device wafer (14) may be attached to the carrier substrate (11) by an adhesive layer (13) via a release layer (12).

[0042] After the semiconductor process is performed, a debonding process may be performed to separate the device (16) from the carrier substrate (11). FIGS. 3 and 4 are drawings showing a debonding process according to an exemplary embodiment. Referring to FIG. 3, the laser debonding device of the present embodiment weakens the adhesion between the device (16) and the adhesive layer (13) by supplying light energy to the release layer (12) to photodecompose and / or thermally decompose the material forming the release layer (12). Then, as shown in FIG. 4, the device (16) is separated from the carrier substrate (11) by lifting the carrier substrate (11) to the opposite side of the device (16). The release layer (12) is, for example, a material layer that absorbs light energy, converts it into heat energy, and decomposes by this heat energy, so-called LTHC (Light-To-Heat-Conversion) layer.

[0043] Conventionally, a SW-IR (Short wavelength Infrared) laser having a wavelength of 1064 nm was used. Since the SW-IR laser heats the release layer (12) by radiative heating, the radiative energy is easily transferred to the device (16), which can cause thermal damage to the device (16). For example, if a polymer-based material such as a low-k material (low dielectric material) used in the device layer (15) is heated to a temperature of 300°C or higher in an instant, it may melt or deform, causing a malfunction of the circuit element formed in the device layer (15).

[0044] Taking these points into consideration, the light source (200) according to the present disclosure generates laser light (L) in a relatively short wavelength band, for example, UV laser light that photochemically decomposes the release layer (12). For example, the light source (200) can generate UV laser light in a wavelength band of 10 to 400 nm. Since UV laser light is relatively short wavelength light, light energy is photochemically absorbed by the release layer (12). Therefore, UV laser light generates less heat in the irradiated object compared to SW-IR laser, so the thermal effect on the device (16) can be reduced. According to one experimental example, when SW-IR laser is applied, the temperature of the irradiated object is raised to about 300°C, but when UV laser light is applied, the temperature of the irradiated object is about 100°C, so the thermal effect on the irradiated object is significantly reduced. Instead, the photochemical absorption rate of UV laser light is relatively higher than that of SW-IR laser. Therefore, the energy of the UV laser light is effectively absorbed by the release layer (12), so that the release layer (12) can be photochemically decomposed with high efficiency.

[0045] For example, the laser light (L) may be UV pulsed laser light having a wavelength of 355 ± 10 nm. For example, the laser light (L) may be an ultrashort pulsed laser beam having a pulse width of 1 μs or less, for example, on the order of nanoseconds, picoseconds, or femtoseconds. For example, the laser light (L) may be 100 to 1000 mJ / cm² 2 It can have the energy of.

[0046] FIG. 5 is a diagram showing a processing process using laser light according to a comparative example. Referring to FIG. 5, the laser light (L') for delivering light energy to the release layer (12) may have, for example, a Gaussian intensity distribution. The energy of the laser light (L') is concentrated in the central part (Lc') in a cross-section orthogonal to the optical axis of the laser light (L'). Then, a difference in the amount of light energy absorption occurs between the central part (Lc') and the peripheral part (Le') of the laser light (L') in the processing area of ​​the workpiece (1), so the workpiece (1) may not be processed uniformly. In other words, photochemical decomposition may not occur or may occur insufficiently in the area corresponding to the peripheral part (Le') of the laser light (L') in the release layer (12). Additionally, a difference in thermal effect may occur between the central part (Lc') and the peripheral part (Le') of the laser light (L') in the processing area of ​​the workpiece (1), causing thermal stress to accumulate in the workpiece (1). Such non-uniform processing may cause damage to the device (16) when separating the device (16) from the carrier substrate (11). As shown in FIG. 5, the laser light (L') can be scanned onto the workpiece (1) to overlap in two dimensions. However, even in this case, light energy is not sufficiently supplied to the area (AA) between adjacent central parts (Lc') in the processing area of ​​the workpiece (1), so the workpiece (1) may be processed unevenly. Also, as shown in FIG. 5, if the cross-sectional shape orthogonal to the optical axis of the laser light (L') is circular, the amount of overlap of the laser light (L') must be increased to reduce or eliminate the area (AA). This may lead to a decrease in processing speed and energy efficiency.

