TWI833743B - Laser machining device, laser machining system and laser machining method - Google Patents

Abstract

This invention aims to measure the position in the vertical direction of an irradiation point of a machining laser light beam on the upper surface of a substrate with a small-sized laser displacement meter. A laser machining device of this invention comprises a height measurement section for measuring the position in the vertical direction of an irradiation point of a machining laser light beam on the upper surface of a substrate, and a control section that makes the irradiation point move on plural expected parting lines on the upper surface of the substrate while simultaneously controlling the position in the vertical direction of a light focusing section based on the position in the vertical direction of the irradiation point. The height measurement section comprises a measurement laser oscillator for oscillating a measurement laser light beam having a frequency different from that of the machining laser light beam, and a reflected light receiving section for receiving the reflected light of the measurement laser light beam irradiated on the upper surface of the substrate through a pathway overlapping with the machining laser light beam from the middle. When performing the machining of an aforementioned substrate with an aforementioned machining laser light beam, the control section conducts an output change of the measurement laser oscillator based on the intensity of reflected light received by the reflected light receiving section.

Description

Laser processing device, laser processing system and laser processing method

The invention relates to a laser processing device, a laser processing system and a laser processing method.

The main surface of a substrate such as a semiconductor wafer is divided by a plurality of dicing lanes formed in a grid shape, and devices such as elements, circuits, and terminals are preliminarily formed in each of the divided areas. Wafers can be obtained by dividing the substrate along a plurality of dicing lanes forming a grid shape. The substrate is divided using, for example, a laser processing device.

The laser processing device of Patent Document 1 includes: a light collection point position adjustment mechanism that displaces the light collection point position of the processing laser beam used to process the substrate; and a height position detection mechanism that detects the top surface of the substrate. Height position; and a control mechanism that controls the light collection point position adjustment mechanism according to the detection signal from the height position detection mechanism. Thereby, the modified layer can be formed at a predetermined depth position that is uniformly distanced from the top surface of the substrate.

The height position detection mechanism of Patent Document 1 includes a laser displacement meter that irradiates the top surface of a substrate with a measurement laser beam and receives the reflected light to measure the height of the top surface of the substrate. The measurement laser light has a different wavelength from the processing laser light, and has the same wavelength as the processing laser light from a dichroic mirror (Dichroic Mirror) installed in the middle of the path of the processing laser light to the top surface of the substrate. path.

A dichroic mirror allows laser light of a specific wavelength (such as laser light for processing) to pass through while reflecting laser light of other specific wavelengths (such as laser light for measurement). This makes it possible to simultaneously irradiate a point on the top surface of the substrate with the laser light for processing and the laser light for measurement. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2009-269074

[Problem to be solved by the invention]

It has been desired that the laser displacement meter that measures the vertical position of the irradiation point of the laser beam for processing on the top surface of the substrate will be miniaturized.

One embodiment of the present invention mainly aims to use a small laser displacement meter to measure the vertical position of the irradiation point of the processing laser light on the top surface of the substrate. [Methods to solve problems]

A laser processing device according to an embodiment of the present invention is characterized by including: a substrate holding part that holds the substrate horizontally from below; a processing laser oscillation part that oscillates to emit processing laser light for processing the substrate; an irradiation point moving unit that moves the irradiation point of the processing laser light on the top surface of the substrate held by the substrate holding unit; a height measurement unit that measures the vertical position of the irradiation point; and a light collecting unit that The processing laser light is concentrated from above the irradiation point downward; the light collecting part moving part makes the light collecting part move in the vertical direction; and the control part makes the irradiation point on the top of the substrate. The vertical direction position of the light collecting part is controlled according to the vertical direction position of the irradiation point while moving along a plurality of planned dividing lines of the surface; the height measuring part includes: a measuring laser oscillation part, the oscillation of which emits a laser with a frequency similar to that of the processing laser. a measuring laser light having a different wavelength; and a reflected light receiving unit that receives the reflected light of the measuring laser light that irradiates the top surface of the substrate along the same path as the processing laser light from the middle ; The control unit is configured to change the output of the measurement laser oscillation unit based on the intensity of the reflected light received by the reflected light receiving unit while the substrate is being processed with the processing laser light. . [Efficacy of the invention]

According to an embodiment of the present invention, a small laser displacement meter can be used to measure the vertical position of the irradiation point of the processing laser light on the top surface of the substrate.

Hereinafter, aspects for implementing the present invention will be described with reference to the drawings. In each drawing, the same or corresponding symbols are attached to the same or corresponding structures, and explanations are omitted. In the following description, the X-axis direction, the Y-axis direction, and the Z-axis direction are mutually perpendicular directions, the X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is the vertical direction. The direction of rotation with the vertical axis as the center of rotation is also called the θ direction. In this manual, below means below in the vertical direction, and above means above in the vertical direction.

FIG. 1 is a perspective view of a substrate before being processed by the substrate processing system according to the first embodiment. The substrate 10 is, for example, a semiconductor substrate, a sapphire substrate, or the like. The first main surface 11 of the substrate 10 is divided by a plurality of dicing lanes formed in a grid shape, and devices such as components, circuits, and terminals are preliminarily formed in each of the divided areas. A wafer can be obtained by dividing the substrate 10 along a plurality of dicing lanes forming a grid shape. The planned dividing line 13 is set on the cutting path.

A protective tape 14 is bonded to the first main surface 11 of the substrate 10 (see FIG. 6 ). The protective tape 14 protects the first main surface 11 of the substrate 10 during laser processing to protect devices preformed on the first main surface 11 . The protective tape 14 covers the entire first main surface 11 of the substrate 10 .

The protective tape 14 is composed of a sheet-like base material and an adhesive coated on the surface of the sheet-like base material. The adhesive may be one that hardens when exposed to ultraviolet rays and reduces its adhesive force. After the adhesive force is reduced, the protective tape 14 can be simply peeled off from the substrate 10 through a peeling action.

In addition, the protective tape 14 may also be installed on the frame to cover the opening of the annular frame, and be bonded to the substrate 10 at the opening of the frame. At this time, the substrate 10 can be transported while holding the frame, and the operability of the substrate 10 can be improved.

FIG. 2 is a top view showing the substrate processing system according to the first embodiment. In FIG. 2 , the carry-in cassette 35 and the carry-out cassette 45 are cut off, and the inside of the carry-in cassette 35 and the carry-out cassette 45 are shown.

The substrate processing system 1 is a laser processing system that performs laser processing on the substrate 10 . The substrate processing system 1 includes a control unit 20, a loading unit 30, an unloading unit 40, a transport path 50, a transport unit 58, and various processing units. The processing unit is not particularly limited, but for example, the alignment unit 60 and the laser processing unit 100 are provided.

In addition, in this embodiment, the transport unit 58 corresponds to the transport device described in the patent claims, the alignment unit 60 corresponds to the alignment device described in the patent claims, and the laser processing unit 100 corresponds to the laser described in the patent claims. Injection processing equipment.

The control unit 20 is composed of, for example, a computer. As shown in FIG. 2 , it has a CPU (Central Processing Unit) 21 , a recording medium 22 such as a memory, an input interface 23 , and an output interface 24 . The control unit 20 instructs the CPU 21 to execute the program stored in the recording medium 22 to perform various controls. In addition, the control unit 20 receives signals from the outside through the input interface 23 and sends signals to the outside through the output interface 24 .

The program of the control unit 20 is stored in the information recording medium and installed from the information recording medium. Examples of information recording media include hard disks (HD), floppy disks (FD), optical disks (CD), magneto-optical disks (MO), and memory cards. In addition, the program can also be downloaded and installed from the server through the Internet.

The carry-in cassette 35 is carried into the carry-in part 30 from the outside. The carry-in section 30 is provided with a placement plate 31 on which the carry-in cassette 35 is placed. The plurality of placement plates 31 are arranged in a row in the Y-axis direction. In addition, the number of mounting plates 31 is not limited to that shown in the figure. The cassette 35 is loaded and accommodates a plurality of pre-processed substrates 10 at intervals in the Z-axis direction.

