Methods for processing substrates

Abstract

This invention relates to a method for processing a substrate having a device region with a plurality of devices on one side. The method includes providing a first protective film; providing a second protective film; attaching the first protective film to one side of the substrate such that at least a central region of the front surface of the first protective film is in direct contact with one side of the substrate; and attaching the second protective film to a side of the substrate opposite to one side. After attaching the second protective film to the side of the substrate opposite to one side, a laser beam is applied to the substrate from the side of the substrate opposite to one side. The substrate is made of a material transparent to the laser beam. The second protective film is also made of a material transparent to the laser beam. The laser beam is applied to the substrate at multiple locations to form a plurality of modified regions in the substrate.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to German patent application No. 10 2020 210104.3, filed with the German Patent and Trademark Office on August 10, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a method for processing a substrate (e.g., a wafer such as a semiconductor wafer) having a device region on one side with a plurality of devices. Background Technology

[0004] In device manufacturing processes (e.g., semiconductor device manufacturing processes), a substrate (e.g., a wafer) having device regions with multiple devices (typically separated by multiple cleaving lines) is diced into individual dies. Device manufacturing processes typically include, for example, dicing the substrate along cleaving lines to obtain individual dies. Furthermore, additional processing steps (such as grinding and / or polishing and / or etching) can be performed on the back side of the substrate, opposite to the front side where the device regions are formed, on which the device regions are formed.

[0005] The substrate can be cut, for example, along a dividing line from the front or back of the substrate. Specifically, the substrate can be cut mechanically, such as by dicing or sawing, by plasma cutting, or by laser cutting. Laser cutting can be performed, for example, by ablation laser cutting and / or by stealth laser cutting, i.e., by applying a laser beam to form modified regions within the substrate, and / or by applying a laser beam to form multiple hole regions in the substrate.

[0006] When conventional mechanical cutting or laser cutting (especially stealth laser cutting) is performed from the front side of a substrate, problems may arise where debris generated during the cutting process damages or contaminates the devices formed in the device area. This problem is particularly pronounced if the substrate includes fragile and / or sensitive structures (e.g., in the device area) and / or metallic structures (e.g., within the dividing line) on the front side of the substrate.

[0007] In particular, a common problem is that the laser beam intended for stealth laser cutting cannot penetrate the metal structure formed on the dicing line, making stealth slicing from the front of the substrate difficult to achieve. Therefore, the laser beam must be applied to the substrate from the rear, as will be detailed below.

[0008] To protect devices formed in the device area from damage and contamination by such debris, a protective film or sheet can be applied to the front side of the substrate before processing, and mechanical or laser cutting, particularly stealth laser cutting, can be performed from the rear side of the substrate. Specifically, when processing the substrate from the rear side in this manner, the substrate is typically placed on a support (e.g., a chuck stage), utilizing the front side of the substrate to contact the support. The protective film or sheet applied to the front side of the substrate protects the device from damage due to contact with the support, such as mechanical damage. However, in this case, a problem exists that the device structure on the substrate may be damaged by the adhesive force of the adhesive layer formed on the protective film or sheet, or may be contaminated by adhesive residues on the device when the film or sheet is peeled off from the substrate. This is particularly relevant if there are fragile and / or sensitive structures on the front side of the substrate, such as sensitive devices like microelectromechanical systems (MEMS). For example, when the protective film or sheet is peeled off from the substrate, the MEMS film may be damaged, for example, cracked.

[0009] To reduce the risk of damage and contamination to the device formed in the device area by the adhesive layer, it has been proposed to apply the adhesive layer only to the outer peripheral portion of the protective film or sheet. However, in this case, the substrate may be difficult to hold reliably during processing because the protective film or sheet may not provide sufficient support for the substrate in the central portion of the film or sheet, which is surrounded by the outer peripheral portion. This problem is exacerbated when there are fragile and / or sensitive structures on the front side of the substrate. For example, if the front side of the substrate includes, for example, a MEMS with a thin film or cavity, pressure and / or heat cannot be applied to the protective film or sheet during and / or after attaching it to the substrate due to the risk of damaging these fragile structures.

[0010] Furthermore, substrate warping can occur when cutting substrates using stealth laser cutting. Specifically, when modified regions are formed within the substrate by applying a laser beam, the substrate volume may increase in these regions, leading to stress and consequently, bending or warping. This is particularly problematic when numerous modified regions are formed within the substrate, such as when stealth laser cutting a substrate with multiple small devices formed on its front side. If the protective film or sheet used has an adhesive layer applied only to its outer periphery, the substrate may not be adequately supported by the film or sheet to prevent warping. Substrate warping can affect the accuracy of the modified regions formed within the substrate, making it difficult to cleave the substrate into individual wafers. For example, during substrate cleaving, some wafers may not be properly separated from each other and / or may be damaged. This problem is especially pronounced when the wafer size is small.

[0011] Therefore, there is still a need for a reliable and efficient method for processing substrates with device areas that allows for minimizing any risk of substrate contamination and damage. Summary of the Invention

[0012] Therefore, the object of the present invention is to provide a reliable and efficient method for processing a substrate having device regions, which allows for minimizing any risk of substrate contamination and damage. This object is achieved by a substrate processing method having the technical features of one aspect of the invention. Preferred embodiments of the invention are derived from another aspect of the invention.

[0013] This invention provides a method for processing a substrate having a device region with a plurality of devices on one side. The method includes: providing a first protective film or protective sheet; providing a second protective film or protective sheet; attaching the first protective film or protective sheet to one side of the substrate such that at least a central region of the front surface of the first protective film or protective sheet is in direct contact with one side of the substrate; and attaching the second protective film or protective sheet to a side of the substrate opposite to one side. After attaching the second protective film or protective sheet to the side of the substrate opposite to one side, a laser beam is applied to the substrate from the side opposite to one side. The substrate is made of a material transparent to the laser beam. The second protective film or protective sheet is also made of a material transparent to the laser beam. The laser beam is applied to the substrate at multiple locations to form a plurality of modified regions in the substrate.

[0014] A first protective film for covering the device formed in the device region is attached to one side of the substrate (i.e., to the front side of the substrate) such that at least the central region of the front surface of the first protective film is in direct contact with one side of the substrate. Therefore, there is no material (especially no adhesive) between at least the central region of the front surface of the first protective film and one side of the substrate.

[0015] Therefore, the risk of contamination or damage to the substrate, such as due to the adhesive force of the adhesive layer or adhesive residue on the substrate, can be significantly reduced or even eliminated.

[0016] A second protective film is attached to the side of the substrate opposite to one side (i.e., to the rear side of the substrate). The second protective film is made of a material transparent to the laser beam. Therefore, the laser beam has a wavelength that allows the laser beam to pass through the second protective film. Thus, after attaching the second protective film to the rear side of the substrate, multiple modified regions can be formed in the substrate by applying the laser beam from the rear side of the substrate through the second protective film to the substrate. During the application of the laser beam to the substrate, the substrate can be reliably supported by the second protective film attached to the substrate. Therefore, any warping of the substrate during processing can be suppressed or even completely avoided, allowing for a significant improvement in the precision of the modified regions that can be formed within the substrate. For example, the modified regions can be uniformly formed at the same depth within the substrate, i.e., at the same location along the thickness direction of the substrate. The thickness direction of the substrate extends from the front side of the substrate toward the rear side of the substrate. Therefore, the substrate can be processed in a particularly efficient manner. In particular, the precise formation of modified regions within the substrate allows the substrate to be reliably divided into individual dies, which is also applicable to cases with small die sizes.

[0017] Therefore, the method of the present invention can reliably and effectively process substrates with device regions, minimizing any risk of contamination and damage to the substrate (especially devices formed in the device regions).

[0018] The substrate can be made of, for example, semiconductors, glass, sapphire (Al2O3), ceramics (such as alumina ceramics), quartz, zirconium oxide, PZT (lead zirconate titanate), polycarbonate, metals (such as copper, iron, stainless steel, aluminum, etc.) or metallized materials, ferrites, optical crystal materials, resins, etc.

[0019] Specifically, the substrate can be made of, for example, silicon carbide (SiC), silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), gallium phosphide (GaP), indium arsenide (InAs), indium phosphide (InP), silicon nitride (SiN), lithium tantalate (LT), lithium niobate (LN), aluminum nitride (AlN), silicon oxide (SiO2), etc.

[0020] The substrate can be a single-crystal substrate, a glass substrate, a composite substrate (such as a composite semiconductor substrate), or a polycrystalline substrate (such as a ceramic substrate).

[0021] The substrate can be a wafer, especially a semiconductor wafer. For example, the substrate can be a silicon carbide (SiC) wafer, a silicon (Si) wafer, a gallium arsenide (GaAs) wafer, a gallium nitride (GaN) wafer, a gallium phosphide (GaP) wafer, an indium arsenide (InAs) wafer, an indium phosphide (InP) wafer, a silicon nitride (SiN) wafer, a lithium tantalate (LT) wafer, a lithium niobate (LN) wafer, an aluminum nitride (AlN) wafer, a silicon oxide (SiO2) wafer, etc.

[0022] The substrate can be made of a single material or a combination of different materials (e.g., two or more of the materials mentioned above). For example, the substrate can be a substrate bonded to Si and glass (e.g., a Si and glass bonded wafer), wherein substrate elements made of Si are bonded to substrate elements made of glass.

[0023] The substrate can have any type of shape. In its top view, the substrate can have, for example, a circular shape, an oval shape, an elliptical shape, or a polygonal shape (such as a rectangular shape or a square shape).

[0024] The devices in the device region on one side of the substrate can be, for example, semiconductor devices, power devices, optical devices, medical devices, electronic components, MEMS devices, or combinations thereof. The device may include, for example, a transistor (such as a MOSFET or an insulated-gate bipolar transistor (IGBT)) or a diode (e.g., a Schottky barrier diode).

[0025] The substrate may also have an outer peripheral edge region on one side that is free of devices and forms around the device area.