[0047] FIG. 6 exemplarily shows a cross-sectional shape perpendicular to the optical axis of a processing beam (PL) according to one embodiment of the present disclosure. The laser debonding device of the present disclosure may be equipped with a beam shaper (300) that shapes laser light (L) into a processing beam (PL) having a flat intensity profile. A processing beam (PL) having a flat intensity profile has uniform intensity in the central and peripheral regions in a cross-section perpendicular to the optical axis. It can be considered to have a flat intensity profile if the difference in intensity between the central and peripheral regions is about 10% or less. Therefore, when the processing beam (PL) is irradiated onto a workpiece (1), light energy is evenly provided to the release layer (12) across the entire irradiation area of ​​the processing beam (PL), so that the release layer (12) can be uniformly photochemically decomposed overall. In addition, the thermal effect on the entire area of ​​the workpiece (1) is uniform, so the accumulation of thermal stress can be reduced. Therefore, the risk of damage to the device (16) can be reduced when separating the device (16) from the carrier substrate (11).

[0048] As one embodiment, as illustrated in FIG. 6, the beam shaper (300) can shape the laser light (L) into a processing beam (PL) having a square cross-sectional shape that is orthogonal to the optical axis. For example, the length of one side (PL_e) of the processing beam (PL) projected onto the molding layer (12) by the projection optical system (400) may be 100 μm or more. For example, the processing beam (PL) projected onto the molding layer (12) by the projection optical system (400) may have a square cross-sectional shape with a side length (PL_e) of 100 μm or more. As a non-limiting example, the processing beam (PL) projected onto the molding layer (12) by the projection optical system (400) may have a square cross-sectional shape with a side length (PL_e) of 500 to 700 μm. Taking these points into account, the beam shaper (300) can shape the laser light (L) into a square cross-sectional shape of an appropriate size so that the processing beam (PL) projected onto the molding layer (12) takes into account the magnification of the projection optical system (400) and becomes a square shape with a side length (PL_e) of 500 to 700 μm. With this configuration, compared to the laser beam (L') according to the comparative example having a circular cross-sectional shape, the area (AA) where light energy is provided less or not provided can be reduced or eliminated. In addition, since scanning to eliminate the area (AA) becomes unnecessary, the processing speed can be increased relatively and the processing efficiency can be improved. Furthermore, a laser debonding device effective for processing large-area workpieces (1) can be implemented.

[0049] In one embodiment, referring to FIG. 6, the control unit (500) can control the projection optical system (400) so that the processing beams (PL) are scanned to overlap each other. Even in the case of a processing beam (PL) having a flat intensity profile, the edge portions may have relatively weaker intensity compared to the center portion. Taking this into account, by scanning the processing beams (PL) to overlap each other, light energy can be evenly provided to the entire area of ​​the molding layer (12). When the processing beams (PL) are scanned two-dimensionally, for example, in the X direction and the Y direction, the processing beams (PL) may be scanned to overlap in the X direction and / or the Y direction. The overlap amount (PL_ov) of the processing beams (PL) may be the same for the X direction and the Y direction, or may be different. In this embodiment, the processing beams (PL) have a square cross-sectional shape and have the same overlap amount (PL_ov) in the X direction and the Y direction. For example, if the processing beam (PL) has a square cross-sectional shape, the overlap amount (PL_ov) may be 10% to 60% of the length of one side (PL_ov) of the processing beam (PL). If the overlap amount (PL_ov) is less than 10%, it is not effective in terms of uniformizing the light energy provided to the molding layer (12), and if the overlap amount (PL_ov) is greater than 60%, the number of scans increases, so the processing speed and energy efficiency may be excessively reduced. Therefore, the overlap amount (PL_ov) can be determined by taking into account the intensity profile of the processing beam (PL), the processing speed, and the characteristics of the workpiece (1).

