JP2011206838A - Laser beam machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strength and the quality of a workpiece after being machined.SOLUTION: By irradiating a workpiece 1 with laser beam, reformed areas 7 are formed along the profiles of hollowed portion Q1, Q2 of the workpiece 1, then the workpiece 1 is etched. Thus, the etching is selectively developed along a crack included in the reformed area 7 or extending from the reformed area 7, and the hollowed portions Q1, Q2 are separated and moved from the workpiece 1. In this case, the reformed areas 7 are formed so as to connected together along the profiles of the hollowed portions Q1, Q2, and exposed on a surface 3 side of the workpiece 1. In the present embodiment, the hollowed portions Q1, Q2 can be machined in a hollowing manner from the workpiece 1 without applying any external stress, and any crack formed as the reformed area 7 is formed can be removed by the etching.

Description

  The present invention relates to a laser processing method, and more particularly, to a laser processing method for processing so as to penetrate a predetermined portion of a processing object.

  As a conventional laser processing method, there is known a method of forming a modified region inside a processing target by irradiating a plate-shaped processing target with a laser beam with a focusing point (for example, Patent Document 1). In addition, by applying an external stress to a workpiece on which a modified region is formed using such a processing method, the workpiece can be divided into a plurality of chips starting from the modified region. (For example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 4-111800 JP 2004-343008 A

  Here, in recent years, in the laser processing method as described above, there is a case where processing is performed so as to penetrate a predetermined portion of the processing object using a modified region formed inside the processing object. However, in this case, a crack or breakage occurs in the workpiece, and the strength and quality of the workpiece after processing may be reduced.

  Then, this invention makes it a subject to provide the laser processing method which can improve the intensity | strength and quality in the processing target object after a process.

  In order to solve the above problems, a laser processing method according to the present invention uses a modified region formed by condensing a laser beam inside a processing object so as to pierce a predetermined portion of the processing object. A laser processing method for processing, wherein a laser beam is applied to a workpiece to form a modified region along the outer shape of a predetermined portion of the workpiece, and after the laser beam irradiation step , Etching the processing object to selectively advance the etching along a crack included in or extending from the modified region by performing an etching process, and a predetermined portion is processed after the etching processing step A separation movement step of moving away from the object, and in the laser light irradiation step, a modified region is formed so that a crack is connected along the outer shape, and on the outer surface side of the processing object Wherein the exposing the crack.

  In this laser processing method, since it is possible to process a predetermined portion so as to penetrate from the object to be processed without applying external stress, it is possible to suppress damage to the object to be processed or a decrease in strength due to the application of external stress. Furthermore, the crack which arises with formation of a modification area | region can be removed from the processed target object by an etching process process. Therefore, it is possible to improve the strength and quality of the processed object after processing.

  In the laser light irradiation step, the first modified region is formed at the first depth position in the laser light irradiation direction on the processing target, and then the laser light irradiation surface side of the processing target from the first depth position. It is preferable to form the second modified region at the second depth position. In this case, the influence of the existing first modified region can be prevented from reaching the formation of the second modified region, and the second modified region can be formed with high accuracy.

  Further, in the laser beam irradiation step, the step of irradiating the laser beam while relatively moving the laser beam condensing point along one direction orthogonal to the laser beam irradiating direction is the depth position of the condensing point in the irradiation direction. It is preferable to include a first step that is repeatedly performed by changing the first step, and a second step that is repeatedly performed by changing the position of the condensing point in the irradiation direction and the other direction orthogonal to the one direction. In this case, the tact time of the laser beam irradiation process can be shortened.

  Moreover, it is preferable that the external shape of a predetermined part has a taper part which inclines with respect to the orthogonal direction of this one surface so that it may spread as it goes to the one surface side of a workpiece. In this case, in the separation movement step, for example, the predetermined portion can be easily moved away from the workpiece by moving the predetermined portion so as to be extracted from the one surface side.

  According to the present invention, it is possible to improve the strength and quality of a processed object after processing.

