Chip manufacturing method

Abstract

To provide a chip manufacturing method capable of improving bending strength while suppressing variations in bending strength.SOLUTION: A chip manufacturing method includes a first step of forming a modified region 12 in an object 11 along a line A by irradiating the object 11 with laser light L along the line A, a second step of forming a chip 50 from the object 11 by cutting the object 11 along the line A using the modified region 12 after the first step, and a third step of applying stress F to the chip 50 along the Z direction after the second step.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a chip manufacturing method. [Background technology]

[0002] Patent Document 1 describes a method for processing the edge of a sheet glass. In this method, first, a plurality of raw sheet glass pieces are stacked and integrated with an adhesive to form a raw glass block. Next, the raw glass block is integrally fixed to a receiving stand, and is divided vertically and horizontally along the dividing lines by a disk cutter to form a large number of rectangular divided glass blocks. Next, a rotary polishing machine having a flat polishing surface on the upper surface of the disk body is rotated, and each end face of the divided glass block is polished by sliding it against the polishing surface of the rotary polishing machine while supplying an abrasive to the polishing surface. This results in a first-polished divided glass block. Then, the first-polished divided glass blocks are stacked in a plurality of stages, and each end face of these is polished with a rotating brush. After that, each divided sheet glass is placed in a container filled with warm water, and the adhesive is peeled off to obtain a sheet glass product. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5363190 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method described in Patent Document 1, the end faces of the glass plate are polished to improve the bending strength of the glass plate. However, according to the knowledge of the present inventors, when a disk cutter is used to manufacture chips such as plate glass as in Patent Document 1, the bending strength is lower and the variation in bending strength is larger than when chips are manufactured by cutting starting from a modified region formed by irradiation with laser light, for example.

[0005] An object of the present invention is to provide a chip manufacturing method capable of improving flexural strength while suppressing variations in flexural strength. [Means for solving the problem]

[0006] The chip manufacturing method of the present invention includes a first step of irradiating an object including a first surface and a second surface opposite the first surface with laser light along a line set along the first surface and the second surface to form a modified region in the object along the line, a second step after the first step of forming a chip from the object by cutting the object along the line using the modified region, and a third step after the second step of applying stress to the chip along a direction intersecting the first surface and the second surface.

[0007] In addition, the chip manufacturing method of the present invention includes a first step of irradiating an object including a first surface and a second surface opposite the first surface with laser light along a line set along the first surface and the second surface, thereby forming a modified region in the object along the line, and a second step of forming a chip from the object by cutting the object along the line using the modified region after the first step, and applying stress to the chip along a direction intersecting the first surface and the second surface.

[0008] In these manufacturing methods, a laser beam is irradiated onto an object to form modified regions in the object, which are then used to cut the object into chips. At the same time, stress is applied to the chips. According to the inventor's findings, applying stress to the chips in this manner can improve the flexural strength while suppressing variations in the flexural strength.

[0009] In the chip manufacturing method according to the present invention, stress may be applied to the chip multiple times in the third step, which makes it possible to more reliably improve the flexural strength.

[0010] In the chip manufacturing method according to the present invention, in the third step, the state in which the stress is applied to the chip may be maintained for a predetermined period of time, whereby the flexural strength can be improved more reliably.

[0011] In the chip manufacturing method according to the present invention, a plurality of lines may be set on the object, and in a first step, the laser light is irradiated along each of the plurality of lines to form modified regions in the object along each of the plurality of lines, in a second step, the object is cut along each of the plurality of lines to form a plurality of chips from the object, and in a third step, stress may be applied to the plurality of chips at the same time. In this case, a plurality of chips with improved flexural strength can be manufactured at the same time.

[0012] In the chip manufacturing method according to the present invention, the stress may be 80% or more of the average breaking strength of the chip, 90% or more of the average breaking strength of the chip, or even greater than the average breaking strength of the chip. In these cases, the flexural strength can be improved more reliably. Effect of the Invention