[0050] FIG. 7 is an exemplary partial configuration diagram of one embodiment of a laser debonding device. Referring to FIG. 7, laser light (L) generated from a light source (200) can be converted into parallel light having a Gaussian intensity profile by a collimator (210). If necessary, a beam expander (220) may be placed between the collimator (210) and the beam shaper (300). The beam expander (220) converts the beam diameter of the laser light (L). The beam expander (220) may include two or more lenses and can convert the beam diameter of the laser light (L) by adjusting the distance between the lenses. For example, the beam expander (220) may include a first lens having a negative refractive power and a second lens having a positive refractive power, and the beam diameter of the laser light (L) can be adjusted according to the distance between the first lens and the second lens. The beam diameter adjuster (220) may further be equipped with a third lens, and the third lens may convert the laser light (L) that has passed through the first and second lenses into parallel light. In this regard, the beam diameter adjuster (220) may be implemented by one or more collimators. For example, the beam diameter adjuster (220) may magnify the diameter of the laser light (L) by about three times or more.

[0051] Accordingly, collimated laser light (L) having a Gaussian intensity profile can be provided to the beam shaper (300). The beam shaper (300) shapes the laser light (L) into a processed beam (PL) having a square cross-sectional shape with a flat intensity profile. The optical configuration of the beam shaper (300) may vary. For example, the beam shaper (300) may include a lens array, an aspherical lens pair, a waveguide optical system, a Powell lens module, and a diffraction optical element (DOE). For example, the lens array has a structure in which a plurality of micro-lenses are arranged in an array form, and each micro-lens diffuses light and overlaps it to equalize the light intensity distribution. For example, the waveguide optical system equalizes the light intensity distribution by passing light through the interior of a glass rod, etc., so that it is repeatedly reflected. For example, a line beam can be formed by a single Powell lens, and a square beam with a flat intensity profile can be formed by two Powell lenses.

[0052] Accordingly, a processing beam (PL) having a flat strength profile and a square cross-sectional shape can be provided to a projection optical system (400). The projection optical system (400) projects the processing beam (PL) onto a molding layer (12) of a workpiece (1). The projection optical system (400) focuses the processing beam (PL) onto the molding layer (12) of the workpiece (1).

[0053] The device layer (15) on the device (16) is formed by stacking various material layers. When various material layers with different coefficients of thermal expansion are stacked, warpage may occur in the device (16) during the debonding process. This warpage persists even when the device (16) is bonded to the carrier substrate (11). FIG. 10 is a drawing that exemplarily shows the warpage of the workpiece (1). In FIG. 10, reference numeral 18 refers collectively to the device (16), the bonding layer (13), and the release layer (12). Such warpage of the workpiece (1) causes the optical distance between the release layer (12) and the projection optical system (400) to be non-uniform, which affects the uniformity of light energy transfer from the processing beam (PL) to the release layer (12), and thus the release layer (12) may not be processed uniformly. In a general semiconductor process, the warpage (WPG) is approximately ±2 to 3 mm. If the depth of focus of the processing beam (PL) is smaller than the bending (WPG), processing defects may occur in the area beyond the depth of focus range.

[0054] In light of these points, the laser debonding device according to the present disclosure is configured such that the entire optical system, including the projection optical system (400), has a long depth of focus (long DOF). When the processing beam (PL) is irradiated onto the workpiece (1), it can effectively transmit light energy to the workpiece (1), for example, the release layer (12), in the region corresponding to the depth of focus. The degree of warping of the workpiece (1) may be influenced by the number of material layers forming the device (16), the coefficient of thermal expansion of each material layer, and the size of the device wafer (14). Accordingly, the depth of focus of the optical system of the laser debonding device can be determined by taking into account the degree of warping of the workpiece (1) due to these factors. For example, the optical system of the laser debonding device according to the present disclosure has a depth of focus of ±5 mm or more. The focal depth of the processing beam (PL) can be set by various optical elements described below so that the entire area of ​​the release layer (12) is located within the focal depth of the processing beam (PL), regardless of the magnitude of the bending occurring in the device (16) of the workpiece (1). As described above, in a general semiconductor process, the bending of the workpiece (1) is about ±2 to 3 mm; therefore, if the optical system of the laser debonding device has a focal depth of ±5 mm or more, it can stably and uniformly provide light energy to the workpiece (1) despite the bending of the workpiece (1).

