JP2009172668A - Laser scribing apparatus and laser scribing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser scribing apparatus and a laser scribing method which can reliably determine, during forming a scribe line, whether or not the scribe line formed by the laser scribing method is normal. <P>SOLUTION: The invented laser scribing apparatus (10) is designed to form the scribe line (SB) on a predetermined splitting line (J) by causing relative movement of a laser beam (L) and a substrate (K) to be split so as to follow the predetermined splitting line (J) on the substrate (K) to be split. The laser scribing apparatus (10) is equipped with an imaging device (1) and a determining means (43). The imaging device (1) takes images (S1) of cracked portions on the scribe line (SB) just after forming the scribe line (SB). The determining means (43) determines in real time whether or not the scribe line (SB) is formed normally, on the basis of the images (S1) taken by the imaging device (1). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser scribing apparatus and a laser scribing method. More specifically, the present invention relates to an apparatus and a method for forming a scribe line using a laser beam on a planned cutting line on a substrate to be cut.

  Cleaving of brittle materials (hereinafter sometimes simply referred to as substrates) such as glass plates, ceramics or wafers is performed as follows. First, scribe lines are formed on the substrate surface. A scribe line is a shallow crack formed continuously on a planned cutting line in a substrate. Next, a physical force (bending moment) is applied around the scribe line, and a shallow crack is extended in the plate thickness direction of the substrate, thereby breaking (dividing) at the dividing line. For forming the scribe line, a mechanical scribe method using a mechanical blade such as a rotary blade (hereinafter referred to as a mechanical blade) or a laser scribe method using a laser beam is used.

  In the mechanical scribe method, a scribe line is formed by moving the substrate and the mechanical blade relative to each other from the start end to the end so as to follow the planned cutting line in a state where the substrate is in contact with the mechanical blade (see, for example, Patent Document 1).

  In the laser scribing method, an initial crack is first formed on the starting edge of the planned cutting line for the substrate. Next, the laser beam is heated within a short time from the beginning to the end so as to follow the planned cutting line, and the heated portion is rapidly cooled following the laser beam to form a scribe line (for example, a patent) Reference 2).

  When a scribe line is formed by a mechanical scribe method or a laser scribe method, a normal scribe line may not be formed. For example, in a mechanical scribe device, the mechanical blade is damaged or the height position of the mechanical blade is inappropriate. Further, in the laser scribing apparatus, the initial crack is not formed or the intensity of the laser beam is reduced during the operation of forming the scribe line.

  If a normal scribe line is not formed, the substrate cannot be cleaved in the breaking process. In particular, when the time gap during the transition from the scribe process to the break process is long, the abnormal notice is delayed and abnormal scribe lines are formed on many substrates. This causes a decrease in yield. In addition, rework is required, leading to an increase in production time. Therefore, it is necessary to determine whether the formed scribe line is normal or abnormal before cleaving.

In general, a scribe line formed by mechanical scribing can be visually recognized even if time elapses after the scribe line is formed. For this reason, the scribe line formed by mechanical scribing can be determined as normal / abnormal by a substrate appearance inspection technique using a camera (see, for example, Patent Document 3). This visual inspection step may be provided after the step of forming the scribe line so as to make a pass / fail judgment.
Japanese Patent Laid-Open No. 6-102480 JP-A-9-150286 JP 2001-33395 A

  On the other hand, the scribe line formed by the laser scribing method cannot be confirmed by visual observation or observation with an optical microscope after the scribing to the end is finished. If not, it is not known whether the scribe line was normal. This is because the crack on the substrate surface is closed soon after the scribe line is formed. There is a need for a technique that can reliably determine whether a scribe line formed by a laser scribe method is normal or not during scribe line formation.

  The present invention has been made in view of such circumstances, and a laser scribing apparatus capable of reliably determining whether a scribe line formed by a laser scribe method is normal or not during scribe line formation. And a laser scribing method.

