PROCESSING METHOD OF A SUBSTRATE AND MANUFACTURING METHOD FOR CHIPS

Abstract

A processing method for a substrate (11), the method performing processing of the substrate (11) using a laser beam (LB) having a wavelength that transmits through a material forming the substrate (11) and that is focused in a region having a greater length along a thickness direction of the substrate (11) than a width along a direction perpendicular to the thickness direction, the method comprising: a shielding tunnel forming step (S1) of forming shielding tunnels (19), each of which has a fine pore opening in a front surface (11a) and / or a rear surface (11b) of the substrate (11) and an amorphous portion surrounding the fine pore (19a), by applying the laser beam (LB) to the substrate (11) so that at least a part of the region is positioned within the substrate (11); and a functional layer forming step (S2), after the shield tunnel forming step (S1), of forming a functional layer on the front surface (11a) of the substrate (11).

Description

TECHNICAL BACKGROUNDField of the invention

[0001] The present invention relates to a processing method of a substrate, the method performing processing of the substrate using a laser beam having a wavelength that transmits through the substrate and is focusable in a region having a longer length along a thickness direction of the substrate than a width along a direction perpendicular to the thickness direction, and also to a manufacturing method of chips, the method performing manufacturing of the chips from the substrate using the processing method. Description of related technology

[0002] Chips of semiconductor devices such as integrated circuits (ICs) or optical devices such as light-emitting diodes (LEDs) or laser diodes (LDs) are manufactured using a disc-shaped substrate made of a single-crystal material such as silicon, silicon carbide or sapphire.

[0003] In particular, such chips are formed by forming a functional layer comprising a conductive layer, a semiconductor layer and / or an insulating layer on a front surface of the substrate to form the devices, and then dividing the substrate along boundaries of the devices.

[0004] As a method for dividing a substrate, a method is known which uses a laser beam having a wavelength that transmits through a material constituting the substrate and is focusable in a region that is longer along a thickness direction of the substrate than a width along a direction perpendicular to the thickness direction (see, for example, JP 2014-168790A).

[0005] In this process, the laser beam is first applied to the substrate along the boundaries of the components, with the region where the beam is focused positioned within the substrate. As a result, shielding tunnels (filaments) are formed inside the substrate, each containing a fine pore and an amorphous portion surrounding the fine pore. In this process, the substrate is etched in such a way that the shielding tunnels are removed. As a result, chips are fabricated from the substrate.

[0006] Further information helpful for understanding the present invention can be found in the following documents: US 2014 / 0256150 A1 relates to a wafer processing method for forming a through hole in a wafer. US 2016 / 0023436 A1 relates to release layer compositions that enable the handling of a thin wafer during microelectronics manufacturing. PRESENTATION OF THE INVENTION

[0007] If a laser beam is applied from a front surface side of a substrate with a functional layer formed on the front surface, the propagation direction of the laser beam may change in the functional layer, which may cause a problem in that desired shielding tunnels are hardly formed in the substrate. On the other hand, if the laser beam is applied from a rear surface side of the substrate, a possible problem is that the functional layer may be damaged due to the laser beam reaching the front surface side of the substrate.

[0008] In view of these possible problems, the present invention has as an object to provide a processing method for a substrate with which desired shielding tunnels can be formed in the substrate without damaging a functional layer for a multi-device configuration, and a manufacturing method for chips with which the chips are manufactured from the substrate using the processing method.

[0009] According to a first aspect of the present invention, there is provided a processing method for a substrate, the method performing processing of the substrate using a laser beam having a wavelength that transmits through a material constituting the substrate and that is focused in a region having a length along a thickness direction of the substrate greater than a width along a direction perpendicular to the thickness direction.The method comprises: a shielding tunnel forming step of forming shielding tunnels, each of which has a fine pore opening in a front surface and / or a back surface of the substrate and an amorphous portion surrounding the fine pore, by applying the laser beam to the substrate so that at least a part of the region is positioned inside the substrate, and a functional layer forming step, after the shielding tunnel forming step, of forming a functional layer on the front surface of the substrate.

[0010] Preferably, the method may further comprise, between the shielding tunnel forming step and the functional layer forming step, an etching step of etching the shielding tunnels from the front surface and / or the back surface having the fine pore opening therein.