[0055] Furthermore, the depth of focus is the beam quality factor (M) of the processing beam (PL). 2 It is proportional to the beam quality factor. The beam quality factor of a laser beam having a Gaussian intensity profile is "1". According to the present disclosure, the processing beam (PL) has a flat intensity profile, and the beam quality factor is greater than 1. Therefore, according to the present disclosure, it is possible to easily implement a laser debonding device having an optical system having a long depth of focus. For example, the processing beam (PL) may have a beam quality factor of 20 or more.

[0056] FIG. 8 is a schematic diagram of one embodiment of a projection optical system (400). Referring to FIG. 8, the projection optical system (400) may include a condensing lens (410) that concentrates a processing beam (PL) onto a molding layer (12). The projection optical system (400) of this embodiment further comprises a scanner (420). The scanner (420) may be positioned on the incident side of the condensing lens (410) and may further comprise a scanner (420) that scans the processing beam (PL) in two dimensions. The scanner (420) may be a two-axis scanner that scans the processing beam (PL) in, for example, X and Y directions. For example, the scanner (420) may include a first scanner that scans the processing beam (PL) in a first direction (e.g., X direction) and a second scanner that scans the processing beam (PL) scanned in the first direction by the first scanner in a second direction (e.g., Y direction) orthogonal to the first direction. Each of the first and second scanners may include, for example, a reflective mirror and a scanner motor that drives the reflective mirror to rotate.

[0057] The control unit (500) controls the scanner motors of the scanner (420), for example, the first and second scanners, to scan the processing beam (PL) in the first direction and the second direction. Additionally, as described in FIG. 6, the control unit (500) controls the scanner motors of the scanner (420), for example, the first and second scanners, so that the processing beam (PL) overlaps with an adjacent processing beam (PL) on the workpiece (1) by a predetermined overlap amount (PL_ov) determined within the range of 10% to 60%.

[0058] The focusing lens (410) focuses the processing beam (PL) that has passed through the scanner (420) onto the molding layer (12). The focusing lens (410) may include one or more lenses. The processing beam (PL) is scanned in two dimensions by the scanner (420). The focusing lens (410) needs to focus the two-dimensionally scanned processing beam (PL) onto a flat focal plane. Taking this into account, the focusing lens (410) may include an F-theta lens (411). Accordingly, the two-dimensionally scanned processing beam (PL) can be focused by the F-theta lens (411) onto a flat molding layer (12) that is positioned at a predetermined optical distance in the direction of the optical axis from the projection optical system (400).

[0059] The depth of focus of the optical system of the laser debonding device is proportional to the focal length of the F-theta lens (411). The focal length of the F-theta lens (411) may be 250 mm or more. Accordingly, a laser debonding device having an optical system with a depth of focus of ±5 mm or more can be easily implemented.