[0026] The first protective film can be made of a single material, particularly a single homogeneous material. The first protective film can be a solid sheet. For example, the first protective film can be a foil or a sheet.

[0027] The first protective film can be made of a plastic material (e.g., a polymer). Particularly preferred is that the first protective film is made of a polyolefin. For example, the first protective film can be made of polyethylene (PE), polypropylene (PP), or polybutene (PB).

[0028] Polyolefin films possess material properties particularly advantageous for use in the substrate processing method of the present invention, especially when an external stimulus comprising or consisting of heating the first protective film is applied to it, as will be described in detail below. The polyolefin film is flexible, extensible, and soft when heated (e.g., when heated to a temperature range of 60°C to 150°C). Furthermore, the polyolefin film hardens and stiffens upon cooling, thus becoming more rigid and robust in the cooled state. Therefore, particularly reliable protection of the substrate can be ensured during subsequent substrate processing.

[0029] The first protective film may have a thickness in the range of 5 to 500 μm, preferably 5 to 200 μm, more preferably 8 to 100 μm, even more preferably 10 to 80 μm, and even more preferably 12 to 50 μm. Particularly preferably, the first protective film has a thickness in the range of 80 to 150 μm.

[0030] The first protective film can have any type of shape. In its top view, the first protective film can have, for example, a circular shape, an oval shape, an elliptical shape, or a polygonal shape (such as a rectangular shape or a square shape).

[0031] The first protective film may have a shape substantially the same as or the same as that of the substrate.

[0032] The first protective film may have an outer diameter larger than that of the substrate. In this way, it facilitates the handling, manipulation, and / or transportation of the substrate. In particular, the outer peripheral portion of the first protective film may be attached to an annular frame, as will be detailed below.

[0033] The first protective film can have an outer diameter smaller than that of the substrate.

[0034] The first protective film may have an outer diameter that is substantially the same as that of the substrate.

[0035] The first protective film may have an outer diameter substantially the same as the outer diameter of the device region formed on one side of the substrate.

[0036] The second protective film can be made of a single material, particularly a single homogeneous material. The second protective film can be a solid sheet. For example, the second protective film can be a foil or a sheet.

[0037] The second protective film can be made of a plastic material (e.g., a polymer). Particularly preferred is that the second protective film is made of a polyolefin. For example, the second protective film can be made of polyethylene (PE), polypropylene (PP), or polybutene (PB).

[0038] If an external stimulus, including or consisting of heating the second protective film, is applied to the second protective film, it is particularly advantageous to use a second protective film made of polyolefin, as will be described in detail below.

[0039] The second protective film may have a thickness in the range of 5 to 500 μm, preferably 5 to 200 μm, more preferably 8 to 100 μm, even more preferably 10 to 80 μm, and even more preferably 12 to 50 μm. Particularly preferably, the second protective film has a thickness in the range of 80 to 150 μm.

[0040] The second protective film can have any type of shape. In its top view, the second protective film can have, for example, a circular shape, an oval shape, an elliptical shape, or a polygonal shape (such as a rectangular shape or a square shape).

[0041] The second protective film may have a shape substantially the same as or the same as the substrate. The second protective film may have a shape substantially the same as or the same as the first protective film.

[0042] The second protective film can have an outer diameter larger than that of the substrate. This facilitates the handling, manipulation, and / or transport of the substrate. Specifically, the outer periphery of the second protective film can be attached to an annular frame, as will be described in detail below.

[0043] The second protective film can have an outer diameter smaller than that of the substrate.

[0044] The second protective film can have an outer diameter that is substantially the same as that of the substrate.

[0045] The second protective film may have an outer diameter substantially the same as the outer diameter of the device region formed on one side of the substrate.

[0046] The second protective film may have an outer diameter that is substantially the same as that of the first protective film.

[0047] The laser beam applied to the substrate from the rear side can be a pulsed laser beam. The pulsed laser beam can have a pulse width, for example, in the range of 1 fs to 2000 ns.

[0048] The substrate is made of a material that is transparent to laser beams (e.g., pulsed laser beams). Therefore, multiple modified regions are formed in the substrate by applying a laser beam with a wavelength that allows the laser beam to pass through the substrate. For example, if the substrate is a Si substrate (e.g., a Si wafer), the laser beam can have a wavelength of 1.0 μm or longer.

[0049] When the focal point of the laser beam is located at a certain distance from the opposite side of the substrate, in a direction opposite to one side of the substrate and toward that side, the laser beam (e.g., a pulsed laser beam) can be applied to the substrate at multiple locations to form multiple modified regions in the substrate. Alternatively, when the focal point of the laser beam is located at a certain distance from the opposite side of the substrate, in a direction opposite to the direction opposite to one side of the substrate and toward that side, the laser beam can be applied to the substrate at multiple locations to form multiple modified regions in the substrate. When the focal point of the laser beam is located on the opposite side of the substrate, the laser beam can be applied to the substrate at multiple locations to form multiple modified regions in the substrate. When the focal point of the laser beam is located within the bulk of the substrate, the laser beam can be applied to the substrate at multiple locations to form multiple modified regions in the substrate.

[0050] The modified region is a substrate region that has been modified by the application of a laser beam. The modified region can be a substrate region where the structure of the substrate material has been modified. The modified region can also be a substrate region where the substrate has been damaged.

[0051] By forming these modified regions, the strength of the substrate is reduced in the substrate region where the modified regions are formed. Therefore, it is very convenient to cleave the substrate along the substrate region where multiple modified regions have been formed. In such a substrate cleaving process, individual devices provided in the device region of the substrate are obtained for use as chips or dies.

[0052] The modified region may include an amorphous region and / or a region in which cracks are formed. In a particularly preferred embodiment, the modified region includes or is an amorphous region.

[0053] Each modified region may include a space (e.g., a cavity) within the substrate material, surrounded by amorphous regions and / or regions in which cracks are formed.

[0054] Each modified region may consist of an amorphous region surrounding a space (e.g., a cavity) within the substrate material and / or a region in which cracks are formed.

[0055] If the modified region includes or is a region in which cracks are formed (i.e., cracks have already formed), then the cracks can be microcracks. Cracks can have dimensions in the μm range, such as length and / or width. For example, a crack can have a width in the range of 5 μm to 100 μm and / or a length in the range of 100 μm to 1000 μm.

[0056] In the method of the present invention, attaching the first protective film to one side of the substrate may include applying the first protective film to one side of the substrate such that at least a central region of the front surface of the first protective film is in direct contact with one side of the substrate. Therefore, there is no material (particularly no adhesive) between at least a central region of the front surface of the first protective film and one side of the substrate. Furthermore, attaching the first protective film to one side of the substrate may include applying an external stimulus to the first protective film during and / or after applying the first protective film to one side of the substrate, causing the first protective film to be attached to one side of the substrate. Therefore, the application of the external stimulus generates an adhesion force between the first protective film and the substrate, holding the first protective film in its position on the substrate. Therefore, no additional adhesive material is required to attach the first protective film to one side of the substrate.

[0057] Specifically, by applying external stimulation to the first protective film, a shape fit (e.g., positive fit) and / or material bond (e.g., adhesive bond) can be formed between the first protective film and the substrate. The terms "material bond" and "adhesive bond" define the attachment or connection between the first protective film and the substrate due to atomic and / or molecular forces acting between the two components.

[0058] The term "adhesive bonding" refers to the presence of these atomic and / or molecular forces acting to attach or adhere the first protective film to the substrate, and does not imply the presence of an additional adhesive between the first protective film and the substrate. Rather, as described in detail above, at least the central region of the front surface of the first protective film is in direct contact with one side of the substrate.

[0059] The front surface of the substrate can be a generally flat, smooth surface. Alternatively, the front surface of the substrate may have protrusions or bumps extending from the planar substrate surface along the thickness direction of the substrate and / or recesses (such as trenches, grooves, cuts, etc.) extending inward from the planar substrate surface. The first protective film may be attached to one side of the substrate so as to at least partially follow the contour or morphology of one side of the substrate (e.g., the contour of protrusions or bumps, and / or recesses present on such a substrate side).

[0060] The first protective membrane can be expandable.

[0061] When the first protective film is applied to one side of the substrate, the first protective film can be expanded. Specifically, when the first protective film is applied to one side of the substrate, the first protective film can be expanded so that it at least partially conforms to the contour or shape of one side of the substrate (e.g., the contour of protrusions or bulges and / or recesses present on such a substrate side).

[0062] For example, the first protective film can be expanded to more than twice its original size, preferably more than three times its original size, and more preferably more than four times its original size. In this way, especially for the case of expansion to more than three or four times its original size, it can be reliably ensured that the first protective film conforms to the contour or morphology of one side of the substrate.

[0063] If the first protective film is expandable, it can be used to separate the devices from each other, as will be described in detail below.

[0064] Applying external stimulation to the first protective film may include or consist of the following: applying pressure to the first protective film, and / or heating the first protective film, and / or cooling the first protective film, and / or applying a vacuum to the first protective film, and / or irradiating the first protective film with radiation (such as light) (e.g., irradiating the first protective film by using a laser beam). For example, the radiation may include or be UV radiation.

[0065] External stimuli may include or be compounds, and / or electronic or plasma radiation, and / or mechanical treatments (such as pressure, friction, or ultrasonic applications), and / or static electricity.

[0066] In some embodiments, applying external stimulation to the first protective film includes or consists of applying pressure to the first protective film, for example, by using a pressure application device (such as a roller, stamp, film, etc.). Alternatively, the first protective film can be attached to one side of the substrate without applying pressure to the first protective film (e.g., by simply placing the first protective film on one side of the substrate). The first protective film can be attached to one side of the substrate without applying heat to the first protective film. The first protective film can be attached to one side of the substrate without applying a vacuum to the first protective film. The first protective film can be attached to one side of the substrate without applying pressure to the first protective film, without applying heat to the first protective film, and without applying a vacuum to the first protective film. The latter approach is particularly advantageous if there are highly fragile and / or sensitive structures (e.g., highly sensitive devices (such as microelectromechanical systems (MEMS))) on the front side of the substrate.

