Laser processing methods
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- HAMAMATSU PHOTONICS KK
- Filing Date
- 2014-03-18
- Publication Date
- 2026-07-23
AI Technical Summary
Laser processing methods face challenges when dealing with objects bonded by materials that poorly transmit light, such as metals and certain resins, as the processing lines in the first and second planar members are difficult to align due to the opaque bonding layer, leading to reduced processing quality.
A method that forms a modified region in the first planar member, then creates a processing scar in the bonding layer, and finally aligns the laser irradiation position for the second planar member using the scar as a reference, ensuring precise alignment despite the opaque bonding layer.
This approach maintains processing quality by precisely aligning the modified areas in both planar members, even with light-blocking bonding layers, and can reduce overall processing time by simultaneous formation of the modified region and scar.
Abstract
Description
Technical field
[0001] One aspect of the present invention relates to a laser processing method for processing an object to be processed which has a pair of planar elements stacked on top of each other and a bonding layer bonding them together. State of the art
[0002] Patent literature 1 describes a method for dividing an object to be processed, which utilizes a laser light beam. In this object division method, while a laser light beam illuminating the object from one side is focused near the other surface of the object, the object and the laser light beam are moved relative to each other along a division line to create a modified area in the object along the division line. Subsequently, in the object division method, a bending moment is applied to the object around the division line to break the object along the division line. Reference list of patent literature
[0003] Patent literature 1: Published Japanese patent application no. 2004-343008 Summary of the invention: Technical problem
[0004] Recently, a requirement arose for laser processing of an object formed by joining a pair of planar elements (first and second planar elements) together via a predetermined bonding layer. For example, the following procedure can be used to perform laser processing on such an object. First, laser light incident on the side of the first planar element illuminates the second planar element through the first planar element and the bonding layer to create a modified region in the second planar element along a desired line to be processed. Then, laser light incident on the side of the first planar element illuminates the first planar element to create a modified region in the first planar element along the line to be processed.
[0005] However, in some cases, a material with low light transmission (examples include metals and certain resins) is used as a bonding layer for bonding the first and second planar elements. If laser processing is performed on an object with such a bonding layer, it becomes difficult to irradiate the second planar element with laser light from the side of the first planar element through the bonding layer, as described above. Therefore, in this case, after the modified area has been formed in the first planar element by irradiating it with laser light from that side, the object is turned over so that the second planar element is irradiated with laser light from that side to create the modified area.
[0006] If, in this case, the second planar element is irradiated with laser light from the side of the second planar element to form the modified area within it, the position to be irradiated with the laser light must be aligned with a processing line (a modified area formed along the line to be processed) that was previously formed in the first planar element. However, the bonding layer, which is barely transmissive to light and is located between the first and second planar elements, means that the processing line in the first planar element is not easily detected by, for example, an infrared camera. Therefore, the processing line in the first planar element and the processing line in the second planar element may not be aligned, thus reducing the processing quality.
[0007] In view of this, it is an object according to one aspect of the present invention to specify a laser processing method that can suppress a reduction in processing quality. Problem solving
[0008] To solve the aforementioned problem, the laser processing method according to one aspect of the present invention comprises: a first step for preparing an object to be processed, which has first and second planar elements stacked on top of each other, and a bonding layer arranged between the first and second planar elements, bonding the first and second planar elements together, wherein the object is provided with a line to be processed; a second step for forming a modified area in the first planar element along the line by irradiating the first planar element with laser light along the line, wherein a front surface of the object on one side opposite the bonding layer on the first planar element is used as a laser light entry surface;a third step to form a processing scar in the bonding layer along the line by irradiating the bonding layer with laser light along the line, the front surface of the object being used as a laser light entry surface; and a fourth step, following the first to third steps, to form a modified area in the second planar member along the line by irradiating the second planar member with laser light along the line, a rear surface of the object on a side opposite the bonding layer on the second planar member being used as a laser light entry surface; wherein the fourth step irradiates the second planar member with laser light along the line by using the processing scar formed in the bonding layer as a reference for aligning a laser light irradiation position with respect to the second planar member.