It is a schematic block diagram of the laser processing apparatus used for formation of a modification area | region. It is a top view of the processing target object used as the object of formation of a modification field. It is sectional drawing along the III-III line of the workpiece of FIG. It is a top view of the processing target after laser processing. It is sectional drawing along the VV line of the workpiece of FIG. It is sectional drawing along the VI-VI line of the processing target object of FIG. It is a chart which shows an example of an etching agent. (A) is a top view which shows a process target object, (b) is a side view which shows the process target object of Fig.8 (a). (A) is a side view showing a laser processing method according to the first embodiment, (b) is a side view showing a continuation of FIG. 9 (a), and (c) is a side view showing a continuation of FIG. 9 (b). is there. (A) is a top view which shows the continuation of FIG.9 (c), (b) is a side view which shows the processing target object of Fig.10 (a). (A) is a top view which shows the continuation of FIG. 10, (b) is a side view which shows the processing target object of Fig.11 (a). (A) is a side view showing a continuation of FIG. 11, (b) is a side view showing a continuation of FIG. 12 (a), and (c) is a side view showing a continuation of FIG. 12 (b). (A) is a top view which shows the continuation of FIG.12 (c), (b) is a side view which shows the process target object of Fig.13 (a). (A) is a side view showing a modification of the first embodiment, (b) is a side view showing another modification of the first embodiment, and (c) shows still another modification of the first embodiment. It is a side view. (A) is a side view which shows another modification of 1st Embodiment, (b) is a side view which shows the continuation of Fig.15 (a). It is a side view which shows another modification of 1st Embodiment. (A) is a side view showing a laser processing method according to the second embodiment, (b) is a side view showing a continuation of FIG. 17 (a), and (c) is a side view showing a continuation of FIG. 17 (b). is there. It is a side view which shows the continuation of FIG.17 (c). It is a side view which shows the modification of 2nd Embodiment. (A) is a side view showing a laser processing method according to the third embodiment, (b) is a side view showing a continuation of FIG. 20 (a), (c) is a side view showing a continuation of FIG. 20 (b), (D) is a side view showing a continuation of FIG. It is a side view which shows the continuation of FIG.20 (d). (A) is a side view which shows the modification of 3rd Embodiment, (b) is a side view which shows the other modification of 3rd Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  In the laser processing method according to the present embodiment, processing is performed so as to pierce a predetermined portion of the processing object using a modified region formed by condensing laser light inside the processing object. First, the formation of the modified region will be described below with reference to FIGS.

  As shown in FIG. 1, a laser processing apparatus 100 includes a laser light source 101 that oscillates a laser beam L, a dichroic mirror 103 that is arranged so as to change the direction of the optical axis (optical path) of the laser beam L, and A condensing lens 105 for condensing the laser light L. Further, the laser processing apparatus 100 includes a support base 107 for supporting the workpiece 1 irradiated with the laser light L condensed by the condensing lens 105, and a stage 111 for moving the support base 107. And a laser light source control unit 102 for controlling the laser light source 101 to adjust the output of the laser light L, the pulse width, and the like, and a stage control unit 115 for controlling the movement of the stage 111.

  In this laser processing apparatus 100, the laser beam L emitted from the laser light source 101 has its optical axis changed by 90 ° by the dichroic mirror 103, and is a plate-like processing object placed on the support base 107. 1 is condensed by the condensing lens 105. At the same time, the stage 111 is moved, and the workpiece 1 is moved relative to the laser beam L along the modified region formation scheduled portion 5. As a result, a modified region along the modified region formation scheduled portion 5 is formed on the workpiece 1.

  As the processing object 1, a semiconductor material, a piezoelectric material, or the like is used. As illustrated in FIG. 2, a modified region formation scheduled portion 5 is set in the processing object 1. The modified region formation scheduled portion 5 here is a virtual line extending linearly. When the modified region is formed inside the workpiece 1, as shown in FIG. 3, the laser beam L is applied to the modified region formation scheduled portion 5 in a state where the focusing point P is aligned with the inside of the workpiece 1. (Ie, in the direction of arrow A in FIG. 2). Thereby, as shown in FIGS. 4 to 6, the modified region 7 is formed inside the workpiece 1 along the modified region formation scheduled portion 5, and this modified region 7 is removed by etching described later. Region 8 is formed.