When carrying the cassette 35 into the cassette 35, in order to prevent the protective tape 14 from being deformed such as curling, the substrate 10 can be stored horizontally with the protective tape 14 facing upward. The substrate 10 taken out from the loading cassette 35 is turned upside down and then transported to a processing unit such as the alignment unit 60 .

The carry-out cassette 45 is carried out from the carry-out part 40 to the outside. The unloading unit 40 is provided with a placing plate 41 on which the unloaded cassette 45 is placed. The plurality of placement plates 41 are arranged in a row in the Y-axis direction. In addition, the number of mounting plates 41 is not limited to that shown in the figure. The cassette 45 is unloaded and a plurality of processed substrates 10 are stored at intervals in the Z-axis direction.

The conveyance path 50 is a path through which the conveyance unit 58 conveys the substrate 10 , and extends in the Y-axis direction, for example. The Y-axis guide part 51 extending in the Y-axis direction is provided in the conveyance path 50, and the Y-axis slide part 52 moves freely along the Y-axis guide part 51.

The conveyance unit 58 moves along the conveyance path 50 while holding the substrate 10 to convey the substrate 10 . The conveying part 58 may also hold the substrate 10 through the frame. The conveying part 58 performs vacuum suction on the substrate 10, but it may also perform electrostatic suction on the substrate 10. The conveyance part 58 includes the Y-axis slide part 52 as a conveyance base, etc., and moves along the Y-axis direction. The conveying part 58 can move in the X-axis direction, the Z-axis direction, and the θ direction in addition to the Y-axis direction. In addition, the conveyance unit 58 has an inversion mechanism for inverting the substrate 10 up and down.

The conveyance part 58 may have a plurality of holding parts for holding the substrate 10 . The plurality of holding parts are arranged side by side with intervals in the Z-axis direction. The plurality of holding parts can be used in stages according to the processing stages of the substrate 10 .

The loading part 30 , the unloading part 40 , the alignment part 60 and the laser processing part 100 are provided adjacent to the conveyance path 50 when viewed from the vertical direction. For example, the longitudinal direction of the conveyance path 50 is the Y-axis direction. On the X-axis negative direction side of the conveyance path 50, a carry-in part 30 and a carry-out part 40 are provided. In addition, the alignment part 60 and the laser processing part 100 are provided on the X-axis positive direction side of the conveyance path 50 .

In addition, the arrangement or number of processing units such as the alignment unit 60 or the laser processing unit 100 is not limited to those shown in FIG. 2 and can be selected arbitrarily. In addition, a plurality of processing units can also be dispersed or integrated in any unit. Each processing unit will be described below.

The alignment unit 60 measures the center position of the substrate 10 and the crystal orientation of the substrate 10 (for example, the direction of the notch 19 ). For example, the alignment unit 60 has: a substrate holding unit that holds the substrate 10 from below; an imaging unit that photographs the substrate 10 held by the substrate holding unit; and a moving unit that causes the imaging unit to capture the imaging position of the substrate 10 Move. In addition, the crystal orientation of the substrate 10 can also be represented by an orientation plane instead of the notch 19 .

The laser processing unit 100 performs laser processing on the substrate 10 . For example, the laser processing unit 100 performs laser processing (so-called laser cutting) for dividing the substrate 10 into a plurality of wafers. The laser processing unit 100 irradiates the processing laser beam LB1 (see FIG. 6 ) to a point on the planned division line 13 (see FIG. 1 ), and moves the irradiation point on the planned division line 13 to process the substrate 10 Implement laser processing.

Next, a substrate processing method using the substrate processing system 1 configured as described above will be described with reference to FIG. 3 . FIG. 3 is a flowchart showing the substrate processing method of the first embodiment.

The substrate processing method shown in FIG. 3 includes a loading step S101, an alignment step S102, a laser processing step S103, and an unloading step S104. These steps are executed under the control of the control unit 20 .

In the loading step S101 , the transport unit 58 takes out the substrate 10 from the loading cassette 35 placed in the loading unit 30 , turns the taken-out substrate 10 upside down, and then transports it to the alignment unit 60 .

In the alignment step S102 , the alignment unit 60 measures the center position of the substrate 10 and the crystal orientation of the substrate 10 (for example, the direction of the notch 19 ). Based on the measurement results, the substrate 10 is positioned in the X-axis direction, the Y-axis direction, and the θ direction. The substrate 10 that has been positioned is transported from the alignment unit 60 to the laser processing unit 100 by the transport unit 58 .

In the laser processing step S103, the laser processing unit 100 performs laser processing on the substrate 10. The laser processing unit 100 irradiates the processing laser beam LB1 (see FIG. 6 ) to a point on the planned division line 13 (see FIG. 1 ), and moves the irradiation point on the planned division line 13 to perform the operation. Laser processing to divide the substrate 10 into a plurality of wafers.

In the unloading step S104 , the conveying unit 58 conveys the substrate 10 from the laser processing unit 100 to the unloading unit 40 , and the unloading unit 40 stores the substrate 10 inside the unloading cassette 45 . The unloading cassette 45 is carried out from the unloading part 40 to the outside.

FIG. 4 is a plan view showing the laser processing portion of the first embodiment. FIG. 4( a ) is a plan view showing a state during alignment processing of the laser processing section. FIG. 4( b ) is a plan view showing the state of the laser processing portion during laser processing. Fig. 5 is a front view showing the laser processing section of the first embodiment. Fig. 6 is a side view showing the processing head and the substrate holding portion of the first embodiment.

The laser processing part 100 includes a substrate holding part 110, an alignment part 120, a processing head 130, a processing head lifting part 135, a substrate moving part 140, and a control part 20. In addition, the control unit 20 is provided separately from the laser processing unit 100 in FIG. 2 , but may also be provided as a part of the laser processing unit 100.

The substrate holding part 110 holds the substrate 10 horizontally from below. As shown in FIG. 6 , the substrate 10 is placed on the top surface of the substrate holding portion 110 so that the first main surface 11 protected by the protective tape 14 faces downward. The substrate holding part 110 holds the substrate 10 via the protective tape 14 . For the substrate holding portion 110 , for example, a vacuum chuck is used, but an electrostatic chuck or the like may also be used.

The alignment unit 120 detects the planned division line 13 of the substrate 10 held by the substrate holding unit 110 (see FIG. 1 ). The planned division lines 13 of the substrate 10 are set on a plurality of cutting lines that are previously formed in a grid shape on the first main surface 11 of the substrate 10 .

The alignment unit 120 has, for example, an imaging unit 121 that captures an image of the substrate 10 held by the substrate holding unit 110 . In this embodiment, the imaging unit 121 cannot move in the horizontal direction relative to the fixed base 101, but may be movable in the horizontal direction relative to the fixed base 101. The imaging unit 121 is movable in the vertical direction relative to the fixed base 101 in order to adjust the height of the focus of the imaging unit 121 .

The imaging unit 121 is provided above the substrate holder 110 and photographs the dicing lines preliminarily formed on the bottom surface of the substrate 10 (for example, the first main surface 11 ) from above the substrate 10 held by the substrate holder 110 . At this time, an infrared camera that captures infrared images that penetrate the substrate 10 can be used as the imaging unit 121 .