[0067] For example, applying external stimulation to the first protective film may include or consist of applying pressure to the first protective film and applying a vacuum to the first protective film. A vacuum may be applied to the first protective film in a vacuum chamber. Alternatively, the first protective film may be attached to one side of the substrate without applying a vacuum to the first protective film.

[0068] In some embodiments, applying external stimulation to the first protective film includes or consists of heating the first protective film. For example, applying external stimulation to the first protective film may include or consists of heating the first protective film and applying a vacuum to the first protective film. In this case, a vacuum may be applied to the first protective film during, and / or before, and / or after heating the first protective film.

[0069] If applying an external stimulus to the first protective film includes or consists of heating the first protective film, the method may further include allowing the first protective film to cool after the heat treatment. Specifically, the first protective film may be allowed to cool to its initial temperature (i.e., the temperature of the first protective film before the heat treatment). For example, the first protective film may be allowed to cool to its initial temperature before applying a laser beam to the substrate.

[0070] The adhesion force between the first protective film and the substrate is generated by heat treatment. The adhesion of the first protective film to the substrate can be caused by the heat treatment itself and / or by subsequent treatments that allow the first protective film to cool.

[0071] For example, the first protective film can be softened by heat treatment to conform to the substrate surface on one side of the substrate (e.g., to adsorb the substrate morphology). For example, when cooled to the initial temperature of the first protective film, the first protective film can be re-hardened to, for example, form a shape fit and / or material bond with the substrate.

[0072] The first protective film can withstand temperatures up to 180°C or higher, preferably up to 220°C or higher, more preferably up to 250°C or higher, and even more preferably up to 300°C or higher.

[0073] The first protective film can be heated to a temperature in the range of 30°C to 250°C, preferably 50°C to 200°C, more preferably 60°C to 150°C, and even more preferably 70°C to 110°C. Particularly preferably, the first protective film is heated to a temperature of approximately 80°C.

[0074] During and / or after the first protective film is applied to one side of the substrate, the first protective film may be heated for a duration ranging from 30 seconds to 10 minutes, preferably from 1 minute to 8 minutes, more preferably from 1 minute to 6 minutes, even more preferably from 1 minute to 4 minutes, and even more preferably from 1 minute to 3 minutes.

[0075] If the external stimulus applied to the first protective film includes or consists of heating the first protective film, the first protective film can be heated directly and / or indirectly.

[0076] The first protective film can be heated by directly applying heat, for example, using a heat application device (such as a heated roller, a heated die, etc.) or a heat radiation device. By using a combined heat and pressure application device (e.g., a heated roller or a heated die), pressure can be applied to the first protective film while it is being heated. The first protective film and the substrate can be placed in a container or chamber (e.g., a vacuum chamber), and the internal volume of the container or chamber can be heated to heat the first protective film. The container or chamber may be equipped with a heat radiation device.

[0077] Before, and / or during, and / or after the first protective film is applied to one side of the substrate, the first protective film can be indirectly heated, for example, by heating the substrate. For example, the substrate can be heated by placing the substrate on a support or carrier (such as a chuck stage) and heating the support or carrier.

[0078] For example, the support or carrier (such as a chuck table) can be heated to a temperature in the range of 30°C to 250°C, preferably 50°C to 200°C, more preferably 60°C to 150°C, and even more preferably 70°C to 110°C. Particularly preferably, the support or carrier is heated to a temperature of about 80°C.

[0079] These methods can also be combined, for example, by using a heat application device (such as a heated roller) or a heat radiation device to directly heat the first protective film, and also by indirectly heating the first protective film via a substrate.

[0080] If applying external stimulation to the first protective film includes or constitutes heating the first protective film, then the first protective film is preferably bendable, elastic, flexible, stretchable, soft, and / or compressible in its heated state. In this way, it can be reliably ensured that the first protective film conforms to the substrate surface on one side of the substrate (e.g., adhering to the substrate morphology). This is particularly advantageous if there are protrusions or bumps and / or depressions (e.g., grooves, notches, cuts, etc.) on the front side of the substrate.

[0081] Preferably, the first protective film hardens or stiffens at least to some extent upon cooling, so as to become more rigid and / or robust in the cooled state. In this way, particularly reliable protection of the substrate can be ensured during subsequent processing (e.g., applying a laser beam to the substrate).

[0082] At least one dividing line may be formed on one side of the substrate. Multiple dividing lines may be formed on one side of the substrate. One or more dividing lines separate devices formed in the device region.

[0083] The width of at least one dividing line can be in the range of 30μm to 200μm, preferably 30μm to 150μm, and more preferably 30μm to 100μm.

[0084] A laser beam can be applied to a substrate at multiple locations along at least one slit line to form multiple modified regions in the substrate along the slit line. By forming modified regions in this way, the strength of the substrate along at least one slit line is reduced, thus greatly facilitating the slitting of the substrate along at least one slit line.

[0085] The method of the present invention may further include attaching a first protective film to a second protective film to encase or contain a substrate between the first and second protective films. The first protective film may be attached to the second protective film during and / or after attaching the first protective film to the substrate, and / or during and / or after attaching the second protective film to the substrate. The substrate may be sealed between the first and second protective films. The first protective film may be attached to the second protective film at an outer peripheral portion of the first protective film, and / or at an outer peripheral portion of the second protective film.

[0086] By attaching the first and second protective films to each other to encapsulate the substrate between them, the substrate can be reliably protected from damage and contamination (e.g., debris). Furthermore, the risk of any substrate warping during processing can be further reduced or even completely eliminated.

[0087] The first protective film may be attached to the substrate during and / or after the second protective film is attached to the substrate. The second protective film may be attached to the substrate during and / or after the first protective film is attached to the substrate.

[0088] The first protective film can be attached to one side of the substrate, such that the front surface of the first protective film is in direct contact with one side of the substrate throughout the entire area where it contacts the front surface of the first protective film. Therefore, there is no material (especially no adhesive) between the front surface of the first protective film and one side of the substrate.

[0089] In this way, the risk of contamination or damage to the substrate, for example, due to the adhesive force of the adhesive layer or adhesive residue on the substrate, can be eliminated.

[0090] Alternatively, the first protective film may be provided with an adhesive layer, wherein the adhesive layer is provided only in the outer peripheral region of the front surface of the first protective film, the outer peripheral region surrounding the central region of the front surface of the first protective film, and the first protective film is attached to one side of the substrate such that the adhesive layer contacts only the outer peripheral portion of one side of the substrate (e.g., the outer peripheral edge region of the substrate).

[0091] In this way, the adhesion of the first protective film to the substrate can be further improved. Since the adhesive layer is only disposed in the outer peripheral region of the front surface of the first protective film, the area where the first protective film and the substrate are attached to each other by the adhesive layer is significantly reduced compared to the case where the adhesive layer is disposed on the entire front surface of the first protective film. Therefore, the first protective film can be more easily separated from the substrate and the risk of damaging the substrate (especially for devices formed in the device region) is significantly reduced.

[0092] The adhesive layer has an adhesive that can be cured by external stimuli (e.g., heat, UV radiation, electric fields, and / or chemical reagents). In this way, the first protective film can be removed from the substrate particularly easily after processing. External stimuli can be applied to the adhesive to reduce its adhesive strength, thus allowing for easy removal of the first protective film.

[0093] For example, the adhesive layer can have a generally annular shape, an open rectangular shape, or an open square shape, that is, a rectangular or square shape with an opening in the center of the adhesive layer, respectively.

[0094] The second protective film can be attached to the side of the substrate opposite to one side, such that the second protective film (particularly the front surface of the second protective film) contacts the opposite side of the substrate over its entire area, thereby attaching the second protective film to the substrate. In this way, the substrate can be held particularly reliably and firmly by the second protective film, thus allowing the risk of any warping of the substrate during processing to be minimized. Such suppression of substrate warping can be further enhanced by attaching the second protective film to an annular frame and, for example, clamping the annular frame, such that pressure is applied through the second protective film to the rear side of the substrate, as will be described in detail below.

[0095] By attaching the second protective film to the side of the substrate opposite to one side in this manner, for example before, during, and / or after the substrate is diced into chips or dies, the potential unintentional detachment of chips or dies from the substrate from the first protective film can be particularly reliably prevented. For example, when modified regions are formed in the substrate (i.e., prior to the actual substrate dicing process), some of these chips or dies may have already separated from the rest of the substrate. Such chips or dies can be held particularly reliably by the second protective film.

[0096] During and / or after the application of the second protective film to the side of the substrate opposite to one side, the second protective film may be attached to the side of the substrate opposite to one side in the manner described above, for example by providing an adhesive layer over the entire area in contact with the side of the substrate opposite to one side of the second protective film (particularly the front surface of the second protective film), and / or by applying external stimulation to the second protective film. This will be explained in more detail below.

[0097] The second protective film may have an adhesive layer disposed over the entire area where the second protective film (particularly the front surface of the second protective film) contacts the opposite side of the substrate. In this way, the second protective film can be attached to the opposite side of the substrate in a particularly reliable manner by means of this continuous adhesive layer. Furthermore, there is essentially no risk that devices in the device area on one side of the substrate might be damaged or contaminated by the adhesive layer of the second protective film attached to the opposite side of the substrate. The adhesive in the adhesive layer may have the same properties as the adhesive in the adhesive layer of the first protective film. The adhesive in the continuous adhesive layer of the second protective film (if present) is made of a material transparent to the laser beam to be applied to the substrate.

[0098] Alternatively, the second protective film can be attached to the side of the substrate opposite to one side, such that at least the central region of the front surface of the second protective film is in direct contact with the side of the substrate opposite to one side. Therefore, there is no material (especially no adhesive) between the central region of the front surface of the second protective film and the side of the substrate opposite to one side.