[0011] According to a second aspect of the present invention, there is provided a manufacturing method for chips, the method performing manufacturing the chips using a laser beam having a wavelength that transmits through a material forming the substrate and that is focused in a region having a greater length along a thickness direction of the substrate than a width along a direction perpendicular to the thickness direction.The method comprises: a shielding tunnel forming step of forming shielding tunnels, each having a fine pore opening in a front surface and / or a back surface of the substrate and an amorphous portion surrounding the fine pore, by applying the laser beam to the substrate so that at least a part of the region is positioned inside the substrate; an etching step, after the shielding tunnel forming step, of etching the shielding tunnels from the front surface and / or the back surface having the fine pore opening therein; a functional layer forming step, after the etching step, of forming a functional layer on the front surface of the substrate; and a dividing step, after the functional layer forming step, of dividing the substrate by applying an external force to the substrate.

[0012] In the present invention, the fine pore may preferably open only in the front surface or the back surface of the substrate.

[0013] In the present invention, before the functional layer forming step in which the functional layer is formed on the front surface of the substrate, the shielding tunnel forming step is performed to form the shielding tunnels each having the fine pore opening in the front surface and / or the back surface of the substrate and the amorphous portion surrounding the fine pore.

[0014] In other words, in the present invention, the shielding tunnels are formed in the substrate in a state where the functional layer is not formed on its front surface. Therefore, in the present invention, it is possible to form the shielding tunnels in the substrate as desired for the configuration of multiple devices without damaging the functional layer.

[0015] The above and other objects, features and advantages of the present invention and the modes for carrying them out will become more apparent and the invention itself will be best understood by studying the following description and the appended claims with reference to the attached drawings which show some preferred embodiments of the invention. SHORT DESCRIPTION OF THE FIGURES Fig. 1 is a perspective view schematically illustrating an example of a substrate used for manufacturing chips in the present invention; Fig. 2 is a flowchart schematically illustrating a processing method according to a first embodiment of a first aspect of the present invention for a substrate, in which the substrate is processed using a laser beam; Fig. 3A is a partial cross-sectional side view schematically illustrating how a first example of a shielding tunnel forming step in the device shown in Fig. 2 processing procedures are carried out; Fig. Figure 3B is a perspective view schematically illustrating one of a plurality of shielding tunnels formed within the substrate in the first example of the device shown in Fig. 3A; Fig. 4A is a partial cross-sectional side view schematically illustrating how a functional layer forming step in the Fig. 2 processing procedures are carried out; Fig. Fig. 4B is a cross-sectional view schematically illustrating the substrate having a functional layer formed on a front surface thereof by the Fig. 4A; Fig. 5 is a partial side cross-sectional view schematically illustrating how a second example of the shield tunnel forming step is performed, the second example being different from the first example of the shield tunnel forming step shown in Fig. 3A, differs; Fig. 6 is a flowchart schematically illustrating a processing method according to a second embodiment of the first aspect of the present invention for the substrate; Fig. 7A is a partial cross-sectional side view schematically illustrating how an etching step in the Fig. 6 processing procedure is carried out; Fig. Figure 7B is a cross-sectional view schematically showing the substrate into which shielding tunnels are partially formed by the Fig. 7A; Fig. 8 is a flowchart schematically illustrating a chip manufacturing method according to a first embodiment of a second aspect of the present invention; Fig. 9A is a partial cross-sectional side view schematically illustrating how a division step in the Fig. 8, wherein a frame support base is raised; Fig. 9B is a partial cross-sectional side view schematically illustrating how a division step in the Fig. 8 is carried out, wherein a frame support base is lowered; and Fig. 10 is a flowchart schematically illustrating a manufacturing method according to a second embodiment of the second aspect of the present invention for the substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view schematically illustrating an example of a substrate used for manufacturing chips in the present invention. Fig. The substrate 11 shown in Figure 1 is a disk-shaped wafer having a circular front surface 11a and a circular rear surface 11b and made of a single-crystal material such as silicon or silicon carbide.