[0013] According to the present invention, it is possible to provide a chip manufacturing method capable of improving the flexural strength while suppressing variations in the flexural strength. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a laser processing device according to one embodiment. [Diagram 2] FIG. 2 is a plan view showing the stage in a state in which an object is supported. [Diagram 3] FIG. 3 is a schematic diagram showing the configuration of the laser irradiation unit shown in FIG. [Figure 4] FIG. 4 is a diagram for explaining one step of the chip manufacturing method. [Diagram 5] FIG. 5 is a diagram for explaining one step of the chip manufacturing method. [Figure 6] FIG. 6 is a diagram for explaining one step of the chip manufacturing method. [Figure 7] FIG. 7 is a diagram for explaining another example of a step of the chip manufacturing method. [Figure 8] FIG. 8 is a photograph showing the cross sections of various chips. [Figure 9] FIG. 9 is a graph showing the flexural strength of each chip shown in FIG. [Figure 10] FIG. 10 is a graph for explaining the first finding obtained by the present inventors. [Figure 11] FIG. 11 is a graph illustrating a second finding obtained by the present inventors. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] An embodiment will be described below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations may be omitted. In addition, each drawing may show an orthogonal coordinate system defined by an X-axis, a Y-axis, and a Z-axis.

[0016] Fig. 1 is a schematic diagram showing the configuration of a laser processing apparatus according to one embodiment. As shown in Fig. 1, the laser processing apparatus 1 includes a stage 2, a laser irradiation unit 3, driving units 4 and 5, and a control unit 6. The laser processing apparatus 1 is for forming a modified region 12 in the object 11 by irradiating the object 11 with laser light L. In addition, the laser processing apparatus 1 is also a chip manufacturing apparatus for manufacturing chips from the object 11 by cutting the object 11 using the modified region 12 or the like.

[0017] Fig. 2 is a plan view showing the stage in a state where an object is supported. Fig. 2 shows an imaginary line A indicating the schedule for laser processing. As shown in Figs. 1 and 2, the stage 2 has a film 21 to which the object 11 is attached, and a frame 22 that holds the outer edge of the film 21. That is, the stage 2 is for supporting the object 11 by holding the film 21 to which the object 11 is attached.

[0018] The stage 2 further has a pressing member 23 for expanding the film 21 by pushing up the film 21 from the opposite side to the object 11 (in the Z direction described below). The stage 2 is rotatable about an axis parallel to the Z direction. The stage 2 may be movable along both the X direction and the Y direction. The X direction and the Y direction are a first horizontal direction and a second horizontal direction that intersect (are perpendicular to) each other, and the Z direction is a vertical direction.

[0019] The laser irradiation unit 3 focuses laser light L, which is transparent to the object 11, and irradiates the object 11. When the laser light L is focused inside the object 11 supported by the stage 2, the laser light L is particularly absorbed in a portion corresponding to a focusing point C of the laser light L, and a modified region 12 is formed inside the object 11.

[0020] The modified region 12 is a region that differs from the surrounding non-modified region in terms of density, refractive index, mechanical strength, and other physical properties. Examples of the modified region 12 include a melting treatment region, a crack region, a dielectric breakdown region, and a refractive index change region. The modified region 12 can be formed such that a crack extends from the modified region 12 to the incident side of the laser light L and to the opposite side. Such modified region 12 and cracks are used, for example, to cut the object 11.

[0021] FIG. 3 is a schematic diagram showing the configuration of the laser irradiation unit shown in FIG. 1. FIG. 3 shows a virtual line A indicating the planned laser processing. As shown in FIG. 3, the laser irradiation unit 3 has a light source 31, a spatial light modulator 7, and a condenser lens 33. The light source 31 outputs the laser light L, for example, by a pulse oscillation method. Note that the laser irradiation unit 3 may be configured not to have the light source 31, and to introduce the laser light L from outside the laser irradiation unit 3. The spatial light modulator 7 modulates the laser light L output from the light source 31. The condenser lens 33 condenses the laser light L modulated by the spatial light modulator 7 and output from the spatial light modulator 7 toward the object 11.

[0022] As an example, when the stage 2 is moved along the X direction and the focal point C is moved along the X direction relative to the object 11, multiple modified spots 12s are formed in a row along the X direction. One modified spot 12s is formed by irradiating one pulse of laser light L. One row of modified regions 12 is a collection of multiple modified spots 12s lined up in a row. Adjacent modified spots 12s may be connected to each other or separated from each other depending on the relative moving speed of the focal point C with respect to the object 11 and the repetition frequency of the laser light L.