The imaging unit 121 converts the photographed image of the substrate 10 into an electronic signal and sends it to the control unit 20 . The control unit 20 performs image processing on the image of the substrate 10 before laser processing captured by the imaging unit 121 to detect the position of the planned division line 13 of the substrate 10 . As for the detection method, a method of matching a pattern of grid-shaped dicing lanes previously formed on the first main surface 11 of the substrate 10 with a reference pattern is adopted, and the detection method of the substrate 10 is determined from a plurality of points on the outer periphery of the substrate 10 The center point and the orientation of the substrate 10 may be determined by a conventional method. The orientation of the substrate 10 is detected based on the position of the notch 19 (see FIG. 1 ) formed on the outer periphery of the substrate 10 . Orientation planes can also be used instead of notches 19 . Thereby, the control unit 20 can grasp the position of the planned dividing line 13 of the substrate 10 in the coordinate system fixed to the substrate holding unit 110 . In addition, image processing can also be performed simultaneously with image capture, or can be performed after image capture.

The alignment part 120 may also serve as an inspection part for detecting the laser processing results of the substrate 10 in order to reduce costs or reduce the installation area. The so-called laser processing results refer to whether there are any abnormalities in laser processing. Regarding whether there are abnormalities in laser processing, examples include whether the processing marks formed by irradiating the substrate 10 with the processing laser beam LB1 (see FIG. 6 ) are misaligned with the planned division line 13 , and whether there are cracks.

The imaging unit 121 photographs the processing marks formed by irradiating the substrate 10 with the processing laser beam LB1 (see FIG. 6 ). When the modified layer 15 is formed inside the substrate 10 , an infrared camera that captures infrared images penetrating the substrate 10 may be used as the imaging unit 121 .

The imaging unit 121 converts the captured image of the substrate 10 into an electronic signal and sends it to the control unit 20 . The control unit 20 performs image processing on the image of the laser-processed substrate 10 captured by the imaging unit 121 to detect the laser processing result of the substrate 10 . Image processing can be performed simultaneously with image capture or after image capture.

In addition, the alignment part 120 also serves as the inspection part in this embodiment, but it may not also serve as the inspection part. That is, the alignment part 120 and the inspection part may be provided separately. At this time, the inspection unit may be provided as a part of the laser processing unit 100 , or may be provided outside the laser processing unit 100 .

The processing head 130 has a housing 131 housing an optical system that irradiates the top surface (for example, the second main surface 12 ) of the substrate 10 with the processing laser beam LB1 from above. The processing head 130 is unable to move in the horizontal direction relative to the fixed table 101 in this embodiment, but may be movable in the horizontal direction relative to the fixed table 101 .

In this embodiment, the processing laser beam LB1 forms the modified layer 15 as a starting point for disconnection inside the substrate 10 as shown in FIG. 6 . When forming the modified layer 15 inside the substrate 10 , laser light penetrating to the substrate 10 is used. The modified layer 15 is formed, for example, by locally melting and solidifying the inside of the substrate 10 .

In addition, in this embodiment, the processing laser beam LB1 will form the modified layer 15 as a starting point for breaking inside the substrate 10 , but it may also form a laser processing groove on the top surface of the substrate 10 . The laser-processed groove may or may not penetrate the substrate 10 in the thickness direction. At this time, laser light having absorption characteristics with respect to the substrate 10 is used.

The processing head lifting part 135 moves the processing head 130 in the vertical direction relative to the fixed table 101 in order to adjust the distance between the processing head 130 and the substrate 10 . The processing head lifting part 135 is composed of, for example, a servo motor and a ball screw that converts the rotational motion of the servomotor into linear motion.

The substrate moving part 140 moves the substrate holding part 110 relative to the fixing table 101 when viewed from the Z-axis direction. The substrate moving part 140 moves the substrate holding part 110 in the X-axis direction, the Y-axis direction, and the θ direction. In addition, the substrate moving part 140 can also move the substrate holding part 110 in the Z-axis direction.

The substrate moving part 140 has a Y-axis guide part 142 extending in the Y-axis direction, and a Y-axis sliding part 143 that moves along the Y-axis guide part 142. As a drive source for moving the Y-axis slide portion 143 in the Y-axis direction, a servo motor or the like is used. The rotational motion of the servo motor is converted into linear motion of the Y-axis sliding portion 143 using a motion conversion mechanism such as a ball screw. In addition, the substrate moving part 140 has an X-axis guide part 144 extending in the X-axis direction, and an X-axis sliding part 145 that moves along the X-axis guide part 144. As a drive source for moving the X-axis slide part 145 in the X-axis direction, a servo motor or the like is used. The rotational motion of the servo motor is converted into linear motion of the X-axis sliding part 145 using a motion conversion mechanism such as a ball screw. Furthermore, the substrate moving unit 140 has a turntable 146 that moves in the θ direction (see FIG. 5 ). As a drive source for moving the turntable 146 in the θ direction, a servo motor or the like is used.

For example, the Y-axis guide 142 is fixed to the fixed base 101 . The Y-axis guide part 142 is provided across the alignment part 120 and the processing head 130 when viewed from the Z-axis direction. The X-axis guide 144 is fixed to the Y-axis slide 143 that moves along the Y-axis guide 142 . The rotary table 146 is rotatably provided on the X-axis sliding part 145 that moves along the X-axis guide part 144 . The substrate holding part 110 is fixed to the turntable 146 .

7 is a plan view showing the moving path of the irradiation point of the processing laser light on the top surface of the substrate and the extended surface extending horizontally from the top surface of the substrate in the first embodiment.

The control unit 20 uses the substrate moving unit 140 to move the substrate holding unit 110 and irradiates the processing laser beam LB1 to the point SP (hereinafter also referred to as the “processing start point SP”) of the planned division line 13 detected by the alignment unit 120 .

Thereafter, the control unit 20 moves the substrate holding unit 110 in the X-axis direction so that the irradiation point P1 (hereinafter also referred to as "processing") of the processing laser light LB1 on the top surface of the substrate 10 held by the substrate holding unit 110 Use the irradiation point P1") to move in the X-axis direction. Thereby, processing marks extending in the X-axis direction are formed. The Y-axis direction position or the θ-direction position of the substrate holding portion 110 is controlled in advance so that the processing mark coincides with the planned division line 13 .

Thereafter, the control unit 20 repeatedly executes the two operations of "moving the substrate holding part 110 in the Y-axis direction" and "moving the substrate holding part 110 in the X-axis direction" to move the processing irradiation point P1 to the division point. A point EP on the planned line 13 (hereinafter also referred to as "processing end point EP"). Thereby, a plurality of processing marks extending in the X-axis direction are formed at intervals in the Y-axis direction.

In addition, the machining marks extending in the X-axis direction may be dotted or linear. The dotted line-shaped processing marks are formed using the processing laser light LB1 emitted by pulse oscillation. The linear machining marks are formed using the machining laser light LB1 emitted by continuous wave oscillation.

Thereafter, the control unit 20 rotates the substrate holding unit 110 by 90° in the θ direction, and then forms a plurality of processing marks extending in the X-axis direction at intervals in the Y-axis direction. Thereby, processing marks can be formed along the grid-shaped planned dividing lines 13 set on the substrate 10 held by the substrate holding portion 110 .

In addition, in this embodiment, as shown in FIG. 4(b) and FIG. 7 , a plurality of processing marks extending in the X-axis direction are formed at intervals in the Y-axis direction. However, the processing marks may also be formed in the X-axis direction at intervals. A plurality of processing marks extending in the Y-axis direction are formed at intervals in the direction.

In addition, in this embodiment, the substrate moving part 140 is used as the irradiation point moving part for moving the processing irradiation point P1, but the present invention is not limited to this. The movement of the processing irradiation point P1 can be realized by at least one of movement of the substrate 10 and movement of the processing head 130 .

FIG. 8 is a diagram showing the path of the processing laser light and the path of the measuring laser light in the first embodiment. As shown in FIG. 8 , the laser processing unit 100 has a processing laser oscillation unit 150 that oscillates and emits the processing laser beam LB1 for processing the substrate 10 , and the processing laser beam LB1 is emitted from the processing laser beam LB1 . The light collecting portion 152 is concentrated downward from above the point P1. The processing laser oscillation unit 150 is, for example, provided outside the frame 131 of the processing head 130 and is fixed to the fixing table 101 . On the other hand, the light collecting unit 152 is accommodated in the frame 131 of the processing head 130 and moves in the vertical direction with the frame 131 relative to the fixed table 101 .