[0017] A plurality of intersecting scribe lines 13 are arranged in a grid pattern on the substrate 11. The substrate 11 is divided into a plurality of regions 15 by the scribe lines 13, and a functional layer is formed on the front surface 11a in each region 15 to form a component, as will be explained below.

[0018] The chips are manufactured by dividing the substrate along the respective scribe lines 13 in each region 15 where the functional layer is formed. Note that there are no restrictions on the material, shape, structure, size, and the like of the substrate 11. For example, the substrate 11 could be made of another single-crystal material such as sapphire.

[0019] Fig. Fig. 2 is a flowchart schematically illustrating a processing method according to a first embodiment of a first aspect of the present invention, in which the substrate 11 is processed using a laser beam. In the processing method of the first embodiment, shielding tunnels 19 are formed in the substrate 11, including fine pores 19a opening in the rear surface 11b of the substrate 11, and amorphous portions 19b surrounding the fine pores 19a, respectively (see Fig. 3A and Fig. 3B; shielding tunnel formation step S1).

[0020] Fig. 3A is a partial cross-sectional side view schematically illustrating how a first example of the shield tunnel forming step S1 is performed. Fig. 3A illustrates how the shielding tunnels 19 are formed within the substrate 11 in a laser processing machine 2.

[0021] The laser processing machine 2 includes a disc-shaped support table 4. The support table 4 has an upper surface (support surface) with, for example, a circular shape. The support table 4 further includes a disc-shaped porous plate (not shown) whose upper surface is exposed in the support surface.

[0022] Furthermore, the porous plate is connected to a suction source (not shown), such as an ejector, via a flow channel formed inside the holding table 4. When this suction source is activated, a suction force acts on a space near the holding surface of the holding table 4. This allows, for example, the substrate 11 placed on the holding surface to be held on the holding table 4.

[0023] The holding table 4 is also connected to a horizontal movement mechanism (not shown). This horizontal movement mechanism comprises, for example, a ball screw, a motor, or the like. When this horizontal movement mechanism is activated, the holding table 4 is moved along a horizontal direction.

[0024] A head 6 of a laser beam irradiation unit is arranged above the holding table 4. The laser beam irradiation unit also includes a laser oscillator (not shown). This laser oscillator uses, for example, Nd:YAG or the like as a laser medium.

[0025] The laser oscillator applies a pulsed laser beam LB with a wavelength that transmits through a material forming the substrate 11 (for example, a wavelength of 1,064 nm). This pulsed laser beam LB has, for example, a pulse width of 10 ps and a frequency of 50 kHz.

[0026] After the power of this laser beam LB has been adjusted in an attenuator (not shown) (for example, its average power has been reduced to 2 W), the laser beam LB is applied directly downward from the head 6 via an optical system (not shown) including a condenser lens 6a and the like arranged in the head 6.

[0027] Furthermore, the laser beam LB is subjected to an aberration (in particular, a longitudinal deviation) by the optical system, for example. This results in the laser beam LB being focused in a region R that is longer along its propagation direction (a thickness direction of the substrate 11) than a width along a direction perpendicular to the propagation direction.

[0028] The head 6 of the laser beam irradiation unit is connected to a vertical movement mechanism (not shown). This vertical movement mechanism includes, for example, a ball screw, a motor, or the like. When this vertical movement mechanism is activated, the head 6 is moved in a vertical direction.

[0029] When forming the shielding tunnels 19 inside the substrate 11 in the laser processing machine 2, the substrate 11, which has a protective tape 17 bonded to its front surface 11a, is first placed on the support table 4 so that the rear surface 11b faces upward. Note that the protective tape 17 is made of, for example, a plastic and has a disc-like shape having substantially the same diameter as the substrate 11.

[0030] Alternatively, no protective tape 17 could be bonded to the front surface 11a of the substrate 11 in the shielding tunnel formation step S1. In other words, the substrate 11 could be placed on the support table 4 such that the front surface 11a comes into direct contact with the support surface of the support table 4.

[0031] Next, the suction source connected to the porous plate exposed in the support surface of the support table 4 is activated. As a result, the substrate 11 is held on the support table 4. The support table 4 and / or the head 6 are then adjusted to a position such that one end of the desired scribe line 13 on the substrate 11 and the area where the laser beam LB is to be focused overlap.