[0023] As shown in FIG. 1, the driving unit 4 includes a first moving unit 41 that moves the stage 2 in one direction in a plane intersecting (orthogonal) with the Z direction, and a second moving unit 42 that moves the stage 2 in another direction in a plane intersecting (orthogonal) with the Z direction. As an example, the first moving unit 41 moves the stage 2 along the X direction, and the second moving unit 42 moves the stage 2 along the Y direction. The driving unit 4 also rotates the stage 2 around an axis parallel to the Z direction as a rotation axis. The driving unit 5 supports the laser irradiation unit 3. The driving unit 5 moves the laser irradiation unit 3 along the X direction, the Y direction, and the Z direction. When the stage 2 and / or the laser irradiation unit 3 are moved in a state in which the focal point C of the laser light L is formed, the focal point C is moved relative to the object 11. That is, the driving units 4 and 5 are moving units that move at least one of the stage 2 and the laser irradiation unit 3 so that the focal point C of the laser light L moves relative to the object 11.

[0024] The control unit 6 controls the operations of the stage 2, the laser irradiation unit 3, and the driving units 4 and 5. The control unit 6 has a processing unit, a memory unit, and an input receiving unit (not shown). The processing unit is configured as a computer device including a processor, memory, storage, a communication device, etc. In the processing unit, the processor executes software (programs) loaded into the memory, etc., and controls reading and writing of data in the memory and storage, as well as communication by the communication device. The memory unit is, for example, a hard disk, and stores various data. The input receiving unit is an interface unit that displays various information and receives input of various information from the user. The input receiving unit constitutes a GUI (Graphical User Interface).

[0025] Next, a chip manufacturing method using the above-mentioned laser processing device 1 and the like will be described. In this manufacturing method, first, as shown in Figs. 2 and 3, the object 11 is supported on the stage 2. The object 11 includes a first surface 11a and a second surface 11b opposite to the first surface 11a. The object 11 is supported on the stage 2 by holding (contacting) the second surface 11b on the film 21 so that the first surface 11a faces the condenser lens 33 side. The object 11 is, for example, a glass wafer or a semiconductor wafer. Here, as an example, the object 11 is a silicon wafer. The silicon wafer here may be one on which a semiconductor device is formed, or may be a bare wafer. As an example, a line A is set on the object 11 in a two-dimensional lattice shape along the first surface 11a and the second surface 11b.

[0026] Subsequently, the first step is carried out. That is, here, the control unit 6 controls the laser irradiation unit 3 and the driving units 4 and 5, so that the focal point C of the laser light L is positioned inside the object 11 and the focal point C is relatively moved along one line A. As a result, the laser light is irradiated along the line A, and a modified region 12 and a crack extending from the modified region 12 are formed in the object 11 along the line A. In the first step, the laser light L is irradiated along each of the multiple lines A, so that the modified region 12 is formed in the object 11 along each of the multiple lines A.

[0027] Subsequently, the second step is carried out. That is, as shown in (a) and (b) of FIG. 4, the control unit 6 uses the pressing member 23 to push the film 21 up in the Z direction from the side opposite the object 11, i.e., from the second surface 11b side, thereby expanding the film 21. As a result, stress is applied to the object 11 in the direction in which the crack extending from the modified region 12 opens, and the crack advances. As a result, the object 11 is cut along the line A, and a plurality of chips 50 are formed from the object 11 at once. That is, in this second step, the chips 50 are formed from the object 11 by cutting the object 11 along the line A using the modified region 12 (and the crack extending from the modified region 12).

[0028] Subsequently, the third step is performed. In the third step, stress is applied to each of the chips 50 formed in the second step. For this purpose, a jig 100 for applying stress is prepared as shown in FIG. 5 and FIG. 6. The jig 100 includes a plurality of rod-shaped first members 101 extending along a first direction as viewed from the Z direction, and a plurality of rod-shaped second members 102 extending along a second direction intersecting (perpendicular to) the first direction as viewed from the Z direction. In the jig 100, the first members 101 and the second members 102 are combined in a lattice shape. Focusing on one chip 50, the first member 101 is arranged so as to pass through the center of the chip 50 and extend in the Y direction across the outer edge 50e of the chip 50 in the Y direction, and the second member 102 is arranged so as to pass through the center of the chip and extend in the X direction across the outer edge 50f of the chip 50 in the X direction. The jig 100 is held in contact with, for example, the first surface 50a (which is a part of the first surface 11a) of each chip 50.

[0029] In this state, the control unit 6 uses the pressing member 23 to push up the object 11, i.e., the chips 50, together with the film 21, in the Z direction from the second surface 50b side (which is a part of the second surface 11b). This causes stress F to be applied from the jig 100 to the multiple chips 50 collectively along the Z direction intersecting the first surface 11a (the first surface 50a of the chips 50) and the second surface 11b (the second surface 50b of the chips 50). Here, the control unit 6 repeats this process, thereby being able to apply stress F to the chips 50 multiple times. Alternatively, the control unit 6 can maintain the state in which stress F is applied to the chips 50 for a predetermined time.