  In addition, the condensing point P is a location where the laser light L is condensed. Further, the modified region formation schedule is not limited to a straight line, but may be a curved line, a curved surface, a flat three-dimensional shape, or a coordinate designated. In addition, the modified region 7 may be formed continuously or intermittently. Further, the modified region 7 may be in the form of a line or a dot. In short, the modified region 7 only needs to be formed at least inside the workpiece 1. In addition, a crack may be formed starting from the modified region 7, and the crack and modified region 7 may be exposed on the outer surface (front surface, back surface, or outer peripheral surface) of the workpiece 1.

  Incidentally, here, the laser beam L passes through the workpiece 1 and is particularly absorbed in the vicinity of the condensing point inside the workpiece 1, whereby a modified region 7 is formed in the workpiece 1. (Ie, internal absorption laser processing). Therefore, since the laser beam L is hardly absorbed by the surface 3 of the workpiece 1, the surface 3 of the workpiece 1 is not melted. In general, when a removed portion such as a hole or a groove is formed by being melted and removed from the front surface 3 (surface absorption laser processing), the processing region gradually proceeds from the front surface 3 side to the back surface side.

  By the way, the modified region formed by the laser processing apparatus according to the present embodiment refers to a region where the density, refractive index, mechanical strength, and other physical characteristics are different from the surroundings. Examples of the modified region include a melt treatment region, a crack region, a dielectric breakdown region, a refractive index change region, and the like, and there is a region where these are mixed. Furthermore, as the modified region, there are a region where the density of the modified region in the material of the workpiece is changed compared to the density of the non-modified region, and a region where lattice defects are formed. Also known as the metastatic region).

In addition, the area where the density of the melt-processed area, the refractive index changing area, the modified area is changed compared to the density of the non-modified area, and the area where lattice defects are formed are further divided into these areas and the modified area. In some cases, cracks (cracks, microcracks) are included in the interface with the non-modified region. The cracks included may be formed over the entire surface of the modified region, or may be formed in only a part or a plurality of parts. Examples of the processing object 1 include those containing or consisting of silicon, glass, LiTaO ₃ or sapphire (Al ₂ O ₃ ).

  Here, in the present embodiment, after the modified region 7 is formed in the workpiece 1, a crack included in the modified region 7 or extending from the modified region 7 is performed by etching the workpiece 1. (Also referred to as a crack, a microcrack, a crack, etc., hereinafter simply referred to as “crack”), the etching is selectively advanced, and a region corresponding to the outer shape of a predetermined portion (piercing portion) in the workpiece 1 Remove.

  Specifically, in the etching process of the present embodiment, a capillary phenomenon or the like is used to infiltrate an etchant into a crack that is included in or extends from the modified region 7 of the workpiece 1 and the crack is generated. Etch progresses along the surface. Thereby, in the processing target object 1, etching progresses and is removed at a selective and high etching rate along the crack. At the same time, by utilizing the feature that the etching rate of the modified region 7 is high, etching is selectively advanced and removed along the modified region 7.

  As the etching process of this embodiment, there are a case where the workpiece is immersed in the etching agent (dipping method: Dipping) and a case where the etching agent is applied while rotating the workpiece (spin etching method: SpinEtching). is there.

  FIG. 7 is a chart showing an example of the etching agent used for each material of the substrate. The etching agent is used at a temperature from room temperature to around 100 ° C., and is set to an appropriate temperature according to a required etching rate or the like. For example, when Si (anisotropic) is etched with KOH, the temperature is preferably about 60 ° C. Further, the etching agent can be not only liquid but also gel (jelly or semi-solid).

[First Embodiment]
Next, the first embodiment of the present invention will be described in detail. FIG. 8 is a diagram showing a workpiece to be processed by the laser processing method of the present embodiment, and FIGS. 9 to 13 are flowcharts showing the laser processing method of the present embodiment.