[0099] Therefore, the risk of potential contamination or damage to the substrate, such as due to the adhesive force of the adhesive layer or adhesive residue on the substrate, can be further reduced or even completely eliminated. Furthermore, attaching the second protective film to the rear side of the substrate such that at least the central region of the front surface of the second protective film is in direct contact with the rear side allows the laser beam to be applied to the substrate to form multiple modified regions in the substrate in a particularly efficient and accurate manner.

[0100] The second protective film can be attached to the side of the substrate opposite to one side, such that the front surface of the second protective film is in direct contact with the side of the substrate opposite to one side throughout the entire region where the front surface of the second protective film contacts the side of the substrate opposite to one side. Therefore, there is no material (especially no adhesive) between the front surface of the second protective film and the side of the substrate opposite to one side.

[0101] In this way, the risk of contamination or damage to the substrate due to adhesive forces of the adhesive layer or adhesive residue on the substrate can be eliminated. Furthermore, the efficiency and precision of the laser beam that may be applied to the substrate to form multiple modified regions within it can be further improved.

[0102] Alternatively, the second protective film may include an adhesive layer, wherein the adhesive layer is disposed only in the outer peripheral region of the front surface of the second protective film, the outer peripheral region surrounding the central region of the front surface of the second protective film, and the second protective film is applied to the side of the substrate opposite to one side such that the adhesive layer contacts only the outer peripheral portion of the side of the substrate opposite to one side. The outer peripheral portion of the side of the substrate opposite to one side may correspond to the outer peripheral edge region formed on one side of the substrate. The adhesive of the adhesive layer may have the same properties as the adhesive of the adhesive layer of the first protective film.

[0103] In this way, the adhesion of the second protective film to the substrate can be further improved. Since the adhesive layer is only disposed in the outer peripheral region of the front surface of the second protective film, the area where the second protective film and the substrate are attached to each other by the adhesive layer is significantly reduced compared to the case where the adhesive layer is disposed on the entire front surface of the second protective film. Therefore, the second protective film can be separated from the substrate more easily and the risk of damaging the substrate (especially to protrusions or bumps formed on the rear side of the substrate, if present) is significantly reduced.

[0104] Attaching the second protective film to the side of the substrate opposite to one side may include applying the second protective film to the side of the substrate opposite to one side, such that at least a central region of the front surface of the second protective film is in direct contact with the side of the substrate opposite to one side. Therefore, there is no material (particularly no adhesive) between at least a central region of the front surface of the second protective film and the side of the substrate opposite to one side. Furthermore, attaching the second protective film to the side of the substrate opposite to one side may include applying an external stimulus to the second protective film during and / or after applying it to the side of the substrate opposite to one side, such that the second protective film is attached to the side of the substrate opposite to one side. Therefore, the application of the external stimulus creates an adhesive force between the second protective film and the substrate, holding the second protective film in its position on the substrate. Therefore, no additional adhesive material is required to attach the second protective film to the side of the substrate opposite to one side.

[0105] In particular, by applying external stimulation to the second protective film, a shape fit (e.g., positive fit) and / or material bond (e.g., adhesive bond) can be formed between the second protective film and the substrate.

[0106] The external stimuli and the manner in which external stimuli are applied to the second protective membrane can be the same as those described above for the first protective membrane.

[0107] The adhesive layer of the second protective film (e.g., a continuous adhesive layer or an adhesive layer disposed only in the outer peripheral region of the front surface of the second protective film) can be curable by external stimuli (e.g., heat, UV radiation, electric field, and / or chemical reagents). In this way, the second protective film can be removed from the substrate particularly easily after processing. External stimuli can be applied to the adhesive to reduce the adhesive force, thus allowing easy removal of the second protective film. In particular, chips or dies obtained by dicing the substrate can be picked up from the second protective film in a particularly easy manner.

[0108] The rear surface of the substrate can be a generally flat, smooth surface. Alternatively, the rear surface of the substrate may have protrusions or bumps extending from the surface of the planar substrate along the thickness direction of the substrate and / or recesses (such as grooves, notches, cuts, etc.) extending inward from the surface of the planar substrate. The second protective film may be attached to the side of the substrate opposite to one side so as to at least partially follow the contour or morphology of the side of the substrate opposite to one side (e.g., the contour of protrusions or bumps, and / or recesses present on such a substrate side).

[0109] The second protective film can withstand temperatures up to 180°C or higher, preferably up to 220°C or higher, more preferably up to 250°C or higher, and even more preferably up to 300°C or higher.

[0110] If applying external stimulation to the second protective film includes or constitutes heating the second protective film, then the second protective film is preferably bendable, elastic, flexible, stretchable, soft, and / or compressible in its heated state. In this way, it can be reliably ensured that the second protective film conforms to the substrate surface on the side opposite to one side of the substrate (e.g., adhering to the substrate morphology). This is particularly advantageous if there are protrusions or bumps and / or depressions (e.g., grooves, notches, cuts, etc.) on the rear side of the substrate.

[0111] The buffer layer can be attached to the rear surface of the first protective film opposite to its front surface. The buffer layer can be attached to the first protective film at its front surface.

[0112] This method is particularly advantageous if there are protrusions or bumps and / or depressions (e.g., grooves, notches, cuts, etc.) on one side of the substrate. In this case, the protrusions or bumps and / or depressions define the surface structure or morphology of the front side of the substrate, making that side uneven.

[0113] By attaching a buffer layer to the rear surface of the first protective film, substrate surface structures or morphologies (e.g., protrusions or bumps) can be embedded within the buffer layer. Therefore, any negative impact of surface unevenness caused by the presence of protrusions or bumps and / or depressions on subsequent substrate processing (particularly applying a laser beam to the substrate and / or reducing substrate thickness (e.g., by grinding)) can be eliminated. The buffer layer can significantly contribute to achieving a particularly consistent and uniform pressure distribution during processing. For example, by embedding protrusions or bumps in the buffer layer, protrusions or bumps are reliably protected from any damage during substrate processing.

[0114] There are no particular restrictions on the material of the buffer layer. In particular, the buffer layer can be formed of any type of material that allows substrate surface structures or morphologies (e.g., protrusions or bumps) to be embedded therein. For example, the buffer layer can be formed of resin, adhesive, gel, etc.

[0115] The buffer layer can be curable by external stimuli (e.g., UV radiation, heat, electric fields, and / or chemical reagents). In this case, the buffer layer hardens to at least some extent when an external stimulus is applied. For example, the buffer layer can be formed from curable resins, curable adhesives, curable gels, etc.

[0116] The buffer layer can be configured to exhibit a degree of compressibility, elasticity, and / or flexibility after curing (i.e., it is compressible, elastic, and / or flexible after curing). For example, the buffer layer can be configured to enter a rubbery state upon curing. Alternatively, the buffer layer can be configured to reach a rigid, hard state after curing.

[0117] Preferred examples of UV-curable resins used as buffer layers in the methods of the present invention are ResiFlat from DISCO and TEMPLOC from DENKA.

[0118] The method may also include, for example, applying an external stimulus to the buffer layer to cure the buffer layer before applying a laser beam to the substrate and / or reducing the substrate thickness (e.g., by grinding). In this way, protection of the substrate during laser beam application is improved, and the efficiency and precision of forming multiple modified regions in the substrate are further enhanced.

[0119] The buffer layer can withstand temperatures up to 180°C or higher, preferably up to 220°C or higher, more preferably up to 250°C or higher, and even more preferably up to 300°C or higher.

[0120] The buffer layer may have a thickness in the range of 10 to 300 μm, preferably 20 to 250 μm and more preferably 50 to 200 μm.

[0121] Before applying or attaching the first protective film to one side of the substrate, a buffer layer may be attached to the rear surface of the first protective film.

[0122] In this configuration, a first protective film and a buffer layer can first be laminated to form a protective sheet comprising a buffer layer and a first protective film attached to the buffer layer. The protective sheet formed in this manner can then be applied to one side of a substrate, for example, such that the substrate surface structure or morphology (e.g., protrusions or bumps) is covered by the first protective film and embedded within the first protective film and the buffer layer. The protective sheet can be applied such that the rear surface of the buffer layer, opposite to the front surface of the buffer layer, is substantially parallel to the side of the substrate opposite to one side. When the protective sheet is applied to one side of the substrate, the front surface of the first protective film is also applied to one side of the substrate.

[0123] In this way, substrate processing methods can be performed in a particularly simple and efficient manner. For example, protective sheets can be prepared in advance, stored for later use, and used for substrate processing when needed. Therefore, protective sheets can be mass-produced, making their production particularly efficient in terms of time and cost.

[0124] After the first protective film is applied or attached to one side of the substrate, a buffer layer can be attached to the rear surface of the first protective film.

[0125] In this configuration, a first protective film is first applied to one side of the substrate. Then, the side of the substrate with the first protective film applied is attached to the front surface of the buffer layer. For example, the substrate surface structure or morphology (e.g., protrusions or bumps) is embedded in the first protective film and the buffer layer, and the rear surface of the buffer layer is substantially parallel to the side of the substrate opposite to one side. This method allows the first protective film to be attached to one side of the substrate with exceptionally high precision (particularly relative to the substrate surface structure or morphology).

[0126] Before, and / or during, and / or after attaching the first protective film to one side of the substrate, a buffer layer may be attached to the rear surface of the first protective film.

[0127] The substrate can be attached to the rear surface of the buffer layer (i.e., to the surface of the buffer layer opposite to the front surface of the buffer layer). The front surface of the buffer layer is attached to the first protective film.

[0128] There are no particular restrictions on the material of the substrate. The substrate can be made of soft or flexible materials, such as polymer materials, such as polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), or polyolefins.

[0129] Alternatively, the substrate may be made of rigid or hard materials, such as polyethylene terephthalate (PET), and / or silicone, and / or glass, and / or stainless steel (SUS).

[0130] For example, if the substrate is made of polyethylene terephthalate (PET) or glass and the buffer layer is curable by external stimulation, the buffer layer can be cured using radiation (e.g., ultraviolet radiation) that can be transmitted through the polyethylene terephthalate (PET) or glass. If the substrate is made of silicon or stainless steel (SUS), a cost-effective substrate is provided.