[0009] This laser processing method irradiates a first planar segment with laser light to form a modified area in the first planar segment along a line to be cut, and irradiates a bonding layer, which bonds the first and second planar segments together, with laser light to form a processing scar in the bonding layer along the line. If a modified area is formed in the second planar segment, the second planar segment is irradiated with laser light along the line, using the processing scar formed in the bonding layer as a reference for alignment to form a modified area in the second planar segment along the line.Even if the bonding layer is made of a material that transmits very little light, such as a metal or a specific resin, the processing line (the modified area along the line to be processed) in the first planar segment, which is formed earlier, can be precisely aligned with the processing line in the second planar segment, which is formed later. Therefore, this laser processing method can suppress any reduction in processing quality.
[0010] The laser processing method according to one aspect of the present invention can form the modified region in the first planar segment by performing the third step after forming the processing scar in the bonding layer. In this case, prior to forming the modified region for the first planar segment, the bonding layer, which is located further inside the object than the first planar segment, is irradiated with laser light to form the processing scar. This prevents the processing scar of the bonding layer from interfering with the modified region formed in the first planar segment by irradiation with laser light from the side of the first planar segment.
[0011] The laser processing method according to one aspect of the present invention can perform the third step by irradiating the bonding layer with leakage light from the laser light to irradiate the first planar element during the execution of the second step in order to form the processing scar in the bonding layer. In this way, the second step for forming the modified area in the first planar element and the third step for forming the processing scar in the bonding layer can be performed simultaneously, thereby reducing the overall processing time. Advantageous effects of the invention
[0012] According to one aspect of the present invention, a laser processing method can be provided which can suppress a reduction in processing quality. Brief description of the drawings
[0013] Fig. Figure 1 is a schematic view of a laser processing device used to form a modified area.
[0014] Fig. Figure 2 is a top view of an object to be processed, on which the modified area is formed.
[0015] Fig. Figure 3 is a sectional view of the object along line III-III of Fig. 2.
[0016] Fig. Figure 4 is a top view of the object after laser processing.
[0017] Fig. Figure 5 is a section view of the object along line VV. Fig. 4.
[0018] Fig. Figure 6 is a sectional view of the object along line VI-VI of Fig. 4.
[0019] Fig. Figure 7 is a flowchart showing the main steps of the laser processing method according to a first embodiment.
[0020] Fig. Figure 8 is a diagram showing an object to be processed using the laser processing method.
[0021] Fig. Figure 9 is a diagram that illustrates one step in processing a bonding layer.
[0022] Fig. Figure 10 is a diagram that illustrates one step in processing a first planar member.
[0023] Fig. Figure 11 is a diagram that illustrates one step for transferring the object and one step for processing a second planar member.
[0024] Fig. Figure 12 is a diagram that illustrates one step in processing a second planar member.
[0025] Fig. Figure 13 is a flowchart showing the main steps of the laser processing procedure according to a second embodiment.
[0026] Fig. Figure 14 is a diagram illustrating a step in the processing of the first planar element and the bonding layer. Description of embodiments
[0027] The laser processing method according to one embodiment of an aspect of the present invention is described in detail below with reference to the drawings. Identical or corresponding components are indicated by the same reference numerals in the drawings, and repeated descriptions are omitted here.
[0028] The laser processing method according to one embodiment of an aspect of the present invention comprises a case in which an object to be processed is irradiated with laser light along a line to be cut (process line) in order to form a modified area that becomes a cutting start point in the object along the line. Therefore, the formation of the modified area with reference to Fig. 1 to Fig. 6 described without any restriction regarding the material of the object.
[0029] As in Fig. Shown in 1, it includes a laser processing device 100 a laser light source 101 , which causes laser light L to oscillate in a pulsating manner, a dichroic mirror 103 , which is arranged in such a way that it changes the direction of the optical axis (of the optical path) of the laser light L by 90°, and a converging lens 105 for collecting the laser light L. The laser processing device 100 also includes a holding table 107 to hold an object to be processed 1 , the one with the converging lens 105 The collected laser light L is irradiated, a stage 111 to move the holding table 107 , a laser light source control device 102 to control the laser light source 101 , to adjust the output, pulse width, pulse waveform, etc. of the laser light L, and a stage control device 115 to regulate the movement of the stage111 .