  The above object is achieved by the present invention described below. The reference numerals in parentheses attached to each component in the “Claims” and “Means for Solving the Problems” column indicate the correspondence with the specific means described in the embodiments described later. It is.

  In the present invention, the laser beam (L) and the substrate to be cut (K) are moved relative to each other so as to follow the planned cutting line (J) in the substrate to be cut (K), thereby scribing on the cutting planned line (J). In the laser scribing apparatus (10) configured to form a line (SB), immediately after the scribe line (SB) is formed, an image (S1) of a crack occurrence portion (R) in the scribe line (SB) is taken. An imaging device (1) that performs the determination, and a determination unit (43) that determines in real time whether or not normal scribe line formation is performed based on an image (S1) obtained by imaging by the imaging device (1). It is characterized by providing.

  It is preferable to provide an alarm device (5) that issues an alarm when it is determined by the determining means (43) that an abnormal scribe line is being formed.

  The determination means (43) determines that the laser scribing operation is normal when the crack occurrence portion (R) can be recognized in the image (S1) obtained by imaging by the imaging device (1), and cannot recognize it. Is preferably configured to determine that the laser scribing operation is abnormal. Note that in the present invention, “alert an alarm” includes, for example, an alarm sound or a synthesized voice, an always-on lamp that is turned on, or the always-on lamp is turned off. Including form.

  In addition, the present invention is configured to move the laser beam (L) and the substrate to be cut (K) relative to each other so as to follow the planned cutting line (J) on the substrate to be cut (K). In the laser scribing method for forming a scribe line (SB), a step (145) of capturing an image (S1) of a crack occurrence portion (R) in the scribe line (SB) immediately after forming the scribe line (SB); And (147) determining in real time whether or not normal scribe line formation is performed based on the image (S1) of the crack occurrence portion (R) obtained by imaging.

  The function and effect of the present invention will be described. According to the present invention, the imaging device (1) captures an image (S1) of the crack occurrence portion (R) in the scribe line (SB) immediately after forming the scribe line (SB). The determination means (43) determines in real time whether or not normal scribe line formation is performed based on the image (S1) of the crack occurrence portion (R) obtained by imaging by the imaging device (1). Immediately after the scribe line is formed, the cracked portion (R) is in an open state and can be recognized.

  As shown in FIG. 6, the crack occurrence portion (R) is opened with a minute length (D1) and a minute width (D2) on both sides in the horizontal direction perpendicular to the scribe line (SB) with the scribe line (SB) as the center. It is an area to do. The crack occurrence portion (R) appears only immediately after the cooling mist (M) following the laser beam (L) is injected. In the present invention, whether or not scribe line formation is normal is determined by capturing this phenomenon with the imaging apparatus (1). The determination can be made based on, for example, both or one of the difference in the contrast and the difference in the shape of the image of the crack occurrence portion (R) obtained during normal scribe line formation. Thereby, it can be confirmed during scribe line formation whether the normal scribe line (SB) is formed reliably. If the scribe line formation is abnormal, it can be dealt with immediately, so that the substrate can be reliably cleaved in the breaking process. Further, it is possible to prevent abnormal scribe lines (SB) from being formed on many substrates in succession, and to improve the yield. At the same time, the production time is not extended.

  According to the present invention, whether or not a scribe line formed by a laser scribe method is normal can be reliably determined during scribe line formation.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic front view of a laser scribing apparatus 10 according to the present invention, FIG. 2 is a diagram illustrating a schematic configuration of an analysis computer, FIG. 3 is a flowchart illustrating a scribe line forming operation by the laser scribing apparatus 10, and FIG. It is a figure which shows the laser scribing operation | movement by the laser scribing apparatus 10 which concerns on planar view. In each configuration diagram, the three axes of the orthogonal coordinate system are X, Y, and Z, the XY plane is the horizontal plane, the Z direction is the vertical direction, and the rotation direction around the Z direction is the θ direction.