[0060] The depth of focus of the optical system of the laser debonding device is affected by the divergence angle of the processing beam (PL) incident on the condensing lens (410). For example, the depth of focus of the optical system of the laser debonding device increases as the divergence angle of the processing beam (PL) incident on the condensing lens (410) decreases. Referring to FIG. 8, the projection optical system (400) may further be equipped with a field lens (430) that controls the divergence angle of the processing beam (PL). The field lens (430) may be positioned at the front end of the scanner (420). The condensing lens (410) controls the divergence angle of the processing beam (PL), which is two-dimensionally scanned by the scanner (420), and focuses it onto the release layer (12) of the workpiece (1). For example, the field lens (430) may have a positive refractive power. The magnification of the projection optical system (400) is determined by the focal length of the field lens (430) and the focal length of the f-theta lens (411). For example, if the focal length of the field lens (430) is f1 and the focal length of the f-theta lens (411) is f2, the magnification of the projection optical system (400) is f2 / f1. The focal length f1 of the field lens (430) can be determined by taking into account the desired magnification of the projection optical system (400). For example, the magnification of the projection optical system (400) can be 10, in which case the focal length of the field lens (430) can be 2500 mm or more. By doing so, an optical system having a depth of focus of ±5 mm or more can be easily implemented. The beam shaper (300) can adjust the size of the cross-section of the processing beam incident on the projection optical system (400) so that the processing beam (PL) focused on the workpiece (1) takes into account the magnification of the projection optical system (400) and becomes a square-shaped beam with a side length of, for example, 500 to 700 μm.Conventionally, a combination of an F-theta lens / field lens having a focal length of 10 mm / 100 mm was used, but in the laser debonding device of the present disclosure, by adopting a combination of an F-theta lens (411) / field lens (430) having a focal length of 250 mm or more / 2500 mm or more, it is possible to implement an optical system having a long focal length of ±5 mm or more, and thereby, high-quality laser debonding processing is possible despite the bending of the workpiece (1).

[0061] As an example of one embodiment, as shown in FIG. 8, a condenser lens (440) may be placed in the front section of the projection optical system (400), for example, between the beam shaper (300) and the field lens (430). The condenser lens (440) shapes the processing beam (PL) into a desired square beam by adjusting the divergence angle of the processing beam (PL) emitted from the beam shaper (300). The condenser lens (440) can adjust the processing beam (PL) emitted from the beam shaper (300) into a convergent beam. For example, the condenser lens (440) can adjust the divergence angle of the processing beam (PL) incident on the projection optical system (400) so that the processing beam (PL) focused on the workpiece (1) becomes a square-shaped beam with a side length of, for example, 500 to 700 μm, taking into account the magnification of the projection optical system (400). Since the magnification of the optical system is fixed by the combination of the condenser lens (440) and the field lens (430), the distance between the lenses constituting the optical system can be flexibly adjusted.

[0062] FIG. 9 is a schematic diagram of one embodiment of a projection optical system (400a). The projection optical system (400a) of this embodiment differs from the projection optical system (400) shown in FIG. 8 in that it employs an optical mask (450) and a movable reflective mirror (460) for adjusting the optical distance between the field lens (430) and the condensing lens (410). In the following, components having the same function are indicated by the same reference numerals, redundant descriptions are omitted, and the differences are described in detail.

[0063] Referring to FIG. 9, the projection optical system (400a) comprises a condensing lens (410), a scanner (420), and a field lens (430). The same applies to the condensing lens (410), the scanner (420), and the field lens (430) as described in FIG. 8. The projection optical system (400a) may include an optical mask (450). The optical mask (450) may be positioned at the exit side of the field lens (430). The optical mask (450) reshapes the cross-sectional shape orthogonal to the optical axis of the processing beam (PL) passing through the field lens (430) so that the processing beam (PL) has a sharp, flat intensity profile. For example, the optical mask (450) may have a square aperture, and as the processing beam (PL) passes through the square aperture, the cross-sectional shape of the processing beam (PL) may be reshaped into a square cross-sectional shape. A plurality of reflective mirrors (461–467) may be placed in the optical path between the field lens (430) and the condensing lens (410). For example, a plurality of reflective mirrors (461–467) may be placed in the optical path between the optical mask (450) and the scanner (420). The length of the optical path between the field lens (430) and the condensing lens (410) can be adjusted by moving at least two of the plurality of reflective mirrors (461–467). For example, reflective mirrors (463, 464) may be mounted on a moving block (469). The moving block (469) and the reflective mirrors (463, 464) form a movable reflective mirror (460). The moving block (469) may be supported on a shaft extended in the direction of movement. The moving block (469) may be moved in the direction of arrow A1 or A2 in FIG. 9. When the movable reflective mirror (460) is moved from the position shown by the solid line in FIG. 9 to the position shown by the dotted line, the optical distance between the field lens (430) and the condensing lens (410) is reduced.Conversely, if the movable reflective mirror (460) is moved from the position shown by the dotted line in FIG. 9 to the position shown by the solid line, the optical distance between the field lens (430) and the condensing lens (410) increases. Once the divergence angle of the processing beam (PL) is determined by the field lens (430), the beam diameter of the processing beam (PL) incident on the condensing lens (410) changes according to the optical distance. The optical distance between the field lens (430) and the condensing lens (410) can be adjusted by moving the movable reflective mirror (460) so that the projection optical system (400a) has the desired focal size and depth of focus.