  As shown in FIGS. 8 to 13, the present embodiment is a processing method for manufacturing a display plate or a protection plate stacked on a device substrate 31 (see FIG. 13), for example, and a device 32 (see FIG. 13) is exposed to the outside, the workpiece 1 is processed so as to pierce the plurality of pierced portions Q1, Q2. Here, the penetration parts Q1 and Q2 are formed in a columnar shape whose axial direction is the thickness direction of the workpiece 1, and the diameter of the penetration part Q2 is smaller than the diameter of the penetration part Q1. .

  In the following description, the thickness direction of the workpiece 1 (irradiation direction of the laser beam L) is the Z direction, and one direction along the surface 3 that is the laser beam irradiation surface of the workpiece 1 (laser beam). The direction orthogonal to the irradiation direction of L) is the X direction, and the other direction orthogonal to the X and Z directions (the irradiation direction of the laser light L and the direction orthogonal to one direction) is the Y direction.

  As shown in FIG. 8, the workpiece 1 is a plate-like member that is transparent to the wavelength of the laser beam L to be irradiated, and a rectangular plate-shaped glass substrate is used as the workpiece 1 of the present embodiment. It has been. Further, here, the modified region formation scheduled portion 5 whose coordinates are specified along the outer shape of the penetrating portions Q1 and Q2 is three-dimensionally provided on the workpiece 1.

  When processing the workpiece 1 in the present embodiment, first, as shown in FIG. 9A, the holding tape 16 is attached to the back surface 21 of the workpiece 1, and the surface 3 side of the workpiece 1 is attached. Place it on the mounting table upward.

  Subsequently, a condensing point of the laser beam L (hereinafter simply referred to as “condensing point”) is aligned with the Z-direction position on the back surface 21 side of the workpiece 1, and the condensing point is relatively moved in the X direction. At the same time, the laser beam L is irradiated on and off so that the modified region 7 is formed in the modified region formation scheduled portion 5 (see FIG. 8). Specifically, the laser beam L is irradiated (ON) at the outer positions of the portions Q1 and Q2 where the condensing point penetrates, and the laser beam L is not irradiated (OFF) at other positions.

  Thereby, in the Z direction position (first depth position) on the back surface 21 side of the workpiece 1, the modified region (first modified region) 7 exposed on the back surface 21 is intermittently formed along the X direction. Is done. In this case, since the pulsed laser beam is spot-irradiated as the laser beam L, the modified region 7 to be formed is composed of a modified spot. In the modified region 7, a crack generated from the modified region 7 is included (the same applies to the following modified regions).

  Subsequently, as shown in FIG. 9B, after the Z-direction position of the condensing point is moved and changed to the surface 3 side, the modified region formation scheduled portion 5 is moved while relatively moving the condensing point in the X direction. The laser beam L is irradiated ON / OFF so that the modified region 7 is formed. Thus, the reforming region (second reforming region) 7 is connected to the existing reforming region 7 at the Z-direction position (second depth position) on the surface 3 side of the existing reforming region 7. Is newly formed. In other words, the modified region 7 is newly formed, and the crack included in the modified region 7 and the crack included in the existing modified region 7 on the back surface 21 side are connected to each other.

  Subsequently, the above-described ON / OFF irradiation of the laser light L is repeatedly performed by changing the Z-direction position of the condensing point in the order from the back surface 21 side to the front surface 3 side (first step). As a result, as shown in FIG. 9C, the modified regions 7 extending in the Z direction and connected to each other in the workpiece 1 as viewed from the Y direction are along the outer shapes of the punched portions Q1 and Q2. It is formed.

  When the relative movement of the condensing point at the time of ON / OFF irradiation of the laser beam L is repeatedly performed in the order from the back surface 21 side to the front surface 3 side, the light beam is collected so as to reciprocate in the X direction in order to shorten the tact time. It is preferable to move the light spot relatively. In other words, after the laser beam L is turned ON / OFF while the focusing point is relatively moved in one direction in the X direction, the laser beam L is turned ON / OFF while the focusing point is relatively moved in the other direction in the X direction. It is preferable to do this.

