JP2011020140A - Laser scribing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method that detects an actually scribed position while performing laser scribing and that performs feedback correction so as to approach a predetermined planned cutting line. <P>SOLUTION: In the laser scribing apparatus, a heating beam composed of a laser beam is emitted so that a scribing line is formed along the predetermined planned cutting line on a substrate to be cut, and a coolant is sprayed. The apparatus uses: a scribing line generating position detection means which detects the generating position of the scribing line; a scribing position deviation calculating means which calculates deviation of the generating position of the scribing line with respect to the planned cutting line; and a scribing position changing means by which the generating position of the scribing line with respect to the planned cutting line can be changed. There is also provided a laser scribing method. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an apparatus and a method for forming a scribe line on a planned cutting line set on a substrate to be cut.

  In the manufacturing process of flat panel displays and semiconductor chips, a method of forming a number of products on one wafer or substrate (hereinafter referred to as a substrate) and then dividing it into a predetermined size is adopted in order to increase manufacturing efficiency. Yes. The flat panel display and the semiconductor chip are made of a brittle material such as glass, ceramics, or silicon, and the substrate is divided (hereinafter, cleaved) as follows.

  First, scribe lines are formed on the surface of the substrate to be cut. The scribe line is a shallow crack formed continuously on the planned cutting line in the substrate to be cut.

  Next, a bending moment is applied around the formed scribe line, and a shallow crack is extended in the plate thickness direction of the substrate to be cut, so that the substrate to be cut is cleaved at the planned cutting line.

One method of forming the scribe line is a laser scribe method.
What is laser scribing?
1) Set the planned cutting line on the substrate to be cut in advance.
2) A heating beam using an infrared laser is irradiated so as to trace the planned cutting line along the planned cutting line, and the surface of the substrate to be cut is heated.
3) Follow the heated part, spray a cooling mist, cool the heated part,
This is a method of forming continuous shallow cracks on the surface of the substrate to be cut by continuously performing the heating and the cooling.

  In the laser scribing method, a minute initial crack is formed at the cutting start end portion of the substrate to be cut on the planned cutting line. Since the heating and the cooling are continuously performed from the initial crack portion, continuous shallow cracks are formed on the surface of the substrate to be cut.

  The heating beam has a predetermined width and length, and by the irradiation of the heating beam, the heat absorbed on the surface of the cut substrate is internally transmitted, and the temperature inside the cut substrate is also increased. At this time, the heated portion is in a state where a force for expanding the material by heating is applied.

  Next, when the heated portion is cooled, a force for contracting the material is applied. At this time, the surface of the substrate to be cut is cooled and a force to contract is applied, but the temperature inside the material of the substrate to be cut is still high and the force to expand remains applied. spread. Thereafter, the substrate surface and the internal temperature become uniform, and the crack becomes invisible.

  The cleaved substrate subjected to laser scribing is cleaved on the assumption that the laser scribing is correctly performed on the planned cutting line.

  The laser scribing method utilizes a change in force generated on the surface and inside of the substrate to be cut, which is generated by continuously performing heating and cooling. Therefore, maintaining the balance of force leads to improving the straightness of the scribe line.

  According to Patent Document 1, a technique is disclosed in which the crack can be recognized by spraying a marking agent on a crack portion formed by laser scribing.

  According to Patent Document 2, when the substrate to be cut is cut by irradiating the scribe line formed by laser scribing again with the laser, the position of occurrence of the cut is detected and the location is judged to be appropriate. A technique for adjusting is disclosed.

JP2008-018723 Special table 2008-503355

  When the brittle material is cleaved by the laser scribing method, the straightness of the scribe line changes if the balance of the force acting near the heating part, the cooling part, or the planned breaking line changes.

FIG. 5 shows a plan view of a substrate cleaved by a conventional laser scribing apparatus and method.
For the substrate to be cut 10, the cutting lines 81a, 82a, 83a are set. The actual cutting lines for the planned cutting lines 81a, 82a, 83a are 81b, 82b, 83b. This state is a typical example when laser scribing is not performed correctly.