[0030] In the laser processing device 100 This changes the laser light source 101 The emitted laser light L changes the direction of its optical axis by 90° using the dichroic mirror. 103 and is then passed through the converging lens 105 into the one at the holding table 107 mounted object 1 collected. At the same time, the stage is 111 shifted so that the object 1 relative to the laser light L along a line to be cut 5 moved. In this way, a modified area is created within the object. 1 along the line 5 trained.
[0031] As the object 1 A planar component (e.g., a substrate or a wafer) made of various materials (e.g., glass, semiconductor materials, and piezoelectric materials) is used. As in Fig. As shown in 2, the line 5 to cut the object1 in the object 1 set. The line 5 is a virtual line that extends straight. If a modified area in the object 1 When formed, the laser light L is directed relatively along the line 5 moved (i.e. in the direction of arrow A from Fig. 2), while a gathering point P in the object 1 as in Fig. 3 is positioned as shown. This creates a modified area. 7 in the object 1 along the line 5 as in Fig. 4 to Fig. 6 shown formed, with the one along the line 5 trained modified area 7 a cutting start area 8 becomes.
[0032] The collection point P is a position where the laser light L is collected. The line 5 It can also be curved instead of straight, or it can be a line that actually lies on a front surface. 3 of the object1 is drawn and therefore not a virtual line. The modified area 7 Training can be continuous or intermittent. The modified area 7 can be formed in rows or points and only needs to be at least in the object 1 They are trained. Under certain circumstances, fractures can occur in the modified area. 7 are trained, which serve as a starting point, with the fractures and the modified area 7 on the outer surfaces (front surface) 3 , back surface 4 and outer perimeter area) of the object 1 can be exposed.
[0033] The laser light L is emitted during its passage through the object. 1 especially in the vicinity of the collection point P in the building 1 absorbed, thereby the modified area 7 in the object 1is formed (laser processing with internal absorption). Therefore, the front surface absorbs. 3 of the object 1 The laser light L barely melts and does not melt. If a distance feature such as a hole or a groove is formed by cutting it from the front surface 3 When melting occurs (surface absorption laser processing), the processing area generally progresses gradually from the side of the front surface. 3 to the side of the back surface 4 forward.
[0034] In this embodiment, a modified region is understood to be a region whose physical properties, such as density, refractive index, and mechanical strength, differ from those of the surrounding regions. Examples of a modified region include molten regions, fractured regions, dielectric breakdown regions, regions with a changed refractive index, and regions composed of these. Other examples of a modified region are regions where the density of the modified region has been changed from that of a non-modified region, and regions that have been provided with a lattice defect in the object's material (these can collectively be referred to as high-density transition regions).
[0035] The molten areas, areas with a changed refractive index, areas where the modified area has a different density than the unmodified area, or areas with a lattice defect may still exhibit a fracture (a crack or microfracture) within it or at an interface between the modified and unmodified areas. The integrated fracture may be present across the entire surface of the modified area, or only in one part, or in a multitude of parts. Examples of the object 1 are substrates and wafers made of silicon, glass, LiTaO3 and sapphire (Al2O3) and objects containing such substrates and wafers.
[0036] This embodiment forms a multitude of modified points (processing scars) along the line. 5 out, to the modified area 7to generate. The modified points, each of which is a modified part formed by a pulse of pulsed laser light (i.e., by a pulse of laser irradiation; laser shot), collectively form the modified area. 7 Examples of modified points are fracture points, melted points, points with a changed refractive index, and points with mixtures of these.
[0037] The size and length of fractures originating from the modified points can be controlled with regard to the required cutting accuracy, the required flatness of the cut surfaces, the thickness, the type and crystal orientation of the object, etc. [First embodiment]
[0038] The laser processing method according to the first embodiment of an aspect of the present invention is described below. The laser processing method according to this embodiment processes an object formed by joining a pair of planar elements. The cutting of an object along a desired cutting line (processing line) is described below. Fig. Figure 7 is a flowchart showing the main steps of the laser processing procedure according to the first embodiment. Fig. Figure 8 is a diagram showing the object to be processed using the laser processing method. It is... Fig. 8(b) a partial sectional view along line VIII-VIII of Fig. 8(a).