[0064] Accordingly, the optical distance between the field lens (430) and the focusing lens (410) can be appropriately adjusted so that the processing beam (PL) concentrated on the workpiece (1) takes into account the beam diameter of the processing beam (PL) incident from the beam shaper (300) and the magnification of the projection optical system (400a), so that the processing beam (PL) concentrated on the workpiece (1) becomes a square-shaped beam with a side length of, for example, 500 to 700 μm.

[0065] Although embodiments of the present invention have been described above, they are merely illustrative and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom.

Claims

1. A laser debonding device that separates a device from a carrier substrate by transferring light energy to a release layer between a carrier substrate of a workpiece and a device, the device being processed A light source that generates laser light; A beam shaper that shapes the above laser light into a processing beam; A projection optical system that projects the above processing beam onto the above-mentioned molded layer; comprising, A laser debonding device in which the above laser light is a UV pulse laser light with a wavelength of 10 to 400 nm that photochemically decomposes the above release layer.

2. In Paragraph 1, The beam shaper above is a laser debonding device that shapes the laser light so that the processing beam has a flat intensity profile.

3. In Paragraph 1, The beam shaping device above is a laser debonding device that shapes the laser light so that the cross-sectional shape of the processing beam, which is orthogonal to the optical axis, becomes a square shape.

4. In Paragraph 3, A laser debonding device in which the processing beam projected onto the above-mentioned release layer has a cross-sectional shape orthogonal to the optical axis and is a square shape with a side length of 100 μm or more.

5. In Paragraph 3, A laser debonding device in which the processing beam projected onto the above-mentioned release layer has a cross-sectional shape orthogonal to the optical axis and is a square shape with a side length of 500 to 700 μm.

6. In Paragraph 1, A laser debonding device in which the beam quality factor value of the above-mentioned processing beam is 20 or higher.

7. In Paragraph 1, The projection optical system includes a scanner that scans the processing beam in two dimensions, and A laser debonding device further comprising: a control unit that controls the scanner so that the processing beams partially overlap each other.

8. In Paragraph 7, A laser debonding device in which the overlap amount of the processing beam is 10% to 60%.

9. In Paragraph 1, A laser debonding device comprising the light source, the beam shaper, and the projection optical system, wherein the depth of focus of the optical system is ±5 mm or more.

10. In Paragraph 9, A laser debonding device in which the above-mentioned depth of focus is set so that the entire area of ​​the release layer is located within the depth of focus, regardless of the magnitude of bending occurring in the device of the workpiece.

11. In Paragraph 9, The above projection optical system is, A field lens for adjusting the divergence angle of the processing beam incident from the beam shaper; A laser debonding device comprising: a focusing lens that focuses the processing beam passing through the field lens onto the release layer of the processing object.

12. In Paragraph 11, The above-mentioned condensing lens includes an F-theta lens, and A laser debonding device having a focal length of 250 mm or more of the above F-theta lens.

13. In Paragraph 11, A laser debonding device having a focal length of 2500mm or more of the field lens.

14. In Paragraph 11, The above projection optical system is, A laser debonding device comprising: a movable reflective mirror movably disposed between the field lens and the condensing lens to adjust the optical distance between the field lens and the condensing lens.

15. In Paragraph 14, A laser debonding device comprising: an optical mask disposed at the exit side of the field lens to reshape the processing beam so that it has a sharp, flat intensity profile.

16. In Paragraph 11, The above projection optical system is, A laser debonding device comprising: a scanner positioned on the incident side of the condensing lens to two-dimensionally scan the processing beam.

Images