[0030] The stress F can be 80% or more of the average breaking strength of the chip 50. For example, when the average value of the breaking strength (average breaking strength) in the simple bending test of the chip 50 is 363 MPa, the stress F can be about 290 MPa or more. Alternatively, the stress F is 90% or more of the average breaking strength of the chip 50. In this case, when the average breaking strength of the chip 50 is 363 MPa, the stress F can be about 326 MPa or more. Furthermore, the stress F may be a value larger than the average breaking strength. Note that, as an example, the stress F being 80% or more of the average breaking strength means that when the bending strength of the chip 50 is calculated based on the stress F, the calculated bending strength is 80% or more of the average breaking strength of the chip 50. Similarly, as an example, the stress F being about 290 MPa means that when the bending strength of the chip 50 is calculated based on the stress F, the calculated bending strength is about 290 MPa.

[0031] Here, the stress F is applied to the chip 50 using the stage 2 and the jig 100, but as shown in FIG. 7, the chip 50 may be transferred after the second step and a normal stress application device (e.g., a four-point bending test device) may be used to apply the stress F to the chip 50. Here, the chip 50 is placed on the support base 110, and then the stress F is applied to the chip 50 from the first surface 50a side by the stress application member 120. Again, the stress F may be applied to the chip 50 multiple times as shown in FIG. 7(a), or the state in which the stress F is applied to the chip 50 may be maintained for a predetermined time as shown in FIG. 7(b).

[0032] Next, the inventor's findings regarding the flexural strength of chips according to the cutting method and the treatment of the cut surface will be described. FIG. 8(a) shows a cut surface of a chip (hereinafter referred to as a "BD chip") formed by cutting with a blade (hereinafter referred to as "blade dicing"). FIG. 8(b) shows a cut surface of a chip (hereinafter referred to as an "SD chip") formed by cutting using a modified region as described above (hereinafter referred to as "stealth dicing"). FIG. 8(c) shows a cut surface of a chip (hereinafter referred to as an "SD etched chip") obtained by etching the cut surface of the SD chip. FIG. 8(d) shows a cut surface of a chip (hereinafter referred to as an "SD one-sided light-collecting chip") obtained by using cleavage while forming a modified region only on one side in the thickness direction. FIG. 8(e) shows a cut surface of a chip (hereinafter referred to as an "SD one-sided light-collecting etched chip") obtained by further etching the cut surface of the SD one-sided light-collecting chip.

[0033] FIG. 9 is a graph showing the flexural strength of each chip shown in FIG. 8. Point group A1 in FIG. 9 shows the flexural strength of the BD chip, point group A2 in FIG. 9 shows the flexural strength of the SD chip, point group A3 in FIG. 9 shows the flexural strength of the SD etched chip, point group A4 in FIG. 9 shows the flexural strength of the SD one-sided light-collecting chip, and point group A5 in FIG. 9 shows the flexural strength of the SD one-sided light-collecting etching chip. Comparing point group A1 and point group A2, it can be seen that the SD chip using stealth dicing has improved flexural strength and suppressed variation in flexural strength compared to the BD chip using blade dicing. Furthermore, for the chip using stealth dicing, etching (point group A3, A5) or cleavage (point group A4, A5) improves the flexural strength, but the variation in flexural strength also increases.

[0034] In response to this, the present inventor has found that it is possible to improve the flexural strength while suppressing the variation in the flexural strength by applying stress to the SD chip. FIG. 10 is a graph for explaining the first finding obtained by the present inventor. The point group B0 in FIG. 10 shows the flexural strength (static fracture stress) of a normal (stress-unloaded) SD chip. The average fracture strength of the SD chips belonging to the point group B0 is 363 MPa, the maximum fracture strength is 396 MPa, the minimum fracture strength is 318 MPa, and the Weibull coefficient is 19.3. Considering that the Weibull coefficient of the BD chip is about 3 to 4, the variation in the flexural strength is suppressed even for a normal SD chip.

[0035] In contrast, point group B1 shows the flexural strength when a stress F of 306 MPa, which is equivalent to about 84% of the average fracture strength of a normal SD chip, 363 MPa, is applied 10,000 times. Comparing point group B0 and point group B1, although there is little change in the maximum fracture strength, point group B1 is distributed at higher values ​​on average, and it can be seen that the variation in flexural strength has been suppressed and the average fracture strength has been improved.