[0131] In addition, the substrate can be formed from a combination of the materials listed above.

[0132] The substrate can withstand temperatures up to 180°C or higher, preferably up to 220°C or higher, more preferably up to 250°C or higher, and even more preferably up to 300°C or higher.

[0133] The substrate may have a thickness in the range of 30 to 1500 μm, preferably 40 to 1200 μm and more preferably 50 to 1000 μm.

[0134] Before or after applying the first protective film to one side of the substrate, a buffer layer and a substrate can be attached to the rear surface of the first protective film. Specifically, the first protective film, the buffer layer, and the substrate can first be laminated to form a protective sheet comprising the substrate, the buffer layer, and the first protective film attached to the buffer layer. The protective sheet formed in this manner can then be applied to the front side of the substrate.

[0135] The front surface of the substrate can contact the rear surface of the buffer layer, and the rear surface of the substrate opposite to the front surface can be substantially parallel to the side of the substrate opposite to one side. Therefore, when processing the substrate, appropriate counter-pressure can be applied to the rear surface of the substrate, for example, by placing the rear surface on a support or carrier (e.g., a chuck stage).

[0136] In this configuration, because the flat rear surface of the substrate is substantially parallel to the rear surface of the substrate, the pressure applied to the substrate during processing is distributed more evenly and consistently across the substrate, thus minimizing any risk of substrate breakage. Furthermore, the substantially parallel alignment of the flat, uniform rear surface of the substrate with the rear side of the substrate allows for the application of a laser beam with exceptionally high precision to form multiple modified regions within the substrate, thereby enabling the production of high-quality dies or chips with well-defined shapes and dimensions.

[0137] The method may further include grinding, and / or polishing (e.g., dry polishing), and / or etching (e.g., plasma etching) a side of the substrate opposite to one side, particularly before applying or attaching the second protective film to the substrate. The side of the substrate opposite to one side may be ground to adjust the substrate thickness.

[0138] The second protective film can be expandable.

[0139] When the second protective film is applied to the side of the substrate opposite to one side, the second protective film can be expanded. In particular, when the second protective film is applied to the side of the substrate opposite to one side, the second protective film can be expanded so that it at least partially follows the contour or shape of the side of the substrate opposite to one side (e.g., the contour of protrusions or bulges and / or recesses present on such a substrate side).

[0140] For example, the second protective film can be expanded to more than twice its original size, preferably more than three times its original size, and more preferably more than four times its original size. In this way, especially for the case of expansion to more than three or four times its original size, it can be reliably ensured that the second protective film conforms to the contour or morphology of the side of the substrate opposite to one side.

[0141] If the second protective film is expandable, it can be used to separate devices from each other. Specifically, the method may further include radially expanding the second protective film to separate the devices from each other after applying a laser beam to the substrate from a side opposite to one side. The second protective film can be radially expanded after the first protective film is removed from the front side of the substrate. By radially expanding the second protective film, the substrate can be segmented (e.g., broken) along one or more regions of a plurality of modified regions already formed in the substrate (e.g., along at least one dividing line) to obtain individual chips or dies. By radially expanding the second protective film, an external force is applied to the substrate, thus segmenting the substrate where its strength has been reduced due to the presence of modified regions. After segmenting the substrate in this way, the resulting chips or dies can be picked up directly from the second protective film, for example, using a pick-up device.

[0142] Alternatively, if the first protective film is expandable, it can be used to separate devices from each other. In this case, the method may further include radially expanding the first protective film after a laser beam is applied to the substrate to separate the devices from each other. The first protective film can be radially expanded after the second protective film is removed from the back side of the substrate. Thus, by radially expanding the first protective film, the substrate can be segmented (e.g., broken) along one or more regions of a plurality of modified regions already formed in the substrate (e.g., along at least one dividing line) to obtain individual chips or dies. For example, as described in detail above, the latter method may be employed in a particularly advantageous manner if the first protective film has been attached to one side of the substrate by applying heat and / or pressure to it. After the substrate is segmented in this way, the resulting chips or dies can be picked up directly from the first protective film, for example, by using a pick-up device.

[0143] As an alternative to radially expanding the first or second protective film, for example, after removing the second protective film, a separate expansion tape can be attached to the back of the substrate. Subsequently, the devices can be separated from each other by radially expanding the expansion tape.

[0144] If the first or second protective film is used to separate the devices from each other, there is no need to remount the substrate to different films or tapes (e.g., separate expansion tapes) to divide the substrate. Therefore, the substrate can be divided in a particularly efficient manner. Furthermore, the risk of any damage to the substrate and / or the resulting chips or dies, for example, due to chips or dies inadvertently detaching from their supports, can be further reduced.

[0145] The method of the present invention may further include attaching a first protective film and / or a second protective film to an annular frame. For example, the first protective film may be attached to a first annular frame and the second protective film may be attached to a second annular frame (i.e., attached to another annular frame). Alternatively, the first and second protective films may be attached to the same annular frame (i.e., attached to a single annular frame).

[0146] Specifically, the outer peripheral portion of the first protective film can be attached to the annular frame. The first protective film can be attached to the annular frame such that it closes the central opening of the annular frame (i.e., the region inside the inner diameter of the annular frame). In this way, the substrate attached to the first protective film (particularly the central portion of the first protective film) is held by the annular frame through the first protective film. Thus, a substrate unit comprising the substrate, the first protective film, and the annular frame is formed, facilitating the handling, manipulation, and / or transport of the substrate.

[0147] The step of attaching the outer peripheral portion of the first protective film to the annular frame can be performed before, during, or after the first protective film is applied to or attached to the substrate.

[0148] The step of attaching the outer peripheral portion of the first protective film to the annular frame can be performed before or after the laser beam is applied to the substrate.

[0149] The outer peripheral portion of the second protective film can be attached to the annular frame. The second protective film can be attached to the annular frame such that it closes the central opening of the annular frame (i.e., the region inside the inner diameter of the annular frame). In this way, the substrate attached to the second protective film (particularly the central portion attached to the second protective film) is held by the annular frame through the second protective film. Therefore, a substrate unit comprising the substrate, the second protective film, and the annular frame is formed, facilitating the handling, manipulation, and / or transport of the substrate.

[0150] The step of attaching the outer peripheral portion of the second protective film to the annular frame can be performed before, during, or after the application or attachment of the second protective film to the substrate.

[0151] The step of attaching the outer peripheral portion of the second protective film to the annular frame can be performed before or after the laser beam is applied to the substrate.

[0152] The annular frame attached to the first and / or second protective film can further facilitate the processing of the substrate. For example, if the second protective film is expandable and attached to the annular frame, the second protective film can be expanded (e.g., by moving the annular frame and the expansion drum relative to each other in a conventional manner) to separate the devices from each other. If the first protective film is expandable and attached to the annular frame, the first protective film can be expanded (e.g., by moving the annular frame and the expansion drum relative to each other in a conventional manner) to separate the devices from each other.

[0153] The method of the present invention may further include removing a first protective film from one side of a substrate. The first protective film can be removed from one side of the substrate after a laser beam is applied to the substrate. The first protective film can be removed from one side of the substrate before radially expanding a second protective film to separate the devices from each other.

[0154] The method may further include removing a first protective film, a buffer layer (if present), and a substrate (if present) from one side of the substrate. The first protective film, buffer layer, and substrate can be removed from one side of the substrate after a laser beam is applied to the substrate. The first protective film, buffer layer, and substrate can be removed from one side of the substrate before radially expanding a second protective film to separate the devices from each other.

[0155] The substrate, buffer layer, and first protective film can be removed from the substrate individually (i.e., sequentially). For example, the substrate can be removed first, then the buffer layer, and subsequently the first protective film. Alternatively, the substrate, buffer layer, and first protective film can be removed from the substrate together. Furthermore, the substrate can be removed together with the buffer layer, or the buffer layer can be removed together with the first protective film.

[0156] The method of the present invention may further include removing a second protective film from a side of the substrate opposite to one side. The second protective film can be removed from the side of the substrate opposite to one side after a laser beam is applied to the substrate. The second protective film can be removed from the side of the substrate opposite to one side before radially expanding the first protective film to separate the devices from each other. Attached Figure Description

[0157] In the following description, non-limiting examples of the invention are illustrated with reference to the accompanying drawings, in which:

[0158] Figure 1 This is a cross-sectional view of a wafer used as a substrate, processed by the method of the present invention;

[0159] Figure 2 This is a cross-sectional view showing the result of attaching a second protective film to a wafer according to a first embodiment of the method of the present invention;

[0160] Figure 3 This is a cross-sectional view showing the result of attaching a first protective film to a wafer according to a first embodiment of the method of the present invention;

[0161] Figure 4 This is a cross-sectional view illustrating the step of applying a laser beam to a wafer according to a first embodiment of the method of the present invention;

[0162] Figure 5 This is a cross-sectional view illustrating the step of applying a laser beam to a wafer, according to a modification of a first embodiment of the method of the present invention;

[0163] Figure 6 This is a cross-sectional view illustrating the step of radially expanding a second protective film according to a first embodiment of the method of the present invention to separate the devices on the wafer from each other;

[0164] Figure 7 This is a cross-sectional view showing the result of attaching a first protective film to a wafer according to a second embodiment of the method of the present invention;

[0165] Figure 8 This is a cross-sectional view showing the result of attaching the first protective film to the wafer in a modified second embodiment of the method according to the present invention;

[0166] Figure 9 This is a cross-sectional view illustrating the step of applying a laser beam to a wafer according to a second embodiment of the method of the present invention;

[0167] Figure 10 This is a cross-sectional view showing the result of attaching a first protective film to a wafer according to a third embodiment of the method of the present invention;

[0168] Figure 11 This is a cross-sectional view showing the result of a wafer grinding step according to a third embodiment of the method of the present invention;

[0169] Figure 12 This is a cross-sectional view illustrating the steps of attaching a second protective film to a wafer according to a third embodiment of the method according to the present invention, and illustrating the result of applying a laser beam to the wafer;

[0170] Figure 13 This is a cross-sectional view illustrating the steps of attaching a second protective film to a wafer in a third embodiment of the method according to the invention, and illustrating the result of applying a laser beam to the wafer;

[0171] Figure 14 This is a cross-sectional view illustrating the step of radially expanding the second protective film to separate the devices on the wafer from each other, according to a third embodiment of the method of the present invention.

[0172] Figure 15 This is a cross-sectional view illustrating a modified radial expansion of the first protective film according to a third embodiment of the method of the present invention in order to separate the devices on the wafer from each other.

[0173] Figure 16 This is a cross-sectional view showing the result of a modified cutting step of attaching a first protective film to a wafer according to a third embodiment of the method of the present invention; and

[0174] Figure 17 The diagram shows the results of a modified wafer grinding step according to a third embodiment of the method of the present invention, the results of a step of attaching a second protective film to the wafer, and a cross-sectional view illustrating the step of applying a laser beam to the wafer. Detailed Implementation

[0175] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. The preferred embodiments relate to a method of processing a substrate.

[0176] In this embodiment, the method of the present invention is performed on a wafer W, which serves as a substrate to be processed. Wafer W may be a semiconductor wafer (e.g., a Si wafer). Specifically, wafer W may be a single-crystal Si wafer. However, different types of substrates, particularly substrates made of different substrate materials, as described in detail above, may be used.

[0177] For example, the wafer W may have a thickness in the range of μm before grinding, preferably in the range of 625 to 925 μm. In this embodiment, the wafer W presents a generally circular shape when viewed from above. However, the shape of the wafer W is not particularly limited. In other embodiments, the wafer W may have, for example, an oval shape, an elliptical shape, or a polygonal shape (such as a rectangular or square shape).

[0178] Wafer W has one side (i.e., front side 2) and the opposite side (i.e., back side 4) (see...). Figure 1 A device region 6 having a plurality of devices 8 is formed on the front side 2 of wafer W. The devices 8 may be, for example, semiconductor devices, power devices, optical devices, medical devices, electronic components, MEMS devices, or combinations thereof. The devices 8 may include, for example, transistors (such as MOSFETs or insulated gate bipolar transistors (IGBTs)) or diodes (e.g., Schottky barrier diodes).

[0179] In this embodiment, device region 6 has a generally circular shape and is arranged concentrically with the outer circumference of wafer W. Device region 6 is surrounded by an annular outer peripheral edge region 10 (see...). Figure 1No device is formed in this outer peripheral edge region 10. The outer peripheral edge region 10 is arranged concentrically with the outer circumference of the device region 6 and the wafer W. The outer peripheral edge region 10 can extend radially within a range of mm, and preferably within a range of 1 mm to 3 mm.

[0180] Multiple dividing lines 12 are formed on the front side 2 of the wafer W. The dividing lines 12 are arranged in a grid pattern to divide the front side 2 into multiple rectangular regions. A device 8 is disposed in each of these regions. The dividing lines 12 may have a width in the range of 30 to 200 μm, preferably 30 to 150 μm, and more preferably 30 to 100 μm.

[0181] Below, we will refer to Figures 1 to 6 A method for processing wafer W according to a first embodiment of the present invention is described.

[0182] In this embodiment, the second protective film 14 is first attached to the back side 4 of the wafer W. The result of this attachment step is... Figure 2 As shown in the figure. For example, the second protective film 14 can be made of polyolefin (such as polyethylene (PE), polypropylene (PP) or polybutene (PB)). The second protective film 14 can have a thickness in the range of 5 to 500 μm, preferably 5 to 200 μm, more preferably 8 to 100 μm, even more preferably 10 to 80 μm and even more preferably 12 to 50 μm.

[0183] The second protective film 14 has a generally circular shape and an outer diameter larger than that of the wafer W. The outer peripheral portion 16 of the second protective film 14 is attached to the annular frame 18 (see...). Figure 2 The second protective film 14 may be attached to the annular frame 18 before, during, or after attaching it to the wafer W. The second protective film 14 may be attached to the annular frame 18, for example, by means of an adhesive (not shown). The wafer W and the annular frame 18 are attached to the same surface of the second protective film 14 (i.e., to the front surface 20 of the second protective film 14).

[0184] The second protective film 14 can be attached to the back side 4 of the wafer W by employing one of the methods described in detail above, such as by using a continuous adhesive layer (not shown), by using an adhesive layer (not shown) disposed only in the outer peripheral region of the front surface 20 of the second protective film 14, or by not using an adhesive. In the latter two cases, attaching the second protective film 14 to the back side 4 of the wafer W may include applying an external stimulus (e.g., heat, and / or pressure, and / or vacuum) to the second protective film 14 during and / or after applying the second protective film 14 to the back side 4, as described above.

[0185] After attaching the second protective film 14 to the back side 4 of wafer W, the first protective film 22 is attached to wafer W. The result of this attachment step is as follows: Figure 3 As shown, a first protective film 22 is attached to the front side 2 of the wafer W such that the central region of the front surface 24 of the first protective film 22 is in direct contact with the front side 2. Therefore, there is no material (especially no adhesive) between the central region of the front surface 24 of the first protective film 22 and the front side 2.

[0186] For example, the first protective film 22 may be made of a polyolefin (such as polyethylene (PE), polypropylene (PP) or polybutene (PB)). The first protective film 22 may have a thickness in the range of 5 to 500 μm, preferably 5 to 200 μm, more preferably 8 to 100 μm, even more preferably 10 to 80 μm and even more preferably 12 to 50 μm.

[0187] The first protective film 22 has a generally circular shape and an outer diameter that is approximately the same as the outer diameter of the wafer W. The first protective film 22 covers the device 8 formed in the device region 6.

[0188] The first protective film 22 is provided with an adhesive layer 26 (see...) Figure 3 The adhesive layer 26 is disposed only in the outer peripheral region of the front surface 24 of the first protective film 22, the outer peripheral region surrounding the central region of the front surface 24. The adhesive layer 26 has a generally annular shape. The first protective film 22 is attached to the front side 2 of the wafer W such that the adhesive layer 26 contacts only the outer peripheral portion of the front side 2 of the wafer W (i.e., contacts the outer peripheral edge region 10) (see...). Figure 1 The adhesive of adhesive layer 26 may be curable by external stimuli (e.g., heat, UV radiation, electric field and / or chemical reagents).

[0189] Furthermore, during and / or after applying the first protective film 22 to the front side 2 of the wafer W, an external stimulus may be applied to the first protective film 22, causing the first protective film 22 to be attached to the front side 2, also in the central region of the front surface 24 where no adhesive is present. The application of the external stimulus creates adhesion between the first protective film 22 and the wafer W in the central region of the front surface 24. The type of external stimulus and the manner in which the external stimulus is applied to the first protective film 22 can be as described above. For example, the external stimulus may include or be heat, and / or pressure, and / or vacuum.

[0190] In other embodiments, an adhesive layer may not be provided on the front surface 24 of the first protective film 22, allowing the entire front surface 24 of the first protective film 22 to be in direct contact with the front side 2 of the wafer W. In this case, the first protective film 22 can be attached to the front side 2 by applying external stimulation, as described in detail above.

[0191] In other embodiments, a buffer layer (not shown) may be attached to a rear surface 28 of the first protective film 22 opposite to its front surface 24, as described in detail above. A substrate (not shown) may be attached to the rear surface of the buffer layer, as also described in detail above.

[0192] After attaching the first protective film 22 and the second protective film 14 to the wafer W, the wafer W is placed on the chuck stage 30 such that the rear surface 28 of the first protective film 22 contacts the upper surface of the chuck stage 30. Therefore, the rear surface 4 of the wafer W, on which the second protective film 14 is attached, faces upward. Subsequently, a laser beam LB is applied to the wafer W from the rear side 4, as... Figure 4 As shown. The second protective film 14 is made of a material that is transparent to the laser beam LB. Therefore, the laser beam LB is transmitted through the second protective film 14.

[0193] In this embodiment, the laser beam LB is a pulsed laser beam, for example, having a pulse width in the range of 1 fs to 2000 ns. The wafer W is made of a material (e.g., Si) that is transparent to the laser beam LB. The laser beam LB is applied to the wafer W at multiple locations along the cleaving line 12 to form multiple modified regions (not shown) in the wafer W along the cleaving line 12. The laser beam LB is applied to the wafer W at multiple locations where the focal point is located within the body of the wafer W. The modified regions may include or may be amorphous regions and / or regions in which cracks are formed. Preferably, the modified regions include or may be amorphous regions.

[0194] During the application of the laser beam LB to the wafer W, the wafer W is reliably held by the second protective film 14 attached thereto (see...). Figure 4 Therefore, any warping of the wafer W during this process can be suppressed or even completely avoided, allowing for a significant improvement in the precision of the modified regions formed within the wafer W. In particular, the modified regions can be formed consistently at the same depth within the wafer W (i.e., at the same locations along the thickness direction of the wafer W).

[0195] Figure 5 This is a cross-sectional view illustrating the step of applying a laser beam LB to wafer W according to a modified first embodiment of the method of the present invention. In this modified method, the annular frame 18 is displaced relative to wafer W and chuck stage 30 in a vertically downward direction, as shown below. Figure 5 As indicated by the two arrows. For example, for this purpose, the annular frame 18 can be clamped downwards. Therefore, as... Figure 5As shown, the outer peripheral portion 16 of the second protective film 14 is displaced accordingly, and pressure is applied to the rear side 4 of the wafer W through the second protective film 14. In this way, any risk of warpage of the wafer W can be minimized during the application of the laser beam LB to the wafer W.

[0196] For example, depending on the material and / or thickness of the wafer W and processing parameters (e.g., the number or areal density of the modified regions to be formed in the wafer W), the annular frame 18 can be displaced to varying degrees relative to the wafer W and the chuck stage 30 in a vertically downward direction. In this way, the pressure applied by the second protective film 14 to the rear side 4 of the wafer W can be appropriately controlled. The annular frame 18 can be displaced relative to the wafer W and the chuck stage 30 to such a degree that the front surface 20 of the second protective film 14 (optionally having an adhesive layer disposed thereon) contacts the upper surface of the chuck stage 30, such as... Figure 5 As shown. This method provides the additional advantage that the wafer W can be completely encapsulated between the second protective film 14 and the chuck stage 30, allowing for particularly reliable protection of the wafer W from damage and contamination.

[0197] After the modified region has been formed in wafer W, the first protective film 22 is removed from the front side 2 of wafer W. If the adhesive of the adhesive layer 26 is curable by external stimulation, the removal process can be facilitated by applying external stimulation to the adhesive to reduce the adhesive force.

[0198] After the first protective film 22 is removed from wafer W, wafer W is diced into individual dies 32 (see [link]). Figure 6 Specifically, for example, the second protective membrane 14 (an expandable membrane) is radially expanded by moving the annular frame 18 and the expansion drum (not shown) relative to each other in a conventional manner, as... Figure 6 As indicated by the two arrows in the diagram, an external force is applied to the wafer W by radially expanding the second protective film 14, thus dividing the wafer W along the cleaving line 12, where the wafer strength has been reduced due to the presence of the modified region. In this way, a completely separated die 32 is obtained. After the wafer W is divided in this manner, the resulting die 32 can be picked up directly from the second protective film 14, for example, using a conventional pick-up device (not shown).

[0199] Below, we will refer to Figures 7 to 9 A method for processing wafer W according to a second embodiment of the present invention is described.

[0200] The method of the second embodiment differs from that of the first embodiment in the configuration and arrangement of the first protective film 22. In the description of the second embodiment, elements similar to or substantially the same as those in the first embodiment are indicated by the same reference numerals, and repeated detailed descriptions are omitted.

[0201] In the second embodiment, the second protective film 14 is attached to the wafer W in the same manner as in the first embodiment (see [link to first embodiment]). Figure 2 Subsequently, the first protective film 22 is attached to the wafer W. The result of this attachment step is... Figure 7 As shown in the figure, a first protective film 22 is attached to the front side 2 of the wafer W such that the central region of the front surface 24 of the first protective film 22 is in direct contact with the front side 2. The material and thickness of the first protective film 22 used in the method of the second embodiment can be the same as those used in the method of the first embodiment.

[0202] The first protective film 22 has a generally circular shape and an outer diameter larger than that of the wafer W. The first protective film 22 covers the device 8 formed in the device region 6.

[0203] The first protective film 22 is provided with an adhesive layer 26 (see...) Figure 7 The adhesive layer 26 is disposed only in the outer peripheral region of the front surface 24 of the first protective film 22, the outer peripheral region surrounding the central region of the front surface 24. The adhesive layer 26 has a generally annular shape. The first protective film 22 is attached to the front side 2 of the wafer W such that the adhesive layer 26 contacts only the outer peripheral portion of the front side 2 of the wafer W (i.e., contacts the outer peripheral edge region 10) (see...). Figure 1 The adhesive of adhesive layer 26 is curable by external stimuli (e.g., heat, UV radiation, electric field and / or chemical reagents).

[0204] Furthermore, the first protective film 22 is attached to the second protective film 14 by means of an adhesive layer 26, thereby encapsulating the wafer W between the first protective film 22 and the second protective film 14. Thus, the adhesive layer 26 forms a seal around the outer circumference of the wafer W. Therefore, the wafer W can be reliably protected from damage and contamination.

[0205] In other embodiments, at least in the area where the front surface 24 of the first protective film 22 contacts the second protective film 14, an adhesive layer may not be provided on the front surface 24 of the first protective film 22. In this case, the adhesive layer of the first protective film 22 can be attached to the second protective film 14 by means of an adhesive layer (not shown) provided on the front surface 20 of the second protective film 14.

[0206] Furthermore, the first protective film 22 is attached to the annular frame 18 (i.e., to the same annular frame 18 as the second protective film 14) by means of an adhesive layer 26. Thus, a particularly stable and reliable wafer cell comprising the wafer W, the first protective film 22, the second protective film 14, and the annular frame 18 is formed. Alternatively, the first protective film 22 can be attached to a different annular frame (not shown).

[0207] During or after attaching the first protective film 22 to the wafer W, the first protective film 22 may be attached to the second protective film 14 and the annular frame 18.

[0208] In the same manner as the method of the first embodiment described in detail above, during and / or after the application of the first protective film 22 to the front side 2 of the wafer W, an external stimulus may be applied to the first protective film 22 such that the first protective film 22 is also attached to the front side 2 in the central region of the front surface 24 where no adhesive is present.

[0209] In other embodiments, the first protective film 22 may be attached to the front side 2 of the wafer W such that the front surface 24 of the first protective film 22 is in direct contact with the front side 2 over the entire region where it contacts the front side 2. In this case, the first protective film 22 may be attached to the front side 2 by applying an external stimulus to it, as described in detail above.

[0210] In other embodiments, a buffer layer (not shown) may be attached to a rear surface 28 of the first protective film 22 opposite to its front surface 24, as described in detail above. A substrate (not shown) may be attached to the rear surface of the buffer layer, as also described in detail above.

[0211] Figure 8 This is a cross-sectional view showing the result of attaching the first protective film 22 to the wafer W in a modified second embodiment of the method according to the invention. In this modified method, the first protective film 22 has a reduced outer diameter that does not extend to the annular frame 18. However, in another modified embodiment, the first protective film 22 is attached to the second protective film 14 by means of an adhesive layer 26 so as to encapsulate the wafer W between the first protective film 22 and the second protective film 14.

[0212] After attaching the first protective film 22 and the second protective film 14 to the wafer W, the wafer W is placed on the chuck stage 30 such that the rear surface 28 of the first protective film 22 contacts the upper surface of the chuck stage 30. Subsequently, a laser beam LB is applied to the wafer W from the rear side 4 in the same manner as in the first embodiment. Figure 9 As shown in the diagram, a laser beam LB is applied to wafer W at multiple locations along the cleaving line 12 to form multiple modified regions (not shown) in wafer W along the cleaving line 12.

[0213] In the method of the first embodiment, the laser beam LB can be applied to the wafer W while the annular frame 18 is already displaced in the vertically downward direction relative to the wafer W and the chuck stage 30 (e.g., by clamping the annular frame 18 downward).

[0214] After the modified region has been formed in wafer W, the first protective film 22 is removed from the front side 2 of wafer W. Subsequently, wafer W is diced into individual dies 32 in the same manner as in the first embodiment (i.e., by radially expanding the second protective film 14) (see...). Figure 6 For example, the obtained bare wafer 32 can be picked up directly from the second protective film 14 using a conventional pickup device (not shown).

[0215] Below, we will refer to Figures 10 to 17 A method for processing wafer W according to a third embodiment of the present invention is described.

[0216] The method of the third embodiment differs from that of the first and second embodiments in the order in which the first protective film 22 and the second protective film 14 are attached to the wafer W. In the description of the third embodiment, elements similar to or substantially the same as those in the first and second embodiments are indicated by the same reference numerals, and repeated detailed descriptions thereof are omitted.

[0217] In the method of the third embodiment, the first protective film 22 is first attached to the front side 2 of the wafer W. The result of this attachment step is as follows: Figure 10 As shown. The material and thickness of the first protective film 22 used in the method of the third embodiment can be the same as those used in the methods of the first and second embodiments. The first protective film 22 is attached to the front side 2 of the wafer W such that the central region of the front surface 24 of the first protective film 22 is in direct contact with the front side 2. The first protective film 22 covers the device 8 formed in the device region 6.

[0218] The first protective film 22 has a generally circular shape and an outer diameter larger than that of the wafer W. The outer peripheral portion 34 of the first protective film 22 is attached to the annular frame 18 (see...). Figure 10 The first protective film 22 can be attached to the annular frame 18 before, during, or after attaching it to the wafer W. The first protective film 22 can be attached to the annular frame 18 by means of adhesive 26. The wafer W and the annular frame 18 are attached to the same surface of the first protective film 22 (i.e., to the front surface 24 of the first protective film 22).

[0219] The adhesive layer 26 of the first protective film 22 is disposed only in the outer peripheral region of the front surface 24 of the first protective film 22, the outer peripheral region surrounding the central region of the front surface 24. The adhesive layer 26 has a generally annular shape. The first protective film 22 is attached to the front side 2 of the wafer W such that the adhesive layer 26 contacts only the outer peripheral portion of the front side 2 of the wafer W (i.e., contacts the outer peripheral edge region 10) (see...). Figure 1The adhesive of adhesive layer 26 may be curable by external stimuli (e.g., heat, UV radiation, electric field and / or chemical reagents).

[0220] Furthermore, during and / or after applying the first protective film 22 to the front side 2 of the wafer W, an external stimulus may be applied to the first protective film 22 such that the central region of the first protective film 22 on the front surface 24 where no adhesive is present is also attached to the front side 2. The type of external stimulus and the manner in which the external stimulus is applied to the first protective film 22 can be as described above. For example, the external stimulus may include or may be heat, and / or pressure, and / or vacuum.

[0221] In other embodiments, the first protective film 22 may be attached to the front side 2 of the wafer W such that the front surface 24 of the first protective film 22 is in direct contact with the front side 2 over the entire region where it contacts the front side 2. In this case, the first protective film 22 may be attached to the front side 2 by applying an external stimulus to it, as described in detail above.

[0222] In other embodiments, a buffer layer (not shown) may be attached to a rear surface 28 of the first protective film 22 opposite to its front surface 24, as described in detail above. A substrate (not shown) may be attached to the rear surface of the buffer layer, as also described in detail above.

[0223] Subsequently, as an optional step, the back side 4 of wafer W can be ground, for example, using a conventional grinding apparatus (not shown), to adjust the wafer thickness. The result of this grinding step is as follows: Figure 11 As shown. Optionally, after the grinding step, the back side 4 of the wafer may be polished (e.g., dry polishing) and / or etched (e.g., plasma etching).

[0224] Then, the second protective film 14 is attached to the back side 4 of the ground, and optionally polished and / or etched wafer W. The result of this attachment step is as follows: Figure 12 As shown. The material and thickness of the second protective film 14 used in the method of the third embodiment can be the same as those used in the methods of the first and second embodiments.

[0225] The second protective film 14 has a generally circular shape and an outer diameter larger than that of the wafer W. The second protective film 14 is attached to the back side 4 of the wafer W in the same manner as in the first embodiment. Furthermore, the outer peripheral portion 16 of the second protective film 14 is attached to the annular frame 18, for example, by means of an adhesive (not shown). Thus, the second protective film 14 is attached to the same annular frame 18 as the first protective film 22. Alternatively, the second protective film 14 can be attached to a different annular frame (not shown).

[0226] The first protective film 22 and the second protective film 14 are attached to each other by means of adhesive layer 26 so as to encapsulate the wafer W between the first protective film 22 and the second protective film 14 (see Figure 12 Therefore, the adhesive layer 26 forms a seal around the outer periphery of the wafer W.

[0227] In other embodiments, at least in the area where the front surface 24 of the first protective film 22 contacts the second protective film 14, an adhesive layer may not be provided on the front surface 24 of the first protective film 22. In this case, the adhesive layer of the first protective film 22 can be attached to the second protective film 14 by means of an adhesive layer (not shown) provided on the front surface 20 of the second protective film 14.

[0228] During or after attaching the second protective film 14 to the wafer W, the second protective film 14 may be attached to the first protective film 22 and the annular frame 18.

[0229] Figure 13 This is a cross-sectional view showing the result of attaching the second protective film 14 to the wafer W in a modified third embodiment of the method according to the invention. In this modified method, the second protective film 14 has a reduced outer diameter that does not extend to the annular frame 18. However, in another modified embodiment, the first protective film 22 and the second protective film 14 adhesive layers are attached to each other by means of an adhesive layer 26 in order to encapsulate the wafer W between the first protective film 22 and the second protective film 14.

[0230] After attaching the first protective film 22 and the second protective film 14 to the wafer W, the laser beam LB is applied to the wafer W from the rear side 4 in the same manner as in the first embodiment, as follows. Figure 12 and Figure 13 As shown. A laser beam LB is applied to wafer W at multiple locations along the cleaving line 12 to form multiple modified regions (not shown) in wafer W along the cleaving line 12.

[0231] After the modified region has been formed in wafer W, the first protective film 22 is removed from the front side 2 of wafer W. Subsequently, wafer W is diced into individual dies 32 in the same manner as in the first embodiment (i.e., by radially expanding the second protective film 14), as... Figure 14 As indicated by the two arrows in the diagram. For example, the obtained bare wafer 32 can be picked up directly from the second protective film 14 using a conventional pickup device (not shown).

[0232] Figure 15This is a modified cross-sectional view illustrating a third embodiment of the method of the present invention. In this modified method, after the modified region is formed in the wafer W, the first protective film 22 remains on the wafer W and the second protective film 14 is removed from the wafer W. Subsequently, the first protective film 22 (expandable film) is radially expanded by moving the annular frame 18 and the expansion drum (not shown) relative to each other in a conventional manner, as shown. Figure 15 As indicated by the two arrows in the diagram, an external force is applied to the wafer W by radially expanding the first protective film 22, thus dividing the wafer W along the cleaving line 12, where the wafer strength has been reduced due to the presence of the modified region. In this way, completely separated dies 32 are obtained. After dividing the wafer W in this manner, the resulting die 32 can be picked up directly from the first protective film 22, for example, using a conventional pick-up device (not shown).

[0233] For example, if the first protective film 22 has already been attached to the front side 2 of the wafer W by applying an external stimulus (such as heat, and / or pressure, and / or vacuum) to the first protective film 22, as described in detail above, it can be employed in a particularly advantageous manner. Figure 15 The modification method is illustrated in the diagram. Furthermore, for example, if the second protective film 14 has such... Figure 13 The configuration shown (i.e., with a reduced outer diameter that does not extend to the annular frame 18) allows this method to be used.

[0234] Further possible modifications to the third embodiment of the method of the present invention are as follows: Figure 16 and Figure 17 The diagram is shown in the middle. Specifically, after the first protective film 22 is attached to the wafer W (see Figure 1). Figure 10 The first protective film 22 can be cut so that the outer diameter of the first protective film 22 is approximately the same as the outer diameter of the wafer W (see...). Figure 16 Subsequently, optionally, the back side 4 of the wafer W can be ground, for example, using a conventional grinding apparatus (not shown), to adjust the wafer thickness. After the grinding step, optionally, the back side 4 of the wafer can be polished (e.g., dry polishing) and / or etched (e.g., plasma etching).

[0235] Then, the second protective film 14 is attached to the back side 4 of the ground, and optionally polished and / or etched wafer W. The result of this attachment step (which can be performed in the same manner as described above) is as follows: Figure 17 As shown in this following figure, after the second protective film 14 is attached to the wafer W, a laser beam LB is applied to the wafer W from the rear side 4 of the wafer W at multiple locations along the cleaving line 12 to form multiple modified regions (not shown) in the wafer W along the cleaving line 12.

[0236] After the modified region has been formed in wafer W, the first protective film 22 is removed from the front side 2 of wafer W. Subsequently, wafer W is diced into individual dies 32 by radially expanding the second protective film 14. For example, the resulting dies 32 can be picked up directly from the second protective film 14 using a conventional pick-up device (not shown). The steps of applying a laser beam LB to wafer W, removing the first protective film 22 from wafer W, and dicing wafer W into individual dies 32 can be performed in the same manner as the method of the third embodiment described in detail above.

Claims

1. A method for processing a substrate (W), said substrate having a device region (6) with a plurality of devices (8) on one side (2), wherein, The method includes: Provide a first protective film (22); Provide a second protective film (14); The first protective film (22) is attached to one side (2) of the substrate (W) such that at least the central region of the front surface (24) of the first protective film (22) is in direct contact with one side (2) of the substrate (W); After attaching the first protective film (22) to one side (2) of the substrate (W), the substrate having the first protective film (22) attached thereto is placed on the support. The second protective film (14) is attached to the side (4) of the substrate (W) opposite to one side (2); and After attaching the second protective film (14) to the side (4) of the substrate (W) opposite to the side (2), a laser beam (LB) is applied from the side (4) of the substrate (W) opposite to the side (2) to the substrate (W), wherein The substrate (W) is made of a material that is transparent to the laser beam (LB). The second protective film (14) is made of a material that is transparent to the laser beam (LB), and The laser beam (LB) is applied to the substrate (W) at multiple locations to form multiple modified regions in the substrate (W).

2. The method according to claim 1, wherein, Attaching the first protective film (22) to one side (2) of the substrate (W) includes: The first protective film (22) is applied to one side (2) of the substrate (W) such that at least the central region of the front surface (24) of the first protective film (22) is in direct contact with one side (2) of the substrate (W); and During and / or after the first protective film (22) is applied to one side (2) of the substrate (W), an external stimulus is applied to the first protective film (22) such that the first protective film (22) is attached to one side (2) of the substrate (W).

3. The method according to claim 2, wherein, Applying the external stimulus to the first protective film (22) includes applying pressure to the first protective film (22), and / or heating the first protective film (22), and / or cooling the first protective film (22), and / or applying a vacuum to the first protective film (22), and / or irradiating the first protective film (22) with light.

4. The method according to any one of claims 1 to 3, wherein At least one dividing line (12) is formed on one side (2) of the substrate (W), and The laser beam (LB) is applied to the substrate (W) at multiple locations along the at least one dividing line (12) to form a plurality of modified regions in the substrate (W) along the at least one dividing line (12).

5. The method according to any one of claims 1 to 3, further comprising: The first protective film (22) is attached to the second protective film (14) so ​​as to encapsulate the substrate (W) between the first protective film (22) and the second protective film (14).

6. The method according to any one of claims 1 to 3, wherein, The second protective film (14) is attached to the side (4) of the substrate (W) opposite to the side (2) such that at least the central region of the front surface (20) of the second protective film (14) is in direct contact with the side (4) of the substrate (W) opposite to the side (2).

7. The method according to any one of claims 1 to 3, wherein The first protective film (22) is provided with an adhesive layer (26). The adhesive layer (26) is disposed only in the outer peripheral region of the front surface (24) of the first protective film (22), the outer peripheral region surrounding the central region of the front surface (24) of the first protective film (22), and The first protective film (22) is attached to one side (2) of the substrate (W) such that the adhesive layer (26) contacts only the outer peripheral portion of the one side (2) of the substrate (W).

8. The method according to any one of claims 1 to 3, wherein, The buffer layer is attached to the rear surface (28) of the first protective film (22), which is opposite to the front surface (24) of the first protective film.

9. The method according to claim 8, wherein, The substrate is attached to the rear surface of the buffer layer.

10. The method according to any one of claims 1 to 3, wherein The second protective film (14) is expandable, and The method further includes, after applying the laser beam (LB) to the substrate (W) from the side (4) opposite to the side (2) of the substrate (W), radially expanding the second protective film (14) to separate the devices (8) from each other.

11. The method according to any one of claims 1 to 3, wherein, The first protective film (22) is expandable, and The method further includes, after applying the laser beam (LB) to the substrate (W) from the side (4) opposite to the side (2) of the substrate (W), radially expanding the first protective film (22) to separate the devices (8) from each other.

12. The method according to any one of claims 1 to 3, further comprising: The first protective film (22) and / or the second protective film (14) are attached to the annular frame (18).

13. The method according to any one of claims 1 to 3, further comprising: Remove the first protective film (22) from one side (2) of the substrate (W).

Images