  The actual cleaving line 81b deviates from the cleaving planned line 81a in the middle of cleaving, and the cleaving stops in the middle.

  Although the actual cutting line 82b meanders somewhat with respect to the cutting planned line 82a, it is formed substantially along the cutting planned line 82a.

  The actual cutting line 83b is along the planned cutting line 83a, but is formed at a distance from the planned cutting line 83a.

  As mentioned above, if laser scribing is not performed correctly, the cleaving stops midway and the substrate cannot be cleaved, the width of the meander after cleaving is larger than a desired value, or it is cleaved with a deviation from a predetermined position. Or

As a factor that changes the balance of force that changes the straightness of the scribe line,
When the shape or temperature distribution of the heating beam changes due to changes in the laser transmitter or optical components over time,
When the cooling mist particle distribution, spray shape, spray position, etc. change,
When there is variation in the internal composition and thickness uniformity of the substrate to be cut,
When there is a variation in parallelism between the substrate to be cut and the means for supporting the substrate,
The case where there is a change in the external force such as the force for holding the substrate that works from the means for supporting the substrate to be cut.

  The above-mentioned factors may appear suddenly or have a small degree of influence on the actual straightness. If the laser scribing device is processed and assembled within the range of general tolerances or predetermined tolerances, In some cases, it was acceptable. However, high processing accuracy has been required for products incorporating a substrate that has been cleaved by laser scribing, and has become difficult to tolerate.

  Therefore, matching the scribe line that is actually formed with the preset planned cutting line leads to an improvement in processing accuracy, and is important when assembling a product incorporating the cut substrate.

  In the laser scribing method, whether or not the processing accuracy of the scribe line is within a specified range is not known unless it is actually cleaved. However, the use of a marking agent in the cracked part often contaminates the substrate to be cut and requires a post-cleaning step, and thus cannot be employed in many cases.

  If the scribe line was formed only halfway or the processing accuracy of the scribe line was poor, even if it was found after cleaving the substrate, a defective product has occurred, Production must be interrupted and readjusted.

  Furthermore, much time and labor have been spent on the work of readjusting the processing position of the scribe line and the work for confirming whether it is within an allowable range.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus and a method for performing feedback correction so as to detect a position that is actually scribed while performing laser scribing and to approach a preset planned cutting line.

In order to solve the above problems, the invention described in claim 1
A laser scribing device comprising means for irradiating a heating beam made of a laser beam and means for spraying a coolant so that a scribe line is formed along a preset planned cutting line on a substrate to be cut In
Position detecting means for detecting the generation position of the scribe line;
A positional deviation amount calculating means for calculating a deviation amount of the generation position of the scribe line with respect to the planned cutting line;
A laser scribing apparatus comprising: a scribing position changing means capable of changing a generation position of a scribing line with respect to the planned cutting line.

The invention described in claim 2
2. The laser scribing apparatus according to claim 1, wherein the generation position of the scribe line can be adjusted using the information from the displacement amount calculation means during the formation of the scribe line.

The invention according to claim 3
The scribe position changing means includes at least either a means for changing the irradiation position of the heating beam or a means for changing the position where the coolant is sprayed. This is a laser scribing apparatus.

The invention according to claim 4
In a laser scribing method, comprising a step of irradiating a heating beam composed of a laser beam and a step of spraying a coolant so that a scribe line is formed along a preset planned cutting line on a substrate to be cut ,
A position detecting step for detecting a generation position of the scribe line;
A displacement amount calculation step for calculating a displacement amount of the generation position of the scribe line with respect to the planned cutting line,
A laser scribing method comprising a scribing position changing step of adjusting a generation position of a scribing line with respect to the planned cutting line.

The invention described in claim 5
The step of adjusting the generation position of the scribe line in the scribe position change step using the information in the positional deviation amount calculation step while forming the scribe line,
A laser scribing method according to claim 4.