The processing laser oscillation unit 150 oscillates, for example, the processing laser light LB1 having a wavelength that is transparent to the substrate 10 . As the processing laser oscillator 150, for example, a YVO ₄ pulse laser oscillator or a YAG pulse laser oscillator is used. The wavelength of the processing laser light LB1 is, for example, 1064 nm. In order to change the wavelength of the processing laser light LB1, a plurality of processing laser oscillation units 150 may be prepared and installed interchangeably. The processing laser light LB1 oscillated and emitted by the processing laser oscillation unit 150 passes through the dichroic mirror 154 , for example, and then is redirected by the direction conversion mirror 156 and guided to the light collecting unit 152 .

The light collecting part 152 includes a light collecting lens. The condensing lens concentrates the processing laser light LB1 oscillated and emitted by the processing laser oscillator 150 into, for example, the substrate 10 . Thereby, the modified layer 15 is formed inside the substrate 10 (see FIG. 6 ). The light collecting unit 152 is movable in the vertical direction inside the frame 131 of the processing head 130 .

As shown in FIG. 8 , the laser processing unit 100 has a light collecting unit moving unit 158 inside the frame 131 for moving the light collecting unit 152 in the vertical direction. The light collecting unit moving unit 158 is not particularly limited. For example, a high-resolution piezoelectric actuator may be used. A piezoelectric actuator includes a piezoelectric element that expands and contracts in the vertical direction in response to an applied voltage. The light collecting unit moving unit 158 moves, for example, the light collecting unit box 153 that houses the light collecting unit 152 in the vertical direction, so that the light collecting unit 152 moves in the vertical direction.

As shown in FIG. 8 , the laser processing unit 100 includes a height measurement unit 160 that measures the vertical position of the processing irradiation point P1. The height measurement unit 160 sends a signal indicating the measurement result to the control unit 20 . The control unit 20 controls the vertical position of the light collecting unit 152 based on the vertical position of the processing irradiation point P1 while moving the processing irradiation point P1. Thereby, as shown in FIG. 6 , when the top surface of the substrate 10 has undulations, the modified layer 15 can be formed at a fixed depth from the top surface of the substrate 10 . In addition, the undulations on the top surface of the substrate 10 are caused by the difference in thickness of the film layer 18 in FIG. 6 , but may also be caused by the difference in thickness of the substrate body 17 .

The height measuring unit 160 irradiates the top surface of the substrate 10 with the measurement laser beam LB2 and receives the reflected light of the measurement laser beam LB2 reflected by the top surface of the substrate 10 to measure the vertical direction of the processing irradiation point P1 Location. The measurement laser light LB2 has a different wavelength from the processing laser light LB1, and has the same wavelength as the processing laser light LB1 from the dichroic mirror 154 provided in the middle of the path of the processing laser light LB1 to the top surface of the substrate 10 Same path as LB1. That is, on the top surface of the substrate 10, the processing irradiation point P1 overlaps with the irradiation point P2 of the measurement laser beam LB2 (hereinafter also referred to as the "measurement irradiation point P2").

The height measuring unit 160 has a measuring laser oscillation unit 162 . The measurement laser oscillation unit 162 oscillates and emits the measurement laser light LB2 having a wavelength that is reflective with respect to the substrate 10 . As the measurement laser oscillator 162, for example, a He—Ne pulse laser oscillator is used. The wavelength of the measuring laser light LB2 is, for example, 635 nm. The measurement laser light LB2 oscillated and emitted by the measurement laser oscillation unit 162 passes through, for example, the beam splitter 164 and is reflected by the dichroic mirror 154. Then, the direction is changed by the direction conversion mirror 156 and guided to the light collecting unit 152. .

In addition, in this embodiment, the dichroic mirror 154 allows the processing laser light LB1 to pass through and reflects the measurement laser light LB2 at the same time, but the reverse can also be done. That is, the dichroic mirror 154 may reflect the processing laser light LB1 and simultaneously allow the measurement laser light LB2 to pass therethrough. In any case, it is sufficient that the processing irradiation point P1 and the measurement irradiation point P2 overlap on the top surface of the substrate 10 .

The measurement laser light LB2 is reflected by the top surface of the substrate 10 after being irradiated onto the top surface of the substrate 10 . The reflected light passes through the light collecting unit 152 , is redirected by the direction converting mirror 156 , is reflected by the dichroic mirror 154 and the beam splitter 164 , passes through the bandpass filter 166 , and is then guided to the reflected light receiving unit 170 . The bandpass filter 166 passes only light having the same wavelength (for example, 635 nm) as the measurement laser light LB2.

The reflected light receiving unit 170 has a beam splitter 171 that divides the reflected light that has passed through the bandpass filter 166 into a first light receiving path 172 and a second light receiving path 175 . The first light receiving path 172 is provided with a light collecting lens 173 that concentrates 100% of the scattered reflected light, and a first light receiving element 174 that receives the reflected light concentrated by the light collecting lens 173 . The first light-receiving element 174 sends a voltage signal corresponding to the intensity of the received reflected light to the control unit 20 .

On the other hand, the second light-receiving path 175 is provided with the second light-receiving element 176 that receives the split reflected light, and the light-receiving range limiting portion 177 that limits the light-receiving range of the reflected light received by the second light-receiving element 176 . The light-receiving range limiting unit 177 has, for example, a cylindrical lens 178 that concentrates the reflected light that has been split into one dimension, and a one-dimensional mask that limits the reflected light that is concentrated in one dimension by the cylindrical lens 178 to a unit length. 179. The reflected light passing through the one-dimensional mask 179 is received by the second light-receiving element 176 , and the second light-receiving element 176 sends a voltage signal corresponding to the intensity of the received reflected light to the control unit 20 .

9 is a diagram showing the relationship between the vertical position of the irradiation point of the measurement laser light on the top surface of the substrate and the size of the irradiation point of the measurement laser light on the top surface of the substrate in the first embodiment. The measurement laser light LB2 is concentrated on the substrate 10 by the light collecting part 152 . Therefore, the measurement irradiation point P2 corresponding to the size of the distance L between the light collecting part 152 and the substrate 10 is formed on the top surface of the substrate 10 . The reflected light reflected at the measurement irradiation point P2 is divided into a first light receiving path 172 and a second light receiving path 175 by the beam splitter 171 .

All of the reflected light divided into the first light receiving path 172 is collected by the collecting lens 173 to the first light receiving element 174 . Therefore, the intensity of the reflected light received by the first light-receiving element 174 is constant regardless of the size of the measurement irradiation point P2. Therefore, the voltage V1 output from the first light-receiving element 174 is constant regardless of the vertical position of the measurement irradiation point P2.

On the other hand, the reflected light divided into the second light receiving path 175 is concentrated in one dimension by the cylindrical lens 178 . At this time, the larger the size of the measurement irradiation point P2 is, the longer the length of the reflected light concentrated in one dimension is. Then, the reflected light concentrated in one dimension is limited to a predetermined unit length by the one-dimensional mask 179 and then is received by the second light-receiving element 176 . Therefore, the larger the size of the measurement irradiation point P2 is, the smaller the intensity of the reflected light received by the second light-receiving element 176 is. In this way, the intensity of the reflected light received by the second light-receiving element 176 changes according to the size of the measurement irradiation point P2. Therefore, the voltage V2 output from the second light-receiving element 176 changes according to the vertical position of the measurement irradiation point P2.