  As shown in FIG. 1, the laser scribing apparatus 10 includes a movable table 20, an initial crack forming mechanism 30, a laser light irradiation unit 40, a cooling unit 50, and a scribe state inspection apparatus 60. The initial crack formation mechanism 30, the laser light irradiation unit 40, the cooling unit 50, and the imaging device 1 are integrally fixed to the base 70 at a position higher than the movable table 20. The imaging device 1 is one of the components of the scribe state inspection device 60.

  The movable table 20 includes a table surface that can hold the placed substrate K by vacuum suction, and can be driven in each of XYZθ directions by a table driving device 21. When the scribe line is formed, it is driven in the Y1 direction.

  The initial crack forming mechanism 30 is configured to be able to form a very small initial crack C at the start end JS of the planned cutting line J in the substrate K placed and held on the movable table 20. As the component, a rotary blade unit 32 is provided. The rotary blade unit 32 has a rotary blade 31 that can be driven vertically.

  The laser beam irradiation unit 40 is configured to be able to irradiate the laser beam L output from the laser oscillator toward the surface of the substrate K from the laser irradiation window 41 via an optical system including a reflection mirror and an expanding lens. The The laser light L emitted from the laser irradiation window 41 has a sufficient output for forming the scribe line SB on the substrate K. The laser irradiation window 41 is provided at the rear portion of the rotary blade 31 with reference to the direction Y2 of the relative movement of the laser light L with respect to the movable table 20 when the scribe line is formed.

  The cooling unit 50 includes an injection nozzle 51 capable of injecting a mist-like cooling mist M. The injection nozzle 51 is provided in the rear part of the laser irradiation window 41 with reference to the direction Y2 of the relative movement of the laser light L with respect to the movable table 20 when the scribe line is formed. That is, it is provided so as to follow the laser beam L irradiated onto the substrate K when the scribe line is formed.

  The scribe state inspection device 60 includes an imaging device 1, an analysis computer 4, an alarm device 5, a control device 6, and the like.

  The imaging device 1 includes an imaging unit 2 that performs imaging with a shutter time specified in advance. The imaging unit 2 includes a CCD (Charge Coupled Device) mounted camera, and is configured to be able to transmit an image S1 acquired by imaging to the analysis computer 4 in real time. Moreover, it is comprised so that the light for illumination may be irradiated at the time of imaging. The arrangement position of the imaging device 1 is provided behind the cooling unit 50 with reference to the relative movement direction Y2 of the laser light irradiation unit 40 and the cooling unit 50 when the scribe line is formed. The imaging unit 2 is attached at a position where an image immediately after the cooling mist M ejected by the cooling unit 50 can be captured. That is, it is attached at a position where the image S1 of the crack occurrence portion in the scribe line SB can be taken following the cooling unit 50 when the scribe line is formed.

  As shown in FIG. 2, the analysis computer 4 has an image processing unit 43. The image processing unit 43 is configured to analyze whether or not the scribe line SB being formed is normal based on the image S1 sent from the imaging device 1. Specifically, when the scribe line SB can be recognized in the image S1 captured by the imaging device 1, it is determined that the laser scribing operation is normal, and when it cannot be recognized, it is determined abnormal and the abnormal signal S3 is detected. Is configured to output. The determination of normal / abnormal is configured so as to be performed according to parameters specified in advance. More specifically, the criterion for determining whether or not the image S1 is recognizable is configured to be performed based on or both of a difference in image contrast and a difference in shape. Such an image processing unit 43 is realized by appropriate hardware mainly including a memory chip and a microprocessor and a computer program incorporated therein.

  The alarm device 5 is configured to issue an alarm with a buzzer or a lamp when the abnormality signal S3 is received from the analysis computer 4.

  The control device 6 is configured to stop the laser light irradiation unit 40, the cooling unit 50, and the table driving device 21 and to excite the alarm device 5 based on the abnormal signal S3 output from the analysis computer 4.