[0036] Point groups C1, C2, and C3 show the flexural strength when a stress F of 357 MPa, which is equivalent to about 98% of the average fracture strength of a normal SD chip of 363 MPa, is applied 1000 times, 10000 times, and 100000 times, respectively. Comparing point group B0 with point groups C1, C2, and C3, it can be seen that, on average, from point group C1 to point group C3, the variation in flexural strength is suppressed while the center of the distribution is higher, and the average fracture strength is improved.

[0037] Point group D1, point group D2, point group D3, point group D4, and point group D5 show the flexural strength when a stress F of 382 MPa (i.e., a value greater than the average rupture strength), which corresponds to about 105% of the average rupture strength of 363 MPa for normal SD chips, is applied once, 10 times, 1000 times, 10000 times, and 100000 times, respectively. Comparing point group B0 and point group D1, it can be seen that when a relatively large stress F is applied, it is possible to improve the flexural strength while suppressing the variation in the flexural strength even by applying it once.

[0038] Furthermore, from point group D2 to point group D5, it can be seen that, on average, the variation in flexural strength is suppressed while the center of distribution is higher (compared to point group B0), and the average fracture strength is improved. In particular, in point group D4, the average fracture strength is 425Ma, the maximum fracture strength is 476MPa, the minimum fracture strength is 384MPa, and the Weibull coefficient is 19.2. In other words, when comparing point group B0 and point group D4, in a situation where there is little change in the Weibull coefficient, that is, in a situation where the variation is suppressed compared to the BD chip, the flexural strength is improved by about 117% compared to the normal SD chip.

[0039] 11 is a graph for explaining the second finding obtained by the present inventor. Point group E1, point group E2, point group E3, point group E4, point group E5, and point group E6 designate the flexural strength when a stress F of 357 MPa, which corresponds to about 98% of the average breaking strength of 363 MPa of a normal SD chip, is held for 1 hour, 5 hours, 1 day, 2 days, 3 days, and 19 days, respectively. Comparing point group B0 and point group E1, even if the time for holding the stress F is 1 hour, point group E1 is distributed at a high value on average, and it can be understood that the variation in flexural strength is suppressed and the average breaking strength is improved.

[0040] Furthermore, it can be seen that, on average, from point group E1 to point group E6, the center of distribution is higher (compared to point group B0) while the variation in the flexural strength is suppressed, and the average fracture strength is improved. In particular, for the entire point group E1 to point group E6, the average fracture strength is 418Ma, the maximum fracture strength is 499MPa, the minimum fracture strength is 376MPa, and the Weibull coefficient is 15.7. That is, in a situation where the change in the Weibull coefficient is small compared to, for example, a BD chip, that is, in a situation where the variation is suppressed compared to a BD chip, the flexural strength is improved by about 115% compared to a normal SD chip. In other words, it was found that if stress is applied to the SD chip by either method, the flexural strength can be improved by nearly 20% without significantly decreasing the Weibull coefficient.

[0041] Based on the above findings, the chip manufacturing method according to this embodiment provides the following effects. That is, in the chip manufacturing method according to this embodiment, the laser light L is irradiated onto the object 11 to form modified regions 12 in the object 11, and the modified regions 12 are used to cut the object 11 to form chips 50. At the same time, a stress F is applied to the chip 50. According to the above findings, by applying the stress F to the chip 50 in this manner, it is possible to improve the flexural strength while suppressing variations in the flexural strength.

[0042] Furthermore, in the chip manufacturing method according to this embodiment, in the third step, stress F may be applied to chip 50 multiple times. In this case, it is possible to improve the flexural strength more reliably. Alternatively, in the chip manufacturing method according to this embodiment, in the third step, the state in which stress F is applied to chip 50 may be maintained for a predetermined time. In this case, it is possible to improve the flexural strength more reliably.

[0043] In the chip manufacturing method according to this embodiment, a plurality of lines A are set on the object 11, and in a first step, a laser beam L is irradiated along each of the plurality of lines A to form modified regions 12 in the object 11 along each of the plurality of lines A. In a second step, the object 11 is cut along each of the plurality of lines A to form a plurality of chips 50 from the object 11. Then, in a third step, a stress F is applied to the plurality of chips 50 collectively. This makes it possible to collectively manufacture a plurality of chips 50 with improved flexural strength.