[0039] As in Fig. As shown in 8, the object 1First, the object is prepared using this laser processing method (first step). An example of the object... 1 is a workpiece for a predetermined functional device. The object 1 includes a first planar element 11 , a second planar member 12 and a bonding layer 13 The first and second planar elements 11 , 12 are stacked on top of each other. The bonding layer 13 is between the first and second planar members 11 , 12 arranged. The bonding layer 13 bondet the first and second planar links 11 , 12 each other.
[0040] The area on which the bonding layer is located is 13 opposite side of the first planar segment 11 the front surface 3 of the object 1 , while the area on the side opposite the bonding layer 13on the second planar segment 12 the back surface 4 of the object 1 is the front surface 3 of the object 1 is the converging lens 105 turned towards (see Fig. 1) The object 1 is to be intersected with a straight line 5 provided, extending from one end to the other end.
[0041] The first and second planar members 11 , 12 They are made of materials such as glass or silicon. The first and second planar elements 11 , 12 They can be made of the same material or of different materials. The materials of the first and second planar elements 11 , 12 and their forms are selected according to the desired function of the device. The first and second planar elements exhibit 11 , 12It has an essentially rectangular, planar shape. Therefore, the object also exhibits this characteristic. 1 Overall, it has an essentially rectangular, planar shape.
[0042] It can be any material that forms the first and second planar members 11 , 12 can bond together, as a material for the bonding layer 13 can be used. Specific examples of materials for the bonding layer. 13 These are metals (e.g., Au) and resins (e.g., polyimide). In particular, the bonding layer can 13 They may consist of a material that hardly allows the processing laser light or observation light in IR cameras and the like to pass through (e.g., a metal such as Au or a thickly applied resin such as polyimide).
[0043] Then, as in Fig. 7 and Fig. Figure 9 shows the bonding layer 13 processed (step S101: third step). Fig. Figure 9 is a diagram that illustrates a step in the processing of the bonding layer. In particular, it is Fig. 9(b) a partial sectional view along line IX-IX of Fig. 9(a).
[0044] This step S101 creates processing marks (damage marks: modified parts) 17 in the bonding layer 13 by irradiating the bonding layer 13 with laser light L1 through the first planar segment 11 through from the side of the first planar segment 11 One example of such a modification is softening by heating during irradiation with laser light and hardening by subsequent cooling.
[0045] In particular, step S101 initially positions a collection point P1 of the laser light L1 in the bonding layer. 13 , wherein the front surface 3 (Surface on the side opposite the bonding layer 13 at the first planar segment11 ) of the object 1 It is used as an entry point for the laser light L1. In this state, the object 1 moved relative to the laser light L1, so that the bonding layer 13 with the laser light L1 along the line 5 irradiated (scanned).
[0046] This results in processing scars. 17 in the bonding layer 13 along the line 5 for example, designed with intervals corresponding to the pulse width of the laser light L1 (relative speed of movement of the object). 1 with respect to the laser light L1) / (frequency of the pulse oscillation of the laser light L1)). Step S101 forms the processing scars. 17 essentially over the entire length of the bonding layer 13 by irradiating the object 1from one end to the other using laser light L1. The radiation conditions for laser light L1 can be adjusted such that the processing marks 17 not only into the interior of the bonding layer 13 not only the bonded interfaces, but also the bonded surfaces between the bonding layer 13 and the first and second planar members 11 , 12 (and especially the second planar element) 12 ) achieve, whereby the processing scars 17 They can also be connected continuously to each other.
[0047] With such training in the bonding layer 13 along the line 5 The processing scar will 17 exposed at one end surface (cut surface) of each chip, which is exposed when the object is cut 1 along the line 5 is formed. However, because the bonding between the first and second planar elements 11 ,12 in each chip through the entire surface of the bonding layer 13 The manufacturing process reduces the processing scar. 17 The bonding strength between the first and second planar elements is not determined at the end surface of each chip. 11 , 12 Because of the processing scars 17 by modifying the bonding layer 13 The bonding layer can only be formed by irradiation with laser light L1; this prevents the bonding layer from forming. 13 Dust is produced or partially falls off or detaches when the object 1 along the line 5 is cut.
[0048] Then, as in Fig. 7 and Fig. 10 shows the first planar element 11 processed (step S102: second step). Fig. Figure 10 is a diagram that illustrates a step in processing the first planar term. In particular, it is Fig. 10(b) a partial sectional view along line XX of Fig. 10(a). This step S102 forms a modified area 7 in the first planar member 11 by irradiating the first planar segment 11 with laser light L2 from the side of the first planar segment 11 .