The invention described in claim 6
The said scribe position change step has either the step which changes the irradiation position of the said heating beam at least, or the step which changes the position which sprays the said coolant, The Claim 4 or Claim 5 characterized by the above-mentioned. This is a laser scribing method.

  Since the apparatus and method of the present invention are used, a scribe line with high straightness can be formed.

It is a perspective view of the laser scribing apparatus of this invention. It is the principal part block diagram which showed the main equipment structure of the scribe head part of this invention. It is a system configuration figure of the laser scribing device of the present invention. It is a flowchart which shows the procedure of the laser scribe of this invention. It is a top view of the board | substrate cleaved by the conventional laser scribing apparatus and method.

FIG. 1 is a perspective view showing a laser scribing apparatus.
FIG. 2 is a main part configuration diagram showing the main equipment configuration of the scribe head part of the laser scribing apparatus. In each figure, the three axes of the orthogonal coordinate system are X, Y, and Z, the XY plane is the horizontal plane, and the Z direction is the vertical direction.

  The laser scribing apparatus 1 includes a portal-type structure including an apparatus base 11, a column 12 attached on the apparatus base 11, and a beam portion 13 attached on the column 12. . Further, the laser scribing apparatus 1 includes a stage unit 2, a scribing head unit 3, a controller for controlling devices in each unit, and a control unit 9 in which devices for operating the device are housed. Configured.

  The stage unit 2 includes an X-axis stage 21 attached on the apparatus base 11 and a table 22 attached on the X-axis stage 21. The X-axis stage 21 can move the table 22 in the X direction.

  On the table 22, the substrate to be cut 10 is placed. Grooves and holes are provided on the surface of the table 22, and the grooves and holes are connected to a vacuum source via an opening / closing control valve. The to-be-cut substrate 10 placed on the table 22 is sucked and held by a negative pressure so as not to be displaced during movement.

  Since the stage part 2 is configured as described above, the substrate to be cut 10 placed on the table 22 can be moved in the X direction.

  The scribe head unit 3 is attached to a Y1 axis stage 31 attached to a gate-shaped structure made up of a column 12 and a beam 13 attached on the device base 11 of the laser scribe device 1, and in the Y direction. It is configured to be able to move to.

  The scribe head unit 3 includes a box-shaped housing 30 having an open bottom surface, and is attached to the inside of the housing 30, and includes an initial crack forming unit 4, a laser beam irradiation unit 5, a cooling unit 6, and a scribe. The position detection unit 7 is included.

  The initial crack forming means 4 includes an actuator 41, a wheel holder 42 attached to the actuator 41, and a scribe wheel 43 attached to the wheel holder 42.

  When the actuator 41 moves downward in the Z direction, the wheel holder 42 and the scribe wheel 43 move downward in the Z direction, and the scribe wheel 43 is pressed against the substrate 10 to be cut, so A minute initial crack 40 can be attached.

  The laser beam irradiation unit 5 includes a Y2 axis stage 54 attached to the housing 30 of the scribe head unit 3, a holder 55 attached to the Y2 axis stage 54, and a mirror 53 attached to the holder 55. A lens 56 is included.

  A laser beam 52 irradiated from the laser transmitter 51 and guided using a mirror, a lens, or the like is irradiated toward the mirror 53 of the laser beam irradiation unit 5. The laser beam 52 applied to the mirror 53 is reflected at a different angle and applied to the lens 56.

  The laser beam irradiated on the lens 56 is shaped into a predetermined shape and is irradiated as a heating beam 50 toward the cut substrate 10.

  The Y2 axis stage 54 can move the holder 55 in the Y direction. Thereby, the irradiation position of the heating beam 50 to the substrate 10 to be cut can be moved in the Y direction.

  The cooling unit 6 includes a coolant supply means for supplying a coolant such as a refrigerant made of air, water, other fluids or a mixture, and a cooling nozzle 61 that is a means for spraying the coolant toward the glass substrate. It is configured.