[0044] Furthermore, in the chip manufacturing method according to this embodiment, the stress F may be 80% or more (e.g., 84% or more) of the average breaking strength of the chip 50, or 90% or more (e.g., 98% or more) of the average breaking strength of the chip 50, or even a value (e.g., 105% or more) greater than the average breaking strength of the chip 50. In these cases, the flexural strength can be improved more reliably.

[0045] The above embodiment describes one aspect of the present invention, therefore, the present invention is not limited to the above embodiment and can be modified as desired.

[0046] For example, in the above embodiment, the case where the chip 50 is formed in the second step, and then the stress F is applied to the chip 50 in the third step in the laser processing device 1 or by transferring the chip 50 to another device has been described. However, the second step and the third step may be performed simultaneously. That is, in the chip manufacturing method, after the first step, the second step can be performed in which the chip 50 is formed from the object 11 and the stress F is applied to the chip 50 along the Z direction by cutting the object 11 along the line A using the modified region 12. In this case, as an example, when the film 21 is pushed up by the pressing member 23, the jig 100 may already be placed on the object 11. Alternatively, the stress caused by the pushing up of the pressing member 23 may be applied to the chip 50 without using the jig 100. [Explanation of symbols]

[0047] 1...laser processing device, 11...object, 11a...first surface, 11b...second surface, 50...chip, A...line, F...stress, L...laser light.

Claims

1. a first step of irradiating a laser beam along a line set along the first surface and the second surface of an object including a first surface and a second surface opposite to the first surface, thereby forming a modified region in the object along the line; a second step of forming a chip from the object by cutting the object along the line using the modified region after the first step; a third step of applying stress to the chip along a direction intersecting the first surface and the second surface after the second step; Equipped with In the third step, the stress is applied to the chip a plurality of times. Chip manufacturing method.

2. A first step of irradiating a laser beam along a line set along a first surface and a second surface opposite the first surface to an object, thereby forming a modified region in the object along the line; a second step of forming a chip from the object by cutting the object along the line using the modified region after the first step; a third step of applying stress to the chip along a direction intersecting the first surface and the second surface after the second step; Equipped with In the third step, the state in which the stress is applied to the chip is maintained. Chip manufacturing method.

3. A plurality of the lines are set on the object, In the first step, the laser light is irradiated along each of the plurality of lines to form the modified region in the object along each of the plurality of lines; In the second step, the object is cut along each of the lines to form a plurality of the chips from the object; In the third step, the stress is applied to the plurality of chips at once. The method for producing a chip according to claim 1 or 2.

4. A first step of irradiating a laser beam along a line set along the first surface and the second surface of an object including a first surface and a second surface opposite the first surface, thereby forming a modified region in the object along the line; a second step of forming a chip from the object by cutting the object along the line using the modified region after the first step; a third step of applying stress to the chip along a direction intersecting the first surface and the second surface after the second step; Equipped with The stress is equal to or greater than 80% of the average breaking strength of the chip. Chip manufacturing method.

5. The stress is 90% or more of the average breaking strength of the chip. The method for producing a chip according to any one of claims 1 to 4.

6. The stress is greater than the average breaking strength of the chip. The method for producing a chip according to any one of claims 1 to 5.

7. a first step of irradiating a laser beam along a line set along the first surface and the second surface of an object including a first surface and a second surface opposite to the first surface, thereby forming a modified region in the object along the line; a second step of forming a chip from the object by cutting the object along the line using the modified region after the first step, and applying stress to the chip along a direction intersecting the first surface and the second surface; Equipped with In the second step, the stress is applied to the chip a plurality of times. Chip manufacturing method.

8. A first step of forming a modified region in an object along a line set along the first surface and the second surface by irradiating a laser beam to the object, the second surface being opposite to the first surface; a second step of forming a chip from the object by cutting the object along the line using the modified region after the first step, and applying stress to the chip along a direction intersecting the first surface and the second surface; Equipped with In the second step, the state in which the stress is applied to the chip is maintained. Chip manufacturing method.

9. A first step of irradiating a laser beam along a line set along the first surface and the second surface of an object including a first surface and a second surface opposite the first surface, thereby forming a modified region in the object along the line; a second step of forming a chip from the object by cutting the object along the line using the modified region after the first step, and applying stress to the chip along a direction intersecting the first surface and the second surface; Equipped with The stress is equal to or greater than 80% of the average breaking strength of the chip. Chip manufacturing method.

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