The control unit 20 determines the vertical position of the measurement irradiation point P2 based on the voltage ratio V1/V2 of the voltage V1 output by the first light-receiving element 174 and the voltage V2 output by the second light-receiving element 176 . When determining the vertical direction position of the measurement irradiation point P2, a graph or the like showing the relationship between the vertical direction position of the measurement irradiation point P2 and the voltage ratio V1/V2 is used. This graph can be prepared through preliminary experiments and the like, and can be stored in the recording medium 22 . Since the measurement irradiation point P2 and the processing irradiation point P1 overlap on the top surface of the substrate 10, the vertical position of the processing irradiation point P1 can be obtained by determining the vertical position of the measurement irradiation point P2.

In addition, all of the reflected light distributed to the first light receiving path 172 is received by the first light receiving element 174 , whereas only part of the reflected light distributed to the second light receiving path 175 is received by the second light receiving element 176 . Therefore, when the intensity of the reflected light distributed to the first light receiving path 172 is the same as the intensity of the reflected light distributed to the second light receiving path 175 , the voltage V2 output by the second light receiving element 176 will be higher than that of the first light receiving element 174 The output voltage V1 is smaller.

In addition, the top surface of the reflection measurement laser beam LB2 of the substrate 10 may be formed of a film layer 18 (see FIG. 6 ) such as a silicon oxide film or a silicon nitride film. The substrate 10 , as shown in FIG. 6 , includes a substrate body 17 such as a silicon wafer, and a film layer 18 formed on the surface of the substrate body 17 . The film layer 18 may have a single-layer structure or a plurality of layer structures. Since the film layer 18 is formed unintentionally during the process of forming the device, the thickness of the film layer 18 is different. This difference may occur within one substrate 10 or between a plurality of substrates 10 .

10 is a diagram schematically showing the relationship between the material and film thickness of the film layer forming the top surface of the substrate in the first embodiment and the reflectivity of the measurement laser light on the top surface of the substrate. In FIG. 10 , the horizontal axis represents the film thickness of the silicon oxide film constituting the film layer 18 , and the vertical axis represents the film thickness of the silicon nitride film constituting the film layer 18 . The film layer 18 may include both a silicon oxide film and a silicon nitride film, or may include any one of them.

As shown in FIG. 10 , when the thickness of the silicon nitride film is the same, as the thickness of the silicon oxide film becomes larger, the reflectance R of the measurement laser light LB2 on the top surface of the substrate 10 repeatedly becomes stronger or smaller. weak. Similarly, when the thickness of the silicon oxide film is the same, as the thickness of the silicon nitride film becomes larger, the reflectance R of the measurement laser light LB2 on the top surface of the substrate 10 repeatedly becomes stronger or weaker.

In this way, the reflectance R of the measurement laser light LB2 on the top surface of the substrate 10 changes depending on the material and film thickness of the film layer 18 forming the top surface of the substrate 10. Therefore, the reflection received by the reflected light receiver 170 The intensity of light will vary. Therefore, when the output of the measurement laser oscillation unit 162 is insufficient, the voltage V2 indicating the intensity of the reflected light received by the second light-receiving element 176 may become lower than the threshold V2 ₀ (for example, 0.3V). The threshold value V2 ₀ is a lower limit value used to measure the vertical position of the measurement irradiation point P2.

In addition, in this embodiment, a confocal laser displacement meter is used as the height measuring unit 160, but the measurement method of the laser displacement meter is not particularly limited. The measurement method of the laser displacement meter may be, for example, any of a common focus method, a trigonometric distance measurement method, a time of flight method, and an interference method. Regardless of the measurement method of the laser displacement meter, the laser displacement meter has a laser oscillator and a light-receiving element. The laser light oscillated by the laser oscillator is reflected by the top surface of the substrate 10, and the reflected light is reflected by the light-receiving element. received. Therefore, when the output of the laser oscillator is insufficient, the intensity of the reflected light received by the light-receiving element may be lower than the lower limit value.

FIG. 11 schematically illustrates the relationship between the output of the measurement laser oscillation unit, the reflectivity of the measurement laser light on the top surface of the substrate, and the intensity of the reflected light received by the second light-receiving element in the first embodiment. Schema of representation. The greater the output W of the measurement laser oscillation unit 162, the stronger the intensity of the measurement laser light LB2 emitted by the measurement laser oscillation unit 162, and the greater the irradiation intensity of the measurement laser light LB2 on the top surface of the substrate 10. Strong.

As shown in FIG. 11 , when the output W of the measurement laser oscillation unit 162 is fixed, the voltage V2 indicating the intensity of the reflected light received by the second light-receiving element 176 is in contact with the measurement laser on the top surface of the substrate 10 . The reflectance R of the radiation line LB2 is proportional to the reflectance R. In addition, when the reflectance R of the measurement laser light LB2 on the top surface of the substrate 10 is fixed, the voltage V2 indicating the intensity of the reflected light received by the second light receiving element 176 is different from the voltage V2 of the measurement laser oscillation unit 162 . The output is proportional to W.

Therefore, as shown in FIG. 11 , the reflectance R corresponding to the threshold value V2 ₀ (hereinafter also referred to as the “limit reflectivity”) is inversely proportional to the output W. The limit reflectance is the lower limit value used to measure the reflectance R at the vertical position of the measurement irradiation point P2. When the output W is increased to 2 times, the limit reflectivity becomes 1/2. In addition, when the output W is increased to 5 times, the limit reflectivity becomes 1/5. In this way, by increasing the output W, the boundary reflectivity can be reduced.

Therefore, the control unit 20 of this embodiment controls the output W based on the voltage V2 so that the voltage V2 does not fall below the threshold value _V20 . Unlike the state where the output W is always fixed at the maximum output, since the output W is changed according to the voltage V2, the power consumption of the measurement laser oscillation unit 162 can be suppressed, and the heat generation caused by the power consumption can be suppressed. . Therefore, the cooling mechanism for cooling the measurement laser oscillation unit 162 can be downsized. There may even be no need for a cooling mechanism. Therefore, a small laser displacement meter can be used to measure the vertical position of the measurement irradiation point P2, and can also measure the vertical position of the processing irradiation point P1.

In addition, the control unit 20 in this embodiment controls the output W according to the voltage V2 so that the voltage V2 does not fall below the threshold _V20 , but the present invention is not limited to this. For example, when the voltage V1 is smaller than the voltage V2, the control unit 20 may also control the output W according to the voltage V1 so that the voltage V1 does not fall below the threshold _V10 . The threshold V1 ₀ is a lower limit value (for example, 0.3 V) used to measure the vertical position of the measurement irradiation point P2. The same applies to the processing shown in FIGS. 12 , 13 , 15 and 17 .

FIG. 12 is a flowchart showing a first example of processing by the control unit in the first embodiment. The process shown in FIG. 12 makes the film thickness (and thus the reflectivity) of the film layer 18 non-uniform within the surface of one substrate 10 . In addition, the process shown in FIG. 12 can also be used in a state where the film thickness of the film layer 18 is uniform throughout the surface of one substrate 10 and is non-uniform among a plurality of substrates 10 . The processing after step S201 shown in FIG. 12 is executed after the alignment unit 120 detects the planned division line 13 .

First, the control unit 20 performs vertical position alignment of the processing head 130 (step S201). Thereby, as shown in FIG. 6 , the frame 131 of the processing head 130 is arranged at a predetermined height from the substrate holding part 110 .

Next, the control unit 20 causes the processing irradiation point P1 to start moving (step S202). Specifically, the control unit 20 causes the processing irradiation point P1 to start moving from the processing start point SP shown in FIG. 7 to the processing end point EP.

Next, the control unit 20 controls the vertical position of the light collecting unit 152 based on the voltage ratio V1/V2 indicating the vertical position of the processing irradiation point P1, and simultaneously controls the vertical position of the light collecting unit 152 based on the voltage ratio V1/V2 indicating the intensity of the reflected light received by the second light receiving element 176. voltage V2 to control the output W of the measurement laser oscillation unit 162 (step S203). Here, the vertical position of the light collecting portion 152 is controlled so that the modified layer 15 is formed at a certain depth from the top surface of the substrate 10 . The light collecting unit 152 moves in the vertical direction inside the frame 131 of the processing head 130 . In addition, the output W of the measurement laser oscillation unit 162 is controlled so that the voltage V2 does not fall below the threshold V2 ₀ . Thereby, the vertical position of the processing irradiation point P1 can be measured. The measurement results are used to control the vertical position of the light collecting unit 152 .