[0032] While the laser beam LB is applied by the head 6, the holding table 4 is next moved along a direction in which the desired scoring line 13 runs (see Fig. 3A). As a result, the shielding tunnels 19 are formed in an elongated region along the desired scribe line 13 on the substrate 11.

[0033] Fig. 3B is a perspective view schematically illustrating one of the shielding tunnels 19 formed inside the substrate 11. The shielding tunnel 19 has a fine pore 19a opening in both the front surface 11a and the back surface 11b of the substrate 11, and an amorphous portion 19b surrounding the fine pore 19a.

[0034] The above-mentioned processes are further repeated until the shielding tunnels 19 are formed in all elongated zones along the respective scribe lines 13. As a result, a substrate 11 is obtained in which the shielding tunnels 19 are formed in a lattice pattern in a plan view.

[0035] After the shield tunnel formation step S1, a functional layer is formed on the front surface 11a of the substrate 11 (functional layer formation step S2). In this functional layer formation step S2, a functional layer consisting of a single metal layer is formed on the front surface 11a of the substrate 11, for example, using physical vapor deposition (PVD). Note that this functional layer is used, for example, as electrodes for the back surface of power devices.

[0036] Fig. 4A is a partial cross-sectional side view schematically illustrating how the functional layer forming step S2 is performed. Fig. Figure 4A illustrates how the metal layer is formed on the front surface 11a of the substrate 11 in a sputtering system 8. It should be noted that in Fig. 4A some of the components of the sputtering system 8 are shown in blocks.

[0037] The sputtering system 8 includes a housing 10 defining a chamber C. A through-hole is formed in a bottom wall of the housing 10, and a support member 12 is arranged extending through the through-hole. The support member 12 supports a holding table 14 with an electrostatic chuck arranged on one side of an upper surface of the table.

[0038] A target 16 made of a metallic material is arranged above the holding table 14, and the target 16 is attached to an electrode 18. An excitation element 20 is arranged in the vicinity of the target 16 to excite the target 16. The target 16 is connected to a radiofrequency power supply 22 via the electrode 18.

[0039] A gas inlet 10a and a gas outlet 10b are formed in the left and right side walls of the housing 10, respectively. The gas inlet 10a can be connected to a sputtering gas supply source (e.g., argon or the like) via a valve (not shown) or the like, while the gas outlet 10b can be connected to a suction source for depressurizing the chamber C.

[0040] When forming the metal layer on the front surface 11a of the substrate 11 in the sputtering system 8, the protective tape 17 bonded to the front surface 11a of the substrate 11 is first removed, and a protective tape 21 similar to the protective tape 17 is bonded to the rear surface 11b.

[0041] Next, the substrate 11 is placed on the holding table 14 with the protective tape 21 interposed therebetween so that the exposed front surface 11a faces upward. Then, the electrostatic chuck disposed on the upper surface side of the holding table 14 is activated. As a result, the substrate 11 is held on the holding table 14.

[0042] Then, the suction source connected to the gas outlet 10b is activated to evacuate the chamber C, and the chamber C is depressurized until its internal pressure reaches 10 -2 up to 10 -4Pa decreases. The high-frequency power supply 22 is then activated so that high-frequency energy, for example, of 40 kHz, is applied via the electrode 18 to the target 16 excited by the excitation element 20, and at the same time, the sputtering gas is supplied from the supply source into the chamber C via the valve or the like, the gas inlet 10a, and the like.

[0043] As a result, a plasma containing ions of the sputtering gas is generated in the chamber C, and these ions impact the target 16. Metal particles sputtered from the target 16 by the impact of the ions of the sputtering gas then deposit on the front surface 11a of the substrate 11 and form the metal layer.

[0044] Fig. 4B is a cross-sectional view schematically illustrating the substrate 11 with a functional layer 23 formed of the single metal layer on the front surface 11a. Note that the functional layer 23 may also be formed with multiple thin layers. Specifically, the functional layer 23 formed with multiple thin layers is formed by repeatedly forming a thin layer using PVD, chemical vapor deposition (CVD), or the like, and patterning the thin layer by photolithography, etching, and the like.