[0049] In particular, this step S102 initially positions a collection point P2 of the laser light L2 in the first planar member. 11 , wherein the front surface 3 of the object 1 It is used as an entry point for the laser light L2. In this state, the object 1 moved relative to the laser light L2, so that the first planar element 11 with the laser light L2 along the line 5 is irradiated (scanned). In this way, the modified area is 7 in the first planar member 11 along the line 5trained. This step S102 forms the modified area. 7 essentially over the entire length of the first planar segment 11 out by removing the object 1 from one end to the other end is irradiated with laser light L2. Step S102 can determine the position at which the modified area 7 in the thickness direction of the first planar member 11 is trained, hired, or can perform a variety of modified ranges. 7 in the first planar member 11 in accordance with the material and thickness of the object 1 with the first planar element contained therein 11 , to achieve the desired cutting accuracy, etc.
[0050] Then the object 1 as in Fig. 7 and Fig. 11 shown transferred (step S103). This means that the object 1 In this step S103 is reversed, so that the back surface4 (the area on which the bonding layer is located 13 opposite side of the second planar member 12 ) of the object 1 the converging lens 105 is turned towards. Fig. Figure 11 is a diagram that illustrates one step for transferring the object and one step for processing the second planar member. In particular, Fig. 11(b) a partial sectional view along line XI-XI of Fig. 11(a).
[0051] Then, as in Fig. 7, Fig. 11 and Fig. 12 shows the second planar term 12 processed (step S104: fourth step). Fig. Figure 12 is a diagram that illustrates a step in processing the second planar term. In particular, Fig. 12(b) a partial sectional view along line XII-XII of Fig. 12(a). Step S104 forms a modified section 7 in the second planar member 12from, by the second planar term 12 with laser light L3 from the side of the second planar segment 12 from irradiated.
[0052] To this end, step S104, as in Fig. Figure 11 shows at the beginning the irradiation position of the laser light L3 (the position of a collecting point P3 of the laser light L3) in relation to the laser light L3 in directions (in the directions of the arrows in the drawing) which indicate the thickness direction of the second planar member. 12 and the direction of extension of the line 5 cross. This includes, in particular, a processing line formed in the preceding step S103. 6 of the first planar member 11 and one in the second planar member 12 In this step S104, the processing line is formed (which is in the second planar link). 12 along the line 5(formed modified area) are aligned with each other, the irradiation position of the laser light L3 in relation to the second planar element will be 12 onto the processing line 6 of the first planar member 11 set. For the sake of simplicity, it shows Fig. 11 the processing line 6 of the first planar member 11 on the back surface 4 of the object 1 .
[0053] In this laser processing method, the lines are processed along the line. 5 aligned processing scars 17 in the bonding layer 13 formed, which are closer to the second planar segment 12 is arranged as the first planar member 11 So even if the processing line 6 (the modified area) 7 ) of the first planar element 11 not directly from the side of the second planar member 12The irradiation position of the laser light L3 can be detected with the processing line. 6 of the first planar member 11 be aligned by aligning the processing scars 17 from the side of the second planar member 12 for example, they can be detected using an IR camera and the irradiation position of the laser light L3 in relation to the processing scars can be determined. 17 is set. Thus, by creating the processing scars. 17 the bonding layer 13 When used as a reference for an alignment, step S104 can be the second planar member. 12 with the laser light L3 along the processing line 6 (i.e. the line 5 ) irradiate.
[0054] Then step S104 positions as in Fig. Figure 12 shows the collection point P3 of the laser light L3 in the second planar member. 12 , wherein the back surface 4 of the object 1It is used as an entry point for the laser light L3. In this state, the object 1 moved relative to the laser light L3, so that the first planar element 11 with the laser light L3 along the line 5 (and the processing line) 6 ) is irradiated (scanned). This makes the modified area visible. 7 in the second planar member 12 along the line 5 (and the processing line) 6 trained.