  Subsequently, the steps shown in FIGS. 9A to 9C are repeatedly performed by changing the condensing point position of the laser light L in the Y direction (second step). As a result, the modified regions 7 that are connected to each other even on the same XY plane inside the workpiece 1 are formed along the outer shapes of the punched portions Q1 and Q2. That is, as shown in FIG. 10, the modified region 7 is connected along the side surfaces of the cylindrical penetrating portions Q <b> 1 and Q <b> 2, and is exposed on the front surface 3 and the back surface 21 side of the workpiece 1. Yes. The modified region 7 extends along the Z direction when viewed in the Y direction (X direction), and has a portion extending in a curved line or arc shape when viewed in the Z direction.

  Subsequently, as shown in FIG. 11, an etching process is performed on the workpiece 1 in which the modified region 7 is formed (etching process step). Specifically, the etching agent is infiltrated into the inside from the modified region 7 exposed on the front surface 3 and the back surface 21, and the etching is selectively progressed along the modified region 7 and the crack included in the modified region 7. The region corresponding to the outer shape of the punched portions Q1, Q2 in the workpiece 1 is removed.

  Subsequently, as shown in FIG. 12 (a), a remove tape 17 is attached to the surface 3 of the workpiece 1, and as shown in FIG. 12 (b), the remove tape 17 is lifted and moved. The piercing portions Q1, Q2 are removed (separated) from the workpiece 1 (separated movement process). Finally, the workpiece 1 is removed from the holding tape 16 as shown in FIG.

  By the above, it processes so that the penetration part Q1, Q2 of the workpiece 1 may be penetrated, and the through-hole 33 will be formed in the workpiece 1. FIG. Thereafter, as shown in FIG. 13, the processed object 1 ′ is laminated on the device substrate 31 such that the through hole 33 is positioned on the device 32 of the device substrate 31.

  As mentioned above, according to this embodiment, since it can process so that the penetration part Q1, Q2 may be penetrated from the workpiece 1 without applying an external stress, the workpiece 1 is damaged or the strength is reduced by the application of the external stress. Can be suppressed. Furthermore, since the etching is selectively advanced along the modified region 7 and the crack included in the modified region 7, the crack can be removed from the processed object 1 ′ after the processing. It is possible to improve the strength and quality of the object 1 ′. In addition, since no dust is generated due to machining unlike the case of cutting, an environment-friendly machining method can be realized.

  Further, in the present embodiment, as described above, after the modified region 7 is formed, a new modified region 7 is formed on the surface 3 side of the existing modified region 7, so that the existing modified region 7 is formed. It is possible to suppress the influence of the region 7 from reaching the newly formed modified region 7. Therefore, the modified region 7 can be formed with high accuracy.

  In the present embodiment, as described above, the step of irradiating the laser beam L while relatively moving the condensing point along the X direction is repeatedly performed by changing the position of the condensing point in the Z direction (FIG. 9). (See (a) to (c)). 9A to 9C are repeatedly performed by changing the position of the condensing point in the Y direction, thereby processing the modified region 7 along the outlines of the penetrating portions Q1 and Q2. Formed on the object 1. Therefore, it is possible to perform rapid processing while suppressing wasteful movement of the focal point, and it is possible to reduce the tact time (processing time) and thus reduce the cost.

  In the present embodiment, as described above, the modified region 7 formed inside the workpiece 1 by irradiation with the laser beam L is used, so that the workpiece 1 can be freely penetrated three-dimensionally. Can be processed.