Next, after the processing irradiation point P1 reaches the processing end point EP, the control unit 20 ends the movement of the processing irradiation point P1 (step S204), and ends this processing. Thereby, a plurality of processing marks extending in the X-axis direction are formed at intervals in the Y-axis direction.

Thereafter, the control unit 20 rotates the substrate holding unit 110 by 90° in the θ direction, and then forms a plurality of processing marks extending in the X-axis direction at intervals in the Y-axis direction. Thereby, processing marks can be formed along the grid-shaped planned division lines 13 set on the substrate 10 .

As described above, according to the processing shown in FIG. 12 , the voltage V2 indicating the intensity of the reflected light received by the second light-receiving element 176 is monitored while moving the processing irradiation point P1, and based on the monitoring result The output W of the measurement laser oscillation unit 162 is controlled. This can reliably prevent the voltage V2 from falling below the threshold V2 ₀ when the film thickness of the film layer 18 (and thus the reflectance R) changes corresponding to the position of the processing irradiation point P1.

When the film thickness of the film layer 18 (and thus the reflectance R) is not uniform within the surface of one substrate 10, the control unit 20 performs measurement while processing the one substrate 10 with the processing laser beam LB1. The output of the laser oscillator 162 is changed. This output change is performed based on the voltage V2 indicating the intensity of the reflected light received by the second light-receiving element 176 . Then, while the substrate 10 is being processed with the processing laser beam LB1, the voltage V2 is measured while moving the measurement irradiation point P2 on the planned dividing line 13 . Either output increase or output decrease can be implemented, or both can be implemented. In addition, the number of output changes only needs to be one or more. Although the output W can be changed while one planned division line 13 is being processed, the output W can be maintained constant. When processing one planned dividing line 13 and when processing the other planned dividing line 13 , different outputs W can be set. During processing of one substrate 10, unlike the state where the output W is always fixed at the maximum output, since the output W is changed according to the voltage V2, the power consumption of the measurement laser oscillation unit 162 can be suppressed. Furthermore, heat generation caused by the power consumption can be suppressed. Therefore, the cooling mechanism for cooling the measurement laser oscillation unit 162 can be downsized. There may even be no need for a cooling mechanism. Therefore, a small laser displacement meter can be used to measure the vertical position of the measurement irradiation point P2, and can also measure the vertical position of the processing irradiation point P1.

FIG. 13 is a flowchart showing a second example of processing by the control unit in the first embodiment. The processing shown in FIG. 13 is mainly used when the film thickness (and even the reflectance R) of the film layer 18 is not uniform within the surface of one substrate 10 . In addition, the process shown in FIG. 13 can also be used in a state where the film thickness of the film layer 18 is uniform throughout the surface of one substrate 10 and is non-uniform among a plurality of substrates 10 . The processing after step S301 shown in FIG. 13 is executed after the alignment unit 120 detects the planned division line 13 .

First, the control unit 20 performs vertical position alignment of the processing head 130 (step S301). Thereby, as shown in FIG. 6 , the frame 131 of the processing head 130 is arranged at a predetermined height from the substrate holding part 110 .

Next, before processing the substrate 10 with the processing laser beam LB1, the control unit 20 measures the time when the measurement laser beam LB2 is irradiated to the top surface of the substrate 10 and the measurement irradiation point P2 is moved on the planned division line 13. The voltage V2 represents the intensity of the reflected light received by the second light-receiving element 176 (step S302). In addition, in step S302, the top surface of the substrate 10 is not irradiated with the processing laser beam LB1.

Next, the control unit 20 sets the output W of the measurement laser oscillation unit 162 in step S305 described below based on the measured voltage V2 (step S303). The output W is set in step S305 described below so that the voltage V2 does not fall below the threshold _V20 .

Next, the control unit 20 starts the movement of the processing irradiation point P1 of the processing laser beam LB1 (step S304). Specifically, the control unit 20 causes the processing irradiation point P1 to start moving from the processing start point SP shown in FIG. 7 to the processing end point EP.

Next, the control unit 20 controls the vertical position of the light collecting unit 152 based on the voltage ratio V1/V2 indicating the vertical position of the processing irradiation point P1 (step S305). Here, the vertical position of the light collecting portion 152 is controlled so that the modified layer 15 is formed at a certain depth from the top surface of the substrate 10 . The light collecting unit 152 moves in the vertical direction inside the frame 131 of the processing head 130 . In addition, the output W of the measurement laser oscillation unit 162 is controlled to the setting value set in step S303. Thereby, the voltage V2 can be prevented from falling below the threshold V2 ₀ and the vertical position of the processing irradiation point P1 can be measured. The measurement results are used to control the vertical position of the light collecting unit 152 .

Next, after the processing irradiation point P1 reaches the processing end point EP, the control unit 20 ends the movement of the processing irradiation point P1 (step S306), and ends this processing. Thereby, a plurality of processing marks extending in the X-axis direction are formed at intervals in the Y-axis direction.

Thereafter, the control unit 20 rotates the substrate holding unit 110 by 90° in the θ direction, and then forms a plurality of processing marks extending in the X-axis direction at intervals in the Y-axis direction. Thereby, processing marks can be formed along the grid-shaped planned division lines 13 set on the substrate 10 .

As described above, according to the processing shown in FIG. 13 , the reflected light received by the second light-receiving element 176 is measured based on the measurement laser beam LB2 on the top surface of the substrate 10 before processing. The intensity voltage V2 sets the output W of the measurement laser oscillator 162 during substrate processing. During substrate processing, this means that the processing irradiation point P1 is instructed to move on the planned division line 13 of the substrate 10 . Since the output W during substrate processing is set before substrate processing, the processing load of the control unit 20 during substrate processing can be reduced, thereby reducing the processing load of the control unit 20 during substrate processing.

When the film thickness of the film layer 18 (and thus the reflectance R) is not uniform within the surface of one substrate 10, the control unit 20 performs measurement while processing the one substrate 10 with the processing laser beam LB1. The output of the laser oscillator 162 is changed. This output change is performed based on the voltage V2 indicating the intensity of the reflected light received by the second light-receiving element 176 . Then, before processing the substrate 10 with the processing laser beam LB1, the voltage V2 is measured while moving the measurement irradiation point P2 on the planned division line 13. Either output increase or output decrease can be implemented, or both can be implemented. In addition, the number of output changes only needs to be one or more. Although the output W can be changed while one planned division line 13 is being processed, the output W can be maintained constant. When processing one planned dividing line 13 and when processing the other planned dividing line 13 , different outputs W can be set. During processing of one substrate 10, unlike the state where the output W is always fixed at the maximum output, since the output W is changed in response to the voltage V2, the power consumption of the measurement laser oscillation unit 162 can be suppressed. Furthermore, heat generation caused by the power consumption can be suppressed. Therefore, the cooling mechanism for cooling the measurement laser oscillation unit 162 can be downsized. There may even be no need for a cooling mechanism. Therefore, a small laser displacement meter can be used to measure the vertical position of the measurement irradiation point P2, and can also measure the vertical position of the processing irradiation point P1.