[0055] Step S104 forms the modified area 7 essentially over the entire length of the second planar segment 12 out by removing the object 1 from one end to the other is irradiated with laser light L3. Step S104 can also adjust the position at which the modified area is located. 7 in the thickness direction of the second planar member 12is trained, or a variety of series of modified areas 7 in the second planar member 12 in accordance with the material and thickness of the object 1 with the second planar element contained therein 12 , producing the desired cutting accuracy, etc.
[0056] For example, a tension is created along the line 5 on the object 1 exercised in which the modified areas 7 in the first and second planar members 11 , 12 along the line 5 are trained to handle the object 1 from the modified areas serving as starting points 7 to cut from the outset.
[0057] As explained above, the laser processing method according to the first embodiment irradiates the first planar element. 11 with the laser light L2 to modify the area 7in the first planar member 11 along the line 5 to train, and irradiates the bonding layer 13 , which are the first and second planar members 11 , 12 connects them, with the laser light L1, to process the scars 17 in the bonding layer 13 along the line 5 to train. If the modified area 7 in the second planar member 12 When processed, the components in the bonding layer are... 13 trained processing scars 17 used as a reference for an alignment to determine the second planar member 12 with the laser light L3 along the line 5 (i.e., the processing line) 6 ) to irradiate and thereby modify the area 7 in the second planar member 12 along the line 5 (i.e., the processing line) 6 ) to train.
[0058] So even if the bonding layer 13 is formed from a material that barely transmits light, such as a metal or a predetermined resin, and can be used in the first planar segment. 11 trained processing line 6 and those later in the second planar member 12 The trained processing line must be precisely aligned with each other. Consequently, this laser processing method can suppress any reduction in processing quality.
[0059] In particular, the laser processing method according to this embodiment irradiates before the modified area is formed. 7 in the first planar member 11 the bonding layer 13 , which are located further inside the object 1 is located as the first planar element 11 , with the laser light L1, to remove the processing scars 17 to train. This can prevent the processing scars from forming.17 the bonding layer 13 the one in the first planar member 11 by irradiation with laser light L2 from the side of the first planar segment 11 from a trained, modified area 7 impair.
[0060] Before cutting the object 1 The laser processing method according to this embodiment forms damage scars (processing scars). 17 ) along the line 5 in which the first and second planar members 11 , 12 bonding layer bonding together 13 This prevents the bonding layer from being cut. 13 along the line 5 when cutting the object 1 simplified, which can improve the processing quality. [Second embodiment]
[0061] The following describes the laser processing method according to a second embodiment of an aspect of the present invention. The laser processing method according to this embodiment also cuts an object to be processed, which is formed by attaching a pair of planar elements together, as in the laser processing method according to the first embodiment. Fig. Figure 13 is a flowchart showing the main steps of the laser processing method according to the second embodiment. The laser processing method prepares the object. 1 first as in Fig. 8 shown before (first step).
[0062] Then, as in Fig. 13 and Fig. 14 shows the first planar element 11 and the bonding layer 13 processed simultaneously (step S201: second and third steps). Fig. Figure 14 is a diagram illustrating a step in the processing of the first planar member and the bonding layer. In particular, Fig. 14(b) a partial sectional view along line XIV-XIV of Fig. 14(a). Step S201 forms a modified section 7 in the first planar member 11 and processing scars 17 in the bonding layer 13 by irradiating the first planar segment 11 and the bonding layer 13 with laser light L4 from the side of the first planar segment 11 out of.
[0063] In particular, step S201 establishes a state at the beginning in which the front surface 3 of the object 1 is used as an entry surface for the laser light L4, so that a collecting point P4 of the laser light L4 is located in the first planar member 11 is positioned while the bonding layer 13The object is irradiated with leakage light (laser light) L5 of the laser light L4. In this state, the object 1 moved relative to the laser light L4 to form the first planar segment 11 along the line 5 with the laser light L4 and the bonding layer 13 to irradiate (scan) with the leakage light L5 of the laser light L4.
[0064] This will modify the area 7 in the first planar member 11 along the line 5 and the processing scars 17 in the bonding layer 13 along the line 5 trained. Step S201 forms the modified area. 7 and the processing scars 17 essentially over the entire length of the first planar segment 11 and the bonding layer 13 by irradiating the object 1from one end to the other using laser light L4. Step S201 can also set the position at which the modified area 7 in the thickness direction of the first planar member 11 is trained, or can be a variety of series of modified areas. 7 in the first planar member 11 in accordance with the material and thickness of the object 1 with the first planar element contained therein 11 , the desired cutting accuracy, etc.