[0045] In the Fig. 2, the shielding tunnel forming step S1 is performed before the functional layer forming step S2 in which the functional layer 23 is to be formed on the front surface 11a of the substrate 11 to form the shielding tunnels 19, each of which has the fine pore 19a opening in both the front surface 11a and the back surface 11b of the substrate 11, and the amorphous portion 19b surrounding the fine pore 19a.

[0046] In other words, the shielding tunnels 19 are formed in the substrate 11 without the functional layer 23 being formed on its front surface 11a. With this method, it is therefore possible to form the shielding tunnels 19 in the substrate 11 as desired without damaging the functional layer 23 for a multi-device configuration.

[0047] It should be noted that the above-mentioned details are those relating to the first embodiment of the first aspect of the present invention, and therefore, the present invention is not limited to the above-mentioned details. For example, in the shield tunnel forming step S1 of the processing method of the first embodiment, the shield tunnels 19 formed through the substrate 11 in its thickness direction may not be required, as long as the substrate 11 can be divided in a dividing step mentioned later herein, or the like.

[0048] Fig. 5 is a partial side cross-sectional view schematically illustrating how a second example of the shielding tunnel forming step S1 is performed, the second example being different from the first example of the shielding tunnel forming step S1 as shown in Fig. 3A. The Fig. The second example of the shielding tunnel formation step S1 shown in Figure 5 is similar to that shown in Fig. 3A is performed, although the shield tunnels 19 are formed so as not to pass through a substrate 11.

[0049] Specifically, these shielding tunnels 19 have fine pores 19a that open only in a rear surface 11b of the substrate 11, as well as amorphous sections 19b surrounding the fine pores 19a. Alternatively, these shielding tunnels 19 could have fine pores 19a that open only in a front surface 11a of the substrate 11, and amorphous sections 19b surrounding the fine pores 19a.

[0050] Furthermore, the construction of a laser processing machine for use in the shielding tunnel forming step S1 of the processing method is not limited to the construction of the above-mentioned laser processing machine 2. For example, the shielding tunnel forming step S1 may be performed using a laser processing machine provided with a vertical movement mechanism for moving the support table 4 in the vertical direction and a horizontal movement mechanism for moving the head 6 of a laser beam irradiation unit in the horizontal direction.

[0051] Alternatively, the shielding tunnel forming step S1 of the machining method could also be performed using a laser machining machine in which an optical scanning system capable of changing the direction of a laser beam LB emitted from the head 6 is arranged in the laser beam irradiation unit. Note that this optical scanning system includes, for example, a galvano scanner, an acoustic optical device (AOD), a polygon mirror, and / or the like.

[0052] Therefore, in the shield tunnel forming step S1 of the machining process, it is only required that the substrate 11 held on the holding table 4 and the area where the laser beam LB applied from the head 6 is to be focused can be relatively moved along the horizontal direction and the vertical direction, respectively, and no design restrictions are provided for their relative movement.

[0053] In the processing method, the shielding tunnels 19 could be partially removed, for example by 65% ​​to 75%, before the functional layer formation step S2. Fig. 6 is a flowchart schematically illustrating a processing method according to a second embodiment of the first aspect of the present invention for the substrate in which the shielding tunnels 19 are partially removed.

[0054] In the Fig. 6, the shielding tunnels 19 are etched from the rear surface 11b of the substrate 11 between the shielding tunnel forming step S1 and the functional layer forming step S2 (etching step S3).

[0055] Fig. 7A is a partial cross-sectional side view schematically illustrating how the etching step S3 is performed in the processing method according to the second embodiment. In detail, Fig. 7A shows how the shielding tunnels 19 formed through the substrate 11 are partially etched, for example partially on one side of the rear surface 11b, with an etchant E in an etching system 24.

[0056] The etching system 24 has a holding table 26, similar to that shown in Fig. 3A. The holding table 26 also has a porous plate which is connected to a suction source (not shown) such as an ejector via a flow channel formed inside the holding table 26.

[0057] When this suction source is activated, a suction force acts on a space near a holding surface of the holding table 26. As a result, the substrate 11 placed on the holding surface can be held on the holding table 26.