  In the present embodiment, as shown in FIG. 10, the modified region 7 is exposed on the front surface 3 and the back surface 21 side of the workpiece 1. Instead, as shown in FIG. Alternatively, the crack C1 extending from the modified region 7 may be exposed on the front surface 3 side of the workpiece 1, or as shown in FIG. The crack C2 extending from the region 7 may be exposed. Furthermore, as shown in FIG. 14C, cracks C <b> 1 and C <b> 2 extending from the modified region 7 may be exposed on the front surface 3 and the back surface 21 side of the workpiece 1, respectively. In short, in order to infiltrate the inside of the etching agent during etching, it is only necessary that the crack included in the modified region 7 or extending from the modified region 7 reaches the outer surface of the workpiece 1.

  In the present embodiment, as described above, the piercing portions Q1 and Q2 are removed using the remove tape 17 (see FIG. 12). However, as shown in FIG. 15, an air adsorbing portion such as a porous chuck is used. 35 may be used to remove the penetrating portions Q1, Q2.

  Specifically, after performing the etching process on the workpiece 1, as shown in FIG. 15A, the workpiece 1 is turned upside down and the surface 3 is adsorbed by the air adsorbing portion 35. And as shown in FIG.15 (b), you may remove the piercing part Q1, Q2 from the workpiece 1 by moving so that the holding tape 16 may be lifted.

  Alternatively, after etching the workpiece 1, as shown in FIG. 16, the pierced portions Q <b> 1 and Q <b> 2 may be removed using an adhesive roller 36.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, differences from the first embodiment will be mainly described.

  In the present embodiment, the workpiece 1 is processed so as to pierce a plurality of pierced portions Q3, Q4. Here, the penetrating portions Q3 and Q4 have a truncated cone shape with the surface 3 as the bottom surface. That is, the penetrating portions Q3 and Q4 have a tapered portion 55 on the side surface that is inclined with respect to the Z direction (a direction orthogonal to the surface 3) so as to expand toward the surface 3 (one surface) of the workpiece 1.

  When processing the workpiece 1 in the present embodiment, first, as shown in FIG. 17A, by irradiating the workpiece 1 with the laser light L, the punched portions Q3, Q4 in the workpiece 1 are processed. The modified region 57 is formed along the outer shape. The modified region 57 is connected along the side surfaces of the pierced portions Q3 and Q4 each having a truncated cone shape, and is exposed on the front surface 3 side and the rear surface 21 side of the workpiece 1. The modified region 57 is formed in a step shape that is inclined with respect to the Z direction when viewed in the Y direction (X direction).

  Subsequently, as shown in FIG. 17B, the processing object 1 in which the modified region 57 is formed is subjected to an etching process, and the modified region 57 of the processing object 1 is removed. As shown, the punched-out portions Q3 and Q4 are moved so as to be extracted from the surface 3 side and removed from the workpiece 1. Thereby, it processes so that the piercing | piercing part Q3, Q4 of the workpiece 1 may be penetrated, and the through-hole 43 will be formed in the workpiece 1 as shown in FIG. Then, the processed object 1 ′ after processing is laminated on the device substrate 31 so that the through hole 43 is positioned on the device 32.

  As mentioned above, also in this embodiment, the said effect of improving the intensity | strength and quality of processed object 1 'after a process is show | played.

  Further, in the present embodiment, as described above, the modified region 57 that is inclined with respect to the Z direction when viewed in the Y direction is formed in the workpiece 1, and the punched portions Q3 and Q4 having the tapered portion 55 are penetrated. Yes. Therefore, the following effects are achieved. That is, it becomes easy to move the punched-out portions Q3, Q4 so as to be extracted from the surface 3 side, and it is possible to easily remove them from the workpiece 1. Further, when the processing object 1 ′ is laminated on the device substrate 31 after processing (see FIG. 18), the corners of the processing object 1 ′ are chamfered, so that the processing object 1 ′ is prevented from being chipped by impact. can do.

  In the present embodiment, as shown in FIG. 19, the modified region 57 is formed so that only a part on the surface 3 side is inclined and the others are along the Z direction in a side view, and only on the surface 3 side. You may process so that the punching parts Q3 and Q4 in which the taper part 55 was formed may be punched. In short, it is sufficient that the penetrating portions Q3 and Q4 have a tapered portion 55 that is inclined with respect to the Z direction.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In the description of the present embodiment, differences from the first embodiment will be mainly described.