  The cooling nozzle 61 is mounted on a Y3-axis stage 62 mounted on the housing 30 of the scribe head unit 3 and can be moved in the Y direction. Thereby, the spray position of the cooling mist 60 with respect to the to-be-cut substrate 10 can be moved to a Y direction.

  The scribe position detection unit 7 includes a position detector 71. The measurement light beam 70 is irradiated from the position detector 71 toward the substrate to be cut 10.

  The measurement light beam 70 is reflected by the substrate to be cut 10 and is applied to the light receiving portion of the position detector 71. The light beam applied to the light receiving unit can detect the unevenness of the surface of the substrate to be cut and the position in the Y direction of the portion 10c opened immediately after laser scribing.

  The substrate to be cut 10 is moved in the direction indicated by the arrow 20 while being placed on the table 22. In addition, by using the scribe wheel 43 of the initial crack forming means 4, a minute initial crack 40 is attached to the end portion of the preset planned cutting line 10 a.

  After the initial crack 40 is made, the actuator 41 is moved upward in the Z direction, and the scribe wheel 43 is moved away from the cut substrate 10.

  Subsequently, the planned cutting line 10 a is heated by the heating beam 50 emitted from the laser beam irradiation unit 5 and cooled by the cooling mist 60 blown from the cooling unit 6. By this series of operations, a minute initial crack 40 becomes a starting point, and a process called laser scribing is performed on the surface of the substrate to be cut 10, and an actual scribe line 10b is continuously formed.

  The actual scribe line 10b cannot be detected at all by optical observation means over time. However, immediately after the substrate to be cut 10 is heated and cooled, a part of the upper surface is opened, although it is very slight. The position detector 71 is disposed in the vicinity of the cooling nozzle 61 so that the opened portion 10c can be observed, and the measurement portion 70 of the position detector 71 is irradiated with the opened portion 10c.

FIG. 3 is a system configuration diagram of the laser scribing apparatus of the present invention.
As shown in FIG. 3, a control computer 90, information input means 91, information output means 92, reporting means 93, information recording means 94, and device control unit 95 are connected to the control unit 9. Has been included.

Examples of the control computer 90 include a computer equipped with a numerical operation unit such as a microcomputer, a personal computer, or a workstation.
Examples of the information input unit 91 include a keyboard, a mouse, and a switch.
Examples of the information output unit 92 include an image display display and a lamp.

Examples of the reporting means 93 include those that can alert the operator, such as a buzzer, a speaker, and a lamp.
Examples of the information recording means 94 include a semiconductor recording medium, a magnetic recording medium, a magneto-optical recording medium, such as a memory card and a data disk.
Examples of the device control unit 95 include devices called programmable controllers and motion controllers.

  The device control unit 95 includes an X-axis stage 21, a Y1-axis stage 31, an actuator 41 of the initial crack generating means unit 4, a laser transmitter 51, a control valve for ON / OFF switching of the mist 60, and a Y2-axis stage. 54, Y3-axis stage 62, position detector 71, and other control devices (not shown) are connected.

  The device control unit 95 can operate and stop each device by giving a control signal to each connected device.

  The scribe position and various conditions necessary for the scribe are set by using the information input means 91 connected to the control computer 90 of the control unit 9 and can be confirmed by the information display means 92. The setting can be read, edited, and changed as appropriate, and can be registered in the information recording means 94 connected to the control computer 90.

FIG. 4 is a flowchart showing a laser scribing procedure performed using the laser scribing apparatus 1 for each step.
The substrate 10 to be cut is placed on the table 22 (s101), and the substrate 10 to be cut is sucked and held (s102).

  Next, the alignment mark on the substrate to be cut 10 is read (s103), and the alignment operation of the substrate to be cut 10 placed on the table 22 is performed.