In addition, the process shown in FIG. 13 can also be used in a case where the film thickness (and therefore the reflectance R) of the film layer 18 is uniform within the entire surface of one substrate 10 and is non-uniform among a plurality of substrates 10 . . At this time, in step S302, the measurement irradiation point P2 does not need to move on the planned division line 13. Since the film thickness of all the film layers 18 is uniform within the surface of the substrate 10 , the voltage V2 indicating the reflected light intensity can also be measured at only one point within the surface of the substrate 10 . This can shorten the measurement time of voltage V2. In addition, when the film thickness of all the film layers 18 is uniform within the surface of the substrate 10 , the voltage V2 indicating the intensity of the reflected light may be measured at multiple points within the surface of the substrate 10 . It can be confirmed again whether the film thickness of the film layer 18 is uniform. Although the output W can be changed while one substrate 10 is being processed, the output W can be maintained constant. When one substrate 10 is processed and when another substrate 10 is processed, the output W can be set to be different.

Fig. 14 is a front view showing the laser processing section of the second embodiment. As shown in FIG. 14 , the alignment unit 120A of this embodiment, in addition to the imaging unit 121 , further has an inspection laser light LB2′ reflected by the top surface (for example, the second main surface 12 ) of the substrate 10 . The reflectance measuring unit 122 of the reflectivity. The inspection laser light LB2' has the same wavelength as the measurement laser light LB2, so the reflectance R of the inspection laser light LB2' is equal to the reflectance R of the measurement laser light LB2. Hereinafter, the differences between this embodiment and the above-described first embodiment will be mainly described.

The reflectance measuring unit 122 includes a laser oscillator that oscillates and emits the inspection laser light LB2′, and a light receiving element that receives the reflected light of the inspection laser light LB2′ reflected by the top surface of the substrate 10. The light-receiving element sends a voltage signal corresponding to the intensity of the received reflected light (that is, the reflectance) to the control unit 20 .

The control unit 20 sets the output W of the measurement laser oscillation unit 162 when the processing irradiation point P1 moves on the planned division line 13 of the substrate 10 based on the reflectance measured by the reflectance measurement unit 122 . The output W is set so that the voltage V2 does not fall below the threshold value V2 ₀ during substrate processing, and is set so as to correspond to the position of the processing irradiation point P1 on the planned division line 13 .

FIG. 15 is a flowchart showing the processing of the control unit in the second embodiment. The processing shown in FIG. 15 causes the film thickness (and thus the reflectance) of the film layer 18 to be non-uniform within the surface of one substrate 10 . In addition, the process shown in FIG. 15 can also be used in a state where the film thickness of the film layer 18 is uniform within the entire surface of one substrate 10 and is non-uniform among a plurality of substrates 10 . The processing after step S401 shown in FIG. 15 starts, for example, when the transport unit 58 places the substrate 10 on the substrate holding unit 110 .

First, the control unit 20 uses the reflectance measurement unit 122 to measure the reflectance of the inspection laser light LB2′ reflected by the top surface of the substrate 10 (step S401). For example, the control unit 20 uses the substrate moving unit 140 to move the irradiation point P2′ (hereinafter also referred to as the “inspection irradiation point P2′”) of the inspection laser light LB2′ on the top surface of the substrate 10 using reflection. The rate measurement unit 122 measures the reflectance of the inspection laser light LB2′. The inspection irradiation point P2' moves on the planned dividing line 13, and the reflectivity of the inspection laser light LB2' is memorized so as to correspond to the position of the inspection irradiation point P2' on the planned dividing line 13. The reflectance of the inspection laser light LB2´ is equal to the reflectance of the measurement laser light LB2.

Next, the control unit 20 sets the output W of the measurement laser oscillator unit 162 during substrate processing based on the reflectance measured by the reflectance measurement unit 122 (step S402). The output W is set so that the voltage V2 does not fall below the threshold value V2 ₀ during substrate processing, and is set so as to correspond to the position of the processing irradiation point P1 on the planned division line 13 .

Next, the control unit 20 performs vertical position alignment of the processing head 130 (step S403). Thereby, as shown in FIG. 6 , the frame 131 of the processing head 130 is arranged at a predetermined height from the substrate holding part 110 .

Next, the control unit 20 causes the processing irradiation point P1 to start moving (step S404). Specifically, the control unit 20 causes the processing irradiation point P1 to start moving from the processing start point SP shown in FIG. 7 to the processing end point EP.

Next, the control unit 20 controls the vertical position of the light collecting unit 152 based on the voltage ratio V1/V2 indicating the vertical position of the processing irradiation point P1 (step S405). At this time, the output W of the measurement laser oscillation unit 162 is controlled by the setting in step S402 described above. Therefore, the voltage V2 can be prevented from falling below the threshold V2 ₀ during substrate processing.

Next, after the processing irradiation point P1 reaches the processing end point EP, the control unit 20 ends the movement of the processing irradiation point P1 (step S406), and ends this processing. Thereby, a plurality of processing marks extending in the X-axis direction are formed at intervals in the Y-axis direction.

Thereafter, the control unit 20 rotates the substrate holding unit 110 by 90° in the θ direction, and then forms a plurality of processing marks extending in the X-axis direction at intervals in the Y-axis direction. Thereby, processing marks can be formed along the grid-shaped planned division lines 13 set on the substrate 10 .

As described above, according to the process shown in FIG. 15 , the reflectance of the inspection laser light LB2′ reflected by the top surface of the substrate 10 is measured. The inspection laser light LB2' has the same wavelength as the measurement laser light LB2, and the reflectance R of the inspection laser light LB2' is equal to the reflectance R of the measurement laser light LB2. Based on the measurement result of the reflectance R, the output W of the measurement laser oscillator 162 during substrate processing is set. Since the output W during substrate processing can be set before substrate processing, the processing load of the control unit 20 during substrate processing can be reduced, thereby reducing the processing load of the control unit 20 during substrate processing.

When the film thickness of the film layer 18 (and thus the reflectance R) is not uniform within the surface of one substrate 10, the control unit 20 performs measurement while processing the one substrate 10 with the processing laser beam LB1. The output of the laser oscillator 162 is changed. This output change is performed based on the reflectance measured by the reflectance measuring unit 122 . Either output increase or output decrease can be implemented, or both can be implemented. In addition, the number of output changes only needs to be one or more. Although the output W can be changed while one planned division line 13 is being processed, the output W can be maintained constant. When processing one planned dividing line 13 and when processing the other planned dividing line 13 , different outputs W can be set. During processing of one substrate 10, unlike the state where the output W is always fixed at the maximum output, since the output W is changed in response to the voltage V2, the power consumption of the measurement laser oscillation unit 162 can be suppressed. Furthermore, heat generation caused by the power consumption can be suppressed. Therefore, the cooling mechanism for cooling the measurement laser oscillation unit 162 can be downsized. There may even be no need for a cooling mechanism. Therefore, a small laser displacement meter can be used to measure the vertical position of the measurement irradiation point P2, and can also measure the vertical position of the processing irradiation point P1.

When the thickness of the film layer 18 (and therefore the reflectance R) is uniform within the entire surface of one substrate 10 and is non-uniform among a plurality of substrates 10 , the control unit 20 uses the processing laser light LB1 to While the plurality of substrates 10 are being processed, the output of the measurement laser oscillator 162 is changed. This output change is performed based on the reflectance measured by the reflectance measuring unit 122 . Either output increase or output decrease can be implemented, or both can be implemented. In addition, the number of output changes only needs to be one or more. Although the output W can be changed while one substrate 10 is being processed, the output W can be maintained constant. When one substrate 10 is processed and when another substrate 10 is processed, the output W can be set to be different. During the processing of a plurality of substrates 10, unlike the state where the output W is always fixed at the maximum output, since the output W is changed according to the voltage V2, the power consumption of the measurement laser oscillation unit 162 can be suppressed. Furthermore, heat generation caused by the power consumption can be suppressed. Therefore, the cooling mechanism for cooling the measurement laser oscillation unit 162 can be downsized. There may even be no need for a cooling mechanism. Therefore, a small laser displacement meter can be used to measure the vertical position of the measurement irradiation point P2, and can also measure the vertical position of the processing irradiation point P1.