  Next, the scribe line forming operation of the laser scribing apparatus 10 will be described with reference to FIGS.

  First, in step 100, the table driving device 21 connects the movable table 20 on which the substrate K is placed and held to the straight line t1 connecting the rotary blade 31 and the starting end JS of the planned cutting line J on the substrate K (see FIG. 4A). ) Is arranged so as to be parallel to the Y direction. Subsequently, in step 110, the initial crack formation mechanism 30 lowers the rotary blade 31 and places it at a position where the blade tip is lower than the surface of the substrate K.

  Subsequently, in step 120, the table driving device 21 drives the movable table 20 in the Y1 direction (see FIG. 4B). Due to the movement of the movable table 20, the rotary blade 31 collides with the start end JS of the planned cutting line J on the substrate K (step 124). Immediately thereafter, the initial crack formation mechanism 30 raises the rotary blade 31 (step 126). As a result, a very small initial crack C having a predetermined depth and length is formed at the starting end JS of the planned cutting line J.

  When the initial crack C is formed, the laser beam irradiation unit 40 irradiates the substrate K with the laser beam L from the laser irradiation window 41 in step 130. In Step 140, the cooling unit 50 ejects the cooling mist M from the ejection nozzle 51 so as to follow the laser beam L. Due to the relative movement of the laser beam L and the cooling mist M with respect to the substrate K, the laser beam L suddenly heats the planned cutting line J and locally expands thermally by generating a compressive stress from the starting end JS. Immediately after that, the mist M rapidly cools the heated portion and locally contracts to generate tensile stress. As a result, the initial crack C is used as the starting point of crack propagation, and microcracks along the planned cutting line J are continuously grown on the surface of the substrate K to form the scribe line SB.

  At the time of forming the scribe line SB, the imaging device 1 captures an image S1 of a crack occurrence portion in the scribe line SB in real time and transmits it to the analysis computer 4 (step 145). The analysis computer 4 determines whether or not the image processing unit 43 can recognize the image S1 captured by the imaging device 1 (step 147), and as long as the image S1 can be recognized (Yes in step 150), the analysis schedule is scheduled. The laser scribing operation is continued until reaching the end JE of the line J. When the scribe line SB is formed up to the end JE (Yes in Step 170), the irradiation of the laser light L, the injection of the cooling mist M, and the traveling of the movable table 20 are stopped (Step 180).

  If there is a portion where the captured image cannot be recognized before reaching the end JE of the planned cutting line J (No in step 150), the image processing unit 43 determines that the laser scribing operation is abnormal and causes an abnormality. The signal S3 is output. The control device 6 outputs a device control signal S4 in response to the abnormal signal S3. The alarm device 5 is excited by the device control signal S4 to generate an alarm (step 160), and the irradiation of the laser light L, the injection of the cooling mist M, and the traveling of the movable table 20 are stopped (step 180).

  Thus, according to the laser scribing apparatus 10, it can be confirmed during the scribe line formation whether or not the normal scribe line SB is reliably formed. If the scribe line formation is abnormal, it can be dealt with immediately, so that the substrate can be reliably cleaved in the breaking process. Further, it is possible to prevent abnormal scribe lines from being formed on many substrates in succession, and to improve the yield. At the same time, the production time is not extended.

  Hereinafter, the present invention will be described with reference to examples. FIG. 5 is a schematic front view of the laser scribing apparatus 11 used in the embodiment of the present invention. FIG. 6 is a diagram showing a normal image and an abnormal image obtained by the laser scribing apparatus 11 shown in FIG. 6 (A) shows an image when normal, and FIG. 6 (B) shows an image when abnormal. In each figure, a hatched portion in the substrate K indicates a portion not irradiated with illumination light, and a non-hatched portion indicates a portion irradiated with illumination light.