  Next, a laser scribing operation is performed along the planned cutting line 10a on the substrate to be cut 10 (s104). At this time, the position detector 71 is used to detect the position of the opened portion 10c immediately after scribing, and it is detected as the actual generation position of the scribe line 10b (s105).

  Next, a deviation amount in the Y direction of the actual generation position of the scribe line 10b with respect to the planned cutting line 10a is calculated (s106).

  Next, it is determined whether or not the deviation amount in the Y direction is within an appropriate range set in advance (s107).

  If the amount of deviation in the Y direction is within an appropriate range, scribe is continued (s108), and it is determined whether or not one line of scribe has been completed (s109).

  If scribing is in progress, scribing is continued, the generation position of the scribe line is detected again (s105), and the steps (s106 to s109) are continued.

  If the scribe for one line is completed, it is determined whether or not all the scribes are completed (s110). If other scribing is necessary, a laser scribing operation is performed along the planned cutting line on the substrate to be cut 10 (s104), and the steps (s105 to s110) are continued.

  When all the scribes are completed, the substrate mounting table 22 is moved to the cut-out position of the substrate to be cut.

  Next, adsorption of the substrate to be cut 10 is released (s111), and the substrate to be cut 10 is taken out from the substrate mounting table 22 (s112).

  If the amount of deviation in the Y direction is not within the proper range in step s107, the operation is continued according to cases A to C selected in advance (s113).

  Case A: The irradiation position of the heating beam 50 and the spray position of the cooling mist 60 are changed in the Y direction, and the generation position of the scribe line is changed (s114).

  At this time, if the actual generation position of the scribe line 10b is shifted by 50 μm in the direction of the arrow in the Y direction with respect to the planned cutting line 10a, the irradiation position of the heating beam 50 and the spray position of the cooling mist 60 are set to Y. Shift 50 μm in the direction opposite to the direction arrow. By doing so, the actual generation position of the scribe line 10b comes close to the planned cutting line 10a.

  Case B: Continue scribing in the same state (s115). Case C: The scribe is interrupted (s116). Thereafter, the reporting means 93 notifies the operator that the amount of deviation in the Y direction of the scribe position is out of the appropriate range (s117).

  In step s114, it is set in advance whether only the irradiation position of the heating beam is changed, only the spray position of the cooling mist is changed, or both are changed. Further, the position of the entire scribe head may be changed in the Y direction.

  As described above, the laser scribing apparatus 1 calculates the amount of displacement of the position of the scribing line 10a with respect to the position detection unit 7 that is a position detection unit that detects the position of occurrence of the scribing line and the planned cutting line 10a. Since the control computer 90, which is a quantity calculation means, is configured to include the control unit 9, laser scribing is performed on the planned cutting line set on the substrate 10 to be cut, and then immediately after that, actually The position of the scribed and opened portion 10c can be known.

  In addition, since it is configured to include at least either the irradiation position changing means of the heating beam 50 or the blowing position changing means of the cooling mist 60, the laser beam is within the range in the Y direction set in advance on the planned cutting line 10a. The irradiating position of the heating beam 50 and the spraying position of the cooling mist 60 can be sequentially changed while feedback correction so that scribing can be performed.

  The conditions for feedback correction, such as how much to change the irradiation position of the heating beam 50 or the spray position of the cooling mist 60, may be determined based on the results of tests performed in advance. The feedback correction conditions may be registered in the information recording means 94 of the control unit 9 and read out appropriately by the control computer 90 for use.

  By doing as mentioned above, a scribe line with high straightness can be formed, and when the substrate is cleaved in the next process, the dimensional accuracy of the cut section is increased. Due to the high dimensional accuracy of the fractured surface, it is possible to reduce the problem that when fitting into the frame, the dimensions cannot be fitted without fitting.

  Even when a material that serves as a buffer material is injected between the frame and the substrate to be cut, an appropriate gap can be maintained. As a result, the buffer material can be used appropriately and strength reduction can be prevented.