In addition, in this embodiment, the reflectance measurement part 122 is provided in a part of the laser processing part 100 (that is, the alignment part 120), but it may also be provided in a part that is different from the laser processing part 100. The alignment part 60 may also be provided in both. In order to improve productivity, the measurement of the reflectance R in the alignment section 60 can be performed simultaneously with the detection of the center position of the substrate 10 and the crystal orientation of the substrate 10 .

As mentioned above, the alignment unit 60 has a substrate holding part that holds the substrate 10 from below, an imaging part that photographs the substrate 10 held by the substrate holding part, and a movement that moves the imaging part to the imaging position of the substrate 10 department. The substrate holding part, the imaging part, and the moving part provided in the alignment part 60 are configured in the same manner as the substrate holding part 110, the imaging part 121, and the substrate moving part 140 provided in the laser processing part 100, so the drawings are omitted.

FIG. 16 is a diagram showing the components of the control unit in the third embodiment in functional blocks. Each functional block shown in FIG. 16 is a conceptual functional block, which may not be constructed in the manner of a physical structure diagram. A structure can be constructed in which all or part of each functional block is functionally or physically dispersed and integrated in any unit. All or any part of each processing function performed in each functional block can be realized by a program executed by the CPU, or can be realized by hardware set according to wiring logic. Hereinafter, the differences between this embodiment and the above-described first embodiment will be mainly described.

As shown in FIG. 16 , the control unit 20 is connected to the data server 2 through a network such as a LAN (Local Area Network) or an Internet line. This connection may be a wired connection or a wireless connection. The data server 2 is provided in a factory where the substrate processing system 1 is installed, etc., and sends various data to the substrate processing system 1 . For example, in the data server 2, the identification information of the substrate 10 and the information about the material and film thickness of the film layer 18 forming the top surface of the substrate 10 (for example, the second main surface 12) are stored in a mutually corresponding manner (hereinafter also referred to as Referred to as "layer data").

The film thickness of the film layer 18 is measured at least on each of the plurality of planned dividing lines 13 , and the measured values are stored in the data server 2 . The film thickness of the film layer 18 will continuously change along the plurality of planned dividing lines 13 . Therefore, the film thickness of the film layer 18 is stored in the data server 2 in a manner corresponding to the position within the surface of the substrate 10 . In addition, when the film layer 18 has a plural-layer structure, the film thickness of each film layer constituting the film layer 18 is stored in the data server 2 so as to correspond to the position within the surface of the substrate 10 .

The control unit 20 includes a film layer data acquisition unit 25, a reflectance calculation unit 26, an output setting unit 27, and a processing control unit 28. The film layer data acquisition unit 25 obtains the film layer data of the substrate 10 from the data server 2 . The reflectance calculation unit 26 calculates the reflectance R of the measurement laser light LB2 reflected by the top surface of the substrate 10 based on the film layer data acquired by the film layer data acquisition unit 25 . The reflectance R is calculated using, for example, the survey chart shown in FIG. 10 or the like. The output setting unit 27 sets the output W of the measurement laser oscillation unit 162 when the processing irradiation point P1 moves on the planned division line 13 of the substrate 10 based on the reflectance R calculated by the reflectance calculation unit 26 . The output W is set so that the voltage V2 does not fall below the threshold V2 ₀ during substrate processing. The processing control unit 28 measures the vertical position of the processing irradiation point P1 using the setting of the output setting unit 27 while moving the processing irradiation point P1 on the planned division line 13 of the substrate 10 , and controls the light collection based on the measurement result. The vertical position of the portion 152.

FIG. 17 is a flowchart showing the processing of the control unit in the third embodiment. The process shown in FIG. 17 makes the film thickness (and thus the reflectivity) of the film layer 18 non-uniform within the surface of one substrate 10 . In addition, the process shown in FIG. 17 can also be used in a state where the film thickness of the film layer 18 is uniform throughout the surface of one substrate 10 and is non-uniform among a plurality of substrates 10 . The processing after step S501 shown in FIG. 17 starts, for example, when the transport unit 58 places the substrate 10 on the substrate holding unit 110 . In order to improve throughput, the processes of steps S501 to S503 can be executed simultaneously with the alignment process in which the alignment unit 120 detects the planned division lines 13 of the substrate 10 .

First, the film layer data acquisition unit 25 uses the imaging unit 121 and the like to acquire the identification information (such as characters, numbers, symbols, graphics, etc.) displayed on the substrate 10 held by the substrate holding unit 110, and obtains it from the external data server 2 Film layer data corresponding to the obtained identification information (step 501). Here, examples of graphics representing identification information include one-dimensional codes and two-dimensional codes.

Next, the reflectance calculation unit 26 calculates the reflectance R of the measurement laser light LB2 reflected by the top surface of the substrate 10 based on the film layer data acquired by the film layer data acquisition unit 25 (step S502). The reflectance R is calculated using the survey map shown in Fig. 10, etc. The reflectance R is stored so as to correspond to the position of the processing irradiation point P1 on the planned division line 13 .

Next, the output setting unit 27 sets the output W of the measurement laser oscillation unit 162 during substrate processing based on the reflectance R calculated by the reflectance calculation unit 26 (step S503). The output W is set so that the voltage V2 does not fall below the threshold value V2 ₀ during substrate processing, and is set so as to correspond to the position of the processing irradiation point P1 on the planned division line 13 .

Next, the processing control unit 28 performs vertical position alignment of the processing head 130 (step S504). Thereby, as shown in FIG. 6 , the frame 131 of the processing head 130 is arranged at a predetermined height from the substrate holding part 110 .

Next, the processing control unit 28 starts the movement of the processing irradiation point P1 (step S505). Specifically, the control unit 20 causes the processing irradiation point P1 to start moving from the processing start point SP shown in FIG. 7 to the processing end point EP.

Next, the processing control unit 28 controls the vertical position of the light collecting unit 152 based on the voltage ratio V1/V2 indicating the vertical position of the processing irradiation point P1 (step S506). At this time, the output W of the measurement laser oscillation unit 162 is controlled by the settings of the output setting unit 27 . Therefore, the voltage V2 can be prevented from falling below the threshold V2 ₀ during substrate processing.

Next, after the processing irradiation point P1 reaches the processing end point EP, the control unit 20 ends the movement of the processing irradiation point P1 (step S507), and ends this processing. Thereby, a plurality of processing marks extending in the X-axis direction are formed at intervals in the Y-axis direction.

Thereafter, the control unit 20 rotates the substrate holding unit 110 by 90° in the θ direction, and then forms a plurality of processing marks extending in the X-axis direction at intervals in the Y-axis direction. Thereby, processing marks can be formed along the grid-shaped planned division lines 13 set on the substrate 10 .

As described above, according to the process shown in FIG. 17 , the film layer data of the film layer 18 forming the top surface of the substrate 10 is obtained, and the measurement radar reflected by the top surface of the substrate 10 is calculated based on the obtained film layer data. The reflectance R of the radiated line LB2. Based on the calculated reflectance R, the output W of the measurement laser oscillator 162 during substrate processing is set. Since the output W during substrate processing can be set before substrate processing, the processing load of the control unit 20 during substrate processing can be reduced, thereby reducing the processing load of the control unit 20 during substrate processing.

When the film thickness of the film layer 18 (and thus the reflectance R) is not uniform within the surface of one substrate 10, the control unit 20 performs measurement while processing the one substrate 10 with the processing laser beam LB1. The output of the laser oscillator 162 is changed. This output change is performed based on the reflectance calculated by the reflectance calculation unit 26 . Either output increase or output decrease can be implemented, or both can be implemented. In addition, the number of output changes only needs to be one or more. Although the output W can be changed while one planned division line 13 is being processed, the output W can be maintained constant. When processing one planned dividing line 13 and when processing the other planned dividing line 13 , different outputs W can be set. During processing of one substrate 10, unlike the state where the output W is always fixed at the maximum output, since the output W is