[0058] The support table 26 is connected to a rotary drive mechanism (not shown). This rotary drive mechanism includes, for example, a spindle, a motor, and the like. Upon activation of this rotary drive mechanism, the support table 26 is rotated about a straight line as the rotation axis, which passes through the center of the support surface and extends along a vertical direction.

[0059] A nozzle 28 is arranged above the holding table 26, which supplies the etchant E to the substrate 11 held on the holding table 26. This etchant E contains, for example, hydrofluoric acid or the like.

[0060] When partially etching the shielding tunnels 19 with the etchant E in the etching system 24, the substrate 11, on whose front surface 11a a protective tape 17 is bonded, is first placed on the holding table 26 such that the rear surface 11b is directed upwards.

[0061] Alternatively, in etching step S3, no protective tape 17 could be bonded to the front surface 11a of the substrate 11. In other words, the substrate 11 could be placed on the support table 26 such that the front surface 11a comes into direct contact with the support surface of the support table 26.

[0062] Next, the suction source connected to the porous plate exposed in the support surface of the support table 26 is activated. As a result, the substrate 11 is held on the support table 26. While the etchant E is supplied to the rear surface 11b of the substrate 11, the rotation drive mechanism is then activated, so that the substrate 11 is driven for a predetermined period of time.

[0063] As a result, the shielding tunnels 19 are partially etched on the rear surface 11b. Fig. 7B is a cross-sectional view schematically illustrating the substrate 11 into which the shielding tunnels 19 have been partially etched.

[0064] On the rear surface 11b of the substrate 11, grooves 11c are formed by this etching in elongated zones along the scribe lines 13. It should be noted that in this etching, the substrate 11 could be etched in sections where the shielding tunnels 19 are not formed, ie, in sections that overlap the regions 15 (see Fig. 1).

[0065] In the etching step S3, the etching could be continued until the shielding tunnels 19 are completely removed, ie until the substrate 11 is divided along the scribe lines 13.

[0066] In etching step S3, the shielding tunnels 19 on the side of the front surface 11a could be partially removed. In other words, the shielding tunnels 19 could be etched in etching step S3, leaving them exposed from the front surface 11a by separating the protective tape 17.

[0067] The present invention also relates to a method for manufacturing chips comprising the above-mentioned substrate processing method. Fig. 8 is a flowchart schematically illustrating a manufacturing method according to a first embodiment of a second aspect of the present invention for chips. Fig. In the manufacturing process shown in Fig. 8, the above-mentioned shield tunnel forming step S1, the etching step S3 and the functional layer forming step S3 are carried out in this order.

[0068] After the functional layer forming step S2, the substrate 11 is then divided by applying an external force to the substrate 11 (dividing step S4). Fig. 9A and Fig. 9B are partial cross-sectional side views schematically illustrating how the dividing step S4 is performed while raising and lowering a frame support base 34a in the manufacturing method according to the first embodiment.

[0069] In the Fig. 9A and Fig. 9B shows how the substrate 11 and the functional layer 23 are divided along the scribe lines 13 on an expanding machine 30 by applying an external force to the substrate 11 and the functional layer 23, causing the substrate 11 and the functional layer 23 to expand along a radial direction.

[0070] Note that prior to the dividing step S4, the protective tape 21 is separated from the rear surface 11b of the substrate 11, and a disc-shaped dividing tape 25 having a larger diameter than the substrate 11 is rebonded to the rear surface 11b of the substrate 11 at a central portion thereof. Also bonded to an outer peripheral portion of the dividing tape 25 is an annular frame 27 in which a circular opening having a larger diameter than the substrate 11 is formed.

[0071] The expanding machine 30 includes a cylindrical drum 32. A support device 34 is arranged around the drum 32. The support device 34 includes a frame support base 34a arranged to surround an upper end portion of the drum 32.

[0072] On an upper surface of the frame support base 34a, a plurality of clamping portions 34b are arranged at substantially equal angular intervals along a circumferential direction of the frame support base 34a. When the substrate 11 connected to the frame 27 with the dividing band 25 interposed therebetween is loaded into the expanding machine 30, the frame 27 with the dividing band 25 interposed therebetween is placed on the frame support base 34a, and the frame 27 is clamped by the frame support base 34a and the clamping blocks 34b.