  In the present embodiment, the workpiece 1 is processed so as to pierce a plurality of pierced portions Q5, Q6. The piercing portion Q5 includes a piercing portion Q5a on the front surface 3 side and a piercing portion Q5b on the back surface 21 side. Q6b is included.

  The penetrating portions Q5a and Q6a have a truncated cone shape with the surface 3 as the bottom surface, and have a tapered portion 71 inclined on the Z direction so as to expand toward the surface 3 side of the workpiece 1. On the other hand, the penetrating portions Q5b and Q6b have a truncated cone shape with the back surface 21 as the bottom surface, and have a tapered portion 72 inclined on the Z direction so as to expand toward the back surface 21 side of the workpiece 1. Yes.

  When processing the workpiece 1 in the present embodiment, first, as shown in FIG. 20 (a), the workpiece 1 is irradiated with the laser light L, thereby piercing portions Q5, Q6 in the workpiece 1. In addition to forming the modified region 77 along the outer shape, the modified region 78 is formed along the XY plane between the pierced portions Q5a and Q5b in the pierced portion Q5, and in the pierced portion Q6. A modified region 78 is formed along the XY plane between the punched portions Q6a and Q6b.

  The modified region 77 is connected along the side surfaces of the frustoconical pierced portions Q5 and Q6, and is exposed on the front surface 3 and back surface 21 side of the workpiece 1. The modified region 77 extends so as to be bent when viewed in the Y direction (X direction). The reformed region 78 extends along the XY plane so as to define pierced portions Q5a and Q5b at the center position in the Z direction within the reformed region 77, and is connected to the reformed region 77. The modified region 78 is formed in a straight line shape along the X direction (Y direction) when viewed in the Y direction (X direction), and is formed in a circular shape when viewed in the Z direction.

  Subsequently, by performing an etching process on the workpiece 1 to remove the modified region 77 of the workpiece 1 as shown in FIG. 20 (b), the workpiece 1 is processed as shown in FIG. 20 (c). The modified region 78 of the object 1 is removed. Subsequently, as shown in FIG. 20 (d), the punched-through portions Q5a, Q6a are moved so as to be removed from the front surface 3 side and removed from the workpiece 1, and the punched-through portions Q5b, Q6b are removed from the back surface 21 side. They are moved so as to be removed and removed from the workpiece 1.

  As a result, the punched portions Q5 and Q6 of the workpiece 1 are processed to be punched, and the through hole 53 is formed in the workpiece 1 as shown in FIG. The processed object 1 ′ after processing is laminated on the device substrate 31 so that the through hole 53 is positioned on the device 32.

  As mentioned above, also in this embodiment, the said effect of improving the intensity | strength and quality of processed object 1 'after a process is show | played.

  Further, in the present embodiment, as described above, the modified region 77 extending so as to be bent in the Y direction is formed on the workpiece 1 and penetrates the pierced portions Q5 and Q6 having the tapered portions 71 and 72. Yes. Therefore, the following effects are achieved. That is, it becomes easy to move the punched portions Q5a, Q6a so as to be extracted from the front surface 3 side, and it is easy to move the punched portions Q5b, Q6b so as to be extracted from the back surface 21 side. It is possible to easily remove the punched portions Q5 and Q6. Further, when the processing object 1 ′ is laminated on the device substrate 31 after processing (see FIG. 21), the corners of the processing object 1 ′ are chamfered so that the processing object 1 ′ is prevented from being chipped by impact. can do.

  In the present embodiment, as shown in FIG. 22A, the modified region 78 may be formed so that a crack C3 extending from the modified region 78 to the surface 3 occurs. In this case, the etching agent can be infiltrated into the inside by the crack C <b> 3 to facilitate and speed up the progress of etching along the modified region 78. Incidentally, in this case, instead of the crack C3 extending from the modified region 78 to the front surface 3, a crack extending from the modified region 78 to the back surface 21 may be generated.