  Immediately after the injection nozzle 51 in the conventional laser scribing device 11 that does not have the scribing state inspection device 60, the imaging device 1 is attached as shown in FIG. 5 and connected to the camera monitor 8 via the image processing unit 7, and is normal. Images were observed during laser scribe and abnormal laser scribe.

Specific specifications at this time are as follows.
[Substrate] Manufacturing company: Corning Corporation, Model number: EAGLE2000,
Type: 0.5mm thick glass substrate [table speed] 300mm / sec
[Camera] Manufacturer: Keyence Corporation, Model Number: CV-35M
[Image processing unit] Manufacturing company: Keyence Corporation, model number: CV-3000
[Camera Monitor] Manufacturer: Winmate, Model: R15L630-RMC3

  The abnormal scribe line was formed by increasing the power of the laser beam L. If the laser power is higher than the specified value, the scribe line SB will wave or stop halfway. If it is lower than the specified value, the scribe line SB stops without progressing from the initial crack. As described above, when the laser output deviates from the regulation value, the injection amount of the cooling mist M deviates from the regulation value, or the scribe speed deviates from the regulation value, the scribe line Since SB cannot be recognized, it can be determined whether the scribe formation is normal or abnormal scribe formation.

  As mentioned above, although embodiment of this invention was described, embodiment disclosed above is an illustration to the last, Comprising: The scope of the present invention is not limited to this embodiment. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a schematic front view of a laser scribing apparatus according to the present invention. It is a figure which shows the structure outline | summary of the computer for analysis. It is a figure which shows planarly the laser scribing operation | movement by the laser scribing apparatus which concerns on this invention. It is a flowchart which shows the scribe line formation operation | movement by a laser scribing apparatus. It is the front schematic of the laser scribing apparatus used for the Example of this invention. It is a figure which shows the image at the time of normal scribe line formation and the image at the time of abnormal scribe line formation which were obtained by the laser scribing apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 5 Alarm device 10 Laser scribing device 43 Image processing part (determination means)
145 Step 147 Step J Planned cutting line K Substrate (Substrate to be cut)
L Laser light S1 Image SB Scribe line

Claims (6)

The scribe line (SB) is placed on the planned cutting line (J) by relatively moving the laser beam (L) and the cutting board (K) so as to follow the planned cutting line (J) on the cut board (K). In a laser scribing device (10) configured to form
An imaging device (1) that captures an image (S1) of a crack occurrence portion (R) in the scribe line (SB) immediately after forming the scribe line (SB);
Determination means (43) for determining in real time whether or not normal scribe line formation is performed based on the image (S1) of the crack occurrence portion (R) obtained by imaging by the imaging device (1). A laser scribing apparatus.   The laser scribing apparatus according to claim 1, further comprising an alarm device (5) that issues an alarm when it is determined by the determination means (43) that an abnormal scribe line is being formed.   The determination means (43) determines that the laser scribing operation is normal when the crack occurrence portion (R) can be recognized in the image (S1) obtained by imaging by the imaging device (1), and cannot recognize it. The laser scribing apparatus according to claim 1, wherein the laser scribing operation is determined to be abnormal. The scribe line (SB) is placed on the planned cutting line (J) by relatively moving the laser beam (L) and the cutting board (K) so as to follow the planned cutting line (J) on the cut board (K). In a laser scribing method for forming
Immediately after forming the scribe line (SB), a step (145) of capturing an image (S1) of the cracked portion (R) in the scribe line (SB);
And (147) determining in real time whether or not normal scribe line formation is performed based on the image (S1) of the crack occurrence portion (R) obtained by imaging, Method.   The laser scribing method according to claim 4, wherein an alarm is issued when it is determined by the determination that an abnormal scribe line is being formed.   The laser scribing operation is determined to be normal if the crack occurrence portion (R) can be recognized in the image (S1) obtained by the imaging, and the laser scribing operation is determined to be abnormal if the crack cannot be recognized. The laser scribing method according to claim 4 or 5.

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