[0065] The following steps of this laser processing method are the same as those of the laser processing method according to the first embodiment. The laser processing method transfers (turns) the object. 1 as in Fig. 8 and Fig. 11 shown (step S202) and then irradiates the second planar segment 12 with the laser light L3 from the side of the second planar segment12 as in Fig. 8, Fig. 11 and Fig. 12 shown to illustrate the modified area 7 in the second planar member 12 (Step S203: fourth step) to form. Then a mechanical stress is applied to the object. 1 along the line 5 exercised to the object 1 from the modified area serving as the starting point 1 to cut from the outset.
[0066] For the same reason as in the first embodiment, the laser processing method described above, according to the second embodiment, can replace the processing line. 6 of the first planar member 11 even then exactly with the processing line of the second planar link 12 align when the bonding layer 13 It is made of a material that hardly lets any light through. This helps to prevent a reduction in processing quality.
[0067] In particular, the laser processing method according to the second embodiment can simultaneously perform the step of forming the modified area. 7 in the first planar member 11 and the step towards forming the processing scars 17 in the bonding layer 13 perform this, thereby reducing the overall processing time.
[0068] The foregoing embodiments illustrate one mode for carrying out the laser processing method according to one aspect of the present invention. The laser processing method according to one aspect of the present invention is not limited to the laser processing methods of the first and second embodiments described above. The laser processing method according to one aspect of the present invention can arbitrarily switch between the laser processing methods of the first and second embodiments without thereby departing from the scope of the invention.
[0069] For example, while the laser processing methods of the first and second embodiments produce the processing scars 17 over the entire length of the bonding layer 13 In steps S101 and S201, the processing scars can be formed. 17 even in only part of the bonding layer 13 along the line 5 They will be trained because it is sufficient if the processing scars 17 the bonding layer 13 as a reference for the orientation during the processing of the second planar member 12 can be used in a later step.
[0070] The laser processing methods according to the first and second embodiments are used for adjusting the area extending from one end of the object. 1 to the other end of the line 5used, although the laser processing method according to one aspect of the present invention is not limited thereto. The laser processing method according to one aspect of the present invention can be applied to laser processing for cutting off a part of the object. 1 can be used, for example, to modify the object 1 to bring it into a desired shape. In this case, it is sufficient if one line to be processed is present in the object. 1 is set in accordance with the desired position and shape for cutting. Industrial applicability
[0071] One aspect of the present invention may provide a laser processing method which may limit a reduction in processing quality. List of reference symbols 5 : object to be processed; 3 : Front surface; 4 : Back surface; 5 : line to be cut (line to be processed);7 : modified area; 11 : first planar element; 12 : second planar member; 13 : Bonding layer; 17 : Processing scar; L1, L2, L3, L4: Laser light; L5: Leakage light.
Claims
[1] Laser processing techniques, comprising: a first step in preparing an object to be processed, comprising first and second planar elements stacked on top of each other, and a bonding layer arranged between the first and second planar elements, bonding the first and second planar elements together, wherein the object is provided with a line to be processed, a second step to form a modified area in the first planar segment along the line by irradiating the first planar segment with laser light along the line, wherein a front surface of the object on one side opposite the bonding layer on the first planar segment is used as a laser light entry surface, a third step to form a processing scar in the bonding layer along the line by irradiating the bonding layer with laser light along the line, using the front surface of the object as a laser light entry surface, and a fourth step, after the first to third steps, to form a modified area in the second planar segment along the line by irradiating the second planar segment with laser light along the line, wherein a rear surface of the object on a side opposite the bonding layer on the second planar segment is used as a laser light entry surface, wherein the fourth step irradiates the second planar member with laser light along the line by using the processing scar formed in the bonding layer as a reference for aligning a laser light irradiation position with respect to the second planar member. [2] Laser processing method according to claim 1, wherein the modified area in the first planar member is formed by carrying out the third step after forming the processing scar in the bonding layer. [3] Laser processing method according to claim 1, wherein the third step is carried out by irradiating the bonding layer with leakage light of the laser light to irradiate the first planar member during the execution of the second step in order to form the processing scar in the bonding layer.