  Further, as shown in FIG. 22B, the modified region 77 of the present embodiment is partially inclined on the front surface 3 side and the rear surface 21 side in the Y direction (X direction) view, and the space between them is in the Z direction. You may be comprised so that it may follow. In other words, the pierced portions Q5a and Q6a only need to have a tapered portion 71 on a part on the surface 3 side, and the pierced portions Q5b and Q6b only have a tapered portion 72 on a part on the back surface 21 side. .

  The preferred embodiments of the present invention have been described above. However, the laser processing method according to the present invention is not limited to the above-described embodiments, and may be modified or changed without departing from the scope described in each claim. It may be applied to the above.

  For example, the laser light incident surface when forming the modified region is not limited to the front surface 3 of the workpiece 1 but may be the back surface 21 of the workpiece 1. Moreover, in the said embodiment, although processed so that two penetration parts might be penetrated simultaneously, the number of penetration parts may be one and three or more may be sufficient.

  Moreover, although the said embodiment is a process for forming a through-hole in a process target object, it is not limited to this, The process for the external shape process of a process target object may be sufficient. That is, a punched portion (predetermined portion) may be a product.

  Moreover, in the said embodiment, although the modification | reformation area | region itself is connected along the external shape of the penetration part, the crack contained in the modification | reformation area | region 7 or extending from this modification | reformation area is connected along the external shape of the penetration part. Just do it.

  In addition, the ON / OFF irradiation of the laser beam L in the above embodiment controls the ON / OFF of the emission of the laser beam L, opens and closes a shutter provided on the optical path of the laser beam L, The surface 3 of the object 1 may be masked or the like. Furthermore, the intensity of the laser beam L may be controlled between an intensity that is equal to or higher than a threshold (processing threshold) at which the modified region is formed and an intensity that is less than the processing threshold.

  In the present invention, the step of irradiating the laser beam L while aligning the focal point at a predetermined position in the Z direction and moving the focal point in the X and Y directions along the modified region formation scheduled portion In some cases, the modified region is formed along the outer shape of the penetrating portion by repeatedly performing the above operation while changing the position of the condensing point in the Z direction.

  DESCRIPTION OF SYMBOLS 1 ... Workpiece, 3 ... Surface (one surface, outer surface), 7, 57, 77 ... Modified region (first modified region, second modified region), 21 ... Back surface (one surface, outer surface) 55, 71, 72 ... taper part, 78 ... modified region, C1-C3 ... crack, L ... laser beam, P ... condensing point, Q1-Q6 ... penetrating part (predetermined part).

Claims (4)

A laser processing method for processing to penetrate a predetermined portion of the processing object using a modified region formed by condensing laser light inside the processing object,
A laser beam irradiation step of forming the modified region along the outer shape of the predetermined portion of the workpiece by irradiating the workpiece with the laser beam;
After the laser beam irradiation step, by performing an etching process on the object to be processed, an etching process step of selectively progressing etching along a crack included in or extending from the modified region; and
A separation movement step of separating the predetermined portion from the workpiece after the etching treatment step, and
In the laser beam irradiation step, the modified region is formed so that the crack is connected along the outer shape, and the crack is exposed on the outer surface side of the workpiece. .   In the laser beam irradiation step, a first modified region is formed at a first depth position in the irradiation direction of the laser beam in the processing object, and then the laser beam in the processing object is more than the first depth position. The laser processing method according to claim 1, wherein the second modified region is formed at a second depth position on the light irradiation surface side. In the laser light irradiation step,
The step of irradiating the laser light while relatively moving the condensing point of the laser light along one direction orthogonal to the irradiation direction of the laser light is performed by changing the depth position of the condensing point in the irradiation direction. A first step to be repeated,
3. The second step of repeatedly performing the first step by changing the position of the condensing point in another direction orthogonal to the irradiation direction and the one direction. 4. Laser processing method.   The outer shape of the predetermined portion has a tapered portion that is inclined with respect to the orthogonal direction of the one surface so as to expand toward one surface side of the workpiece. The laser processing method according to any one of the above.

Images