  In addition, when a substrate to be cut having a residual stress is scribed inside the substrate to be cut, when the flatness of the table 22 is poor, or an external force is applied to the substrate to be cut by the way of holding the substrate to be cut or gravity. In such a case, in the conventional laser scribing apparatus and method, a phenomenon like the actual breaking line 81b shown in FIG. 5 frequently occurred.

  However, in the laser scribing apparatus and method of the present invention, a continuous scribe line was formed without greatly deviating from a preset planned cutting line. For this reason, the number of substrates discarded due to cleaving defects is reduced, and the yield is improved.

As the substrate 10 to be cut, non-alkali glass having a thickness of 500 mm in the X direction, 400 mm in the Y direction and 0.7 mm (thickness) in the Z direction is used, and laser scribing is performed at a speed of 200 mm / second in the direction of the arrow 20 It was. When laser scribing was performed using a conventional apparatus and method, it was in the range of ± 70 to 100 μm in the Y direction. After laser scribing using the apparatus and method of the present invention, the position of the actual cleaving line after cleaving was measured and found to be within a range of ± 10 to 30 μm in the Y direction with respect to the preset cleaving line. It was. Therefore, it was recognized that the straightness of the scribe line was improved by using the apparatus and method of the present invention.

DESCRIPTION OF SYMBOLS 1 Laser scribing apparatus 2 Stage part 3 Scribing head part 4 Initial crack formation means 5 Laser beam irradiation unit 6 Cooling unit 7 Scribing position detection part 9 Control part 10 Substrate to be cut 10a Scheduled cutting line 10b Actual scribe line 10c Open part 11 Device base 12 Column 13 Beam portion 20 Arrow 21 X-axis stage 22 Table 30 Housing 31 Y1-axis stage 40 Initial crack 41 Actuator 42 Wheel holder 43 Scribe wheel 50 Heating beam 51 Laser transmitter 52 Laser beam 53 Mirror 54 Y2-axis stage 55 Holder 56 Lens 60 Cooling mist 61 Cooling nozzle 62 Y3 axis stage 70 Measuring beam 71 Position detector 81a Scribe line 81b Actual breaking line 82a Scribe line 82b Actual Break line 83a Scheduled scribe line 83b Actual break line 90 Control computer 91 Information input means 92 Information display means 93 Notification means 94 Information recording means 95 Equipment control unit

Claims (6)

A laser scribing device comprising means for irradiating a heating beam made of a laser beam and means for spraying a coolant so that a scribe line is formed along a preset planned cutting line on a substrate to be cut In
Position detecting means for detecting the generation position of the scribe line;
A positional deviation amount calculating means for calculating a deviation amount of the generation position of the scribe line with respect to the planned cutting line;
A laser scribing apparatus comprising: a scribing position changing unit capable of changing a generation position of a scribing line with respect to the planned cutting line. During the formation of the scribe line, it is possible to adjust the generation position of the scribe line using information from the displacement amount calculation means,
The laser scribing apparatus according to claim 1. The scribing position changing means includes at least either a means for changing the irradiation position of the heating beam or a means for changing the position where the coolant is sprayed.
The laser scribing apparatus according to claim 1 or 2. In a laser scribing method, comprising a step of irradiating a heating beam composed of a laser beam and a step of spraying a coolant so that a scribe line is formed along a preset planned cutting line on a substrate to be cut ,
A position detecting step for detecting a generation position of the scribe line;
A displacement amount calculation step for calculating a displacement amount of the generation position of the scribe line with respect to the planned cutting line,
A laser scribing method comprising: a scribing position changing step of adjusting a generation position of a scribing line with respect to the planned cutting line. The step of adjusting the generation position of the scribe line in the scribe position change step using the information in the positional deviation amount calculation step while forming the scribe line,
The laser scribing method according to claim 4. The scribing position changing step includes at least either a step of changing an irradiation position of the heating beam or a step of changing a position where the coolant is sprayed.
The laser scribing method according to claim 4 or 5.

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