[0073] On a lower surface of the frame support base 34a, a plurality of rods 34c are arranged at substantially equal angular intervals along the circumferential direction of the frame support base 34a. The rods 34c are, for example, rods of air cylinders that are movable up and down. When the rods 34c are moved up and down, the base of the frame support base 34a and the portions 34b of the clamps are also moved up and down along the rods 34c.

[0074] When dividing the substrate 11 along the scribe lines 13 on the expanding machine 30, the rods 34c are first moved upward so that the upper surface of the frame support base 34a is positioned on the same plane as an upper end of the drum 32.

[0075] The substrate 11, which is connected to the frame 27 via the dividing band 25, is then loaded onto the expanding machine 30 such that the functional layer 23 is directed upwards and the frame 27 is clamped by the frame support base 34a and the clamping portions 34b (see Fig. 9A). Next, the base of the frame support base 34a and the sections with the clamps 34b are moved downward along the rods 34c.

[0076] As a result, the dividing band 25 is widened by a distance over which the upper end of the drum 32 and the frame support base 34a of the frame are separated from each other. At this time, an external force acts on the substrate 11 and also on the functional layer 23, causing them to expand. As a result, the substrate 11 and the functional layer 23 are divided along the scribe lines 13 (see Fig. 9B).

[0077] It should be noted that in the manufacturing process, the functional layer 23 could be divided along the scribe lines 13 before the dividing step S4. Fig. 10 is a flowchart schematically illustrating an example of such a method for manufacturing chips as a manufacturing method according to a second embodiment of the second aspect of the present invention.

[0078] In the manufacturing method according to the second embodiment, as shown in Fig. As shown in Figure 10, a functional layer 23 is patterned between the functional layer formation step S2 and the dividing step S4 such that the functional layer 23 is removed in regions where the functional layer 23 overlaps the shielding tunnels 19 (patterning step S5). This patterning step is performed, for example, using photolithography, etching, and so on.

Claims

[1] A processing method for a substrate (11), the method performing processing of the substrate (11) using a laser beam (LB) having a wavelength that transmits through a material constituting the substrate (11) and that is focused in a region having a greater length along a thickness direction of the substrate (11) than a width along a direction perpendicular to the thickness direction, the method comprising: a shielding tunnel forming step (S1) of forming shielding tunnels (19), each of which has a fine pore opening in a front surface (11a) and / or a rear surface (11b) of the substrate (11) and an amorphous portion surrounding the fine pore (19a), by applying the laser beam (LB) to the substrate (11) so that at least a part of the region is positioned within the substrate (11); and a functional layer forming step (S2), after the shield tunnel forming step (S1), of forming a functional layer on the front surface (11a) of the substrate (11). [2] The machining method according to claim 1, further comprising: between the shielding tunnel forming step (S1) and the functional layer forming step (S2), an etching step (S3) of etching the shielding tunnels (19) from the front surface (11a) and / or the back surface (11b) having the fine pore opening therein. [3] The machining method according to claim 1 or 2, wherein the fine pore (19a) opens only to the front surface (11a) or the back surface (11b) of the substrate (11). [4] A manufacturing method for chips, the method comprising manufacturing the chips using a laser beam (LB) having a wavelength that transmits through a material forming the substrate (11) and being focused in a region having a greater length along a thickness direction of the substrate (11) than a width along a direction perpendicular to the thickness direction, the method comprising: a shielding tunnel forming step (S1) of forming shielding tunnels (19), each having a fine pore opening in a front surface (11a) and / or a rear surface (11b) of the substrate (11) and an amorphous portion surrounding the fine pore (19a), by applying the laser beam (LB) to the substrate (11) so that at least a part of the region is positioned within the substrate (11); an etching step (S3), after the shielding tunnel forming step (S1), of etching the shielding tunnels (19) from the front surface (11a) and / or the back surface (11b) having the fine pore opening therein; a functional layer forming step (S2), after the etching step (S3), of forming a functional layer on the front surface (11a) of the substrate (11); and a dividing step (S4), after the functional layer forming step (S2), of dividing the substrate (11) by applying an external force to the substrate (11). [5] A manufacturing method according to claim 4, wherein the fine pore (19a) opens only in the front surface (11a) or the back surface (11b) of the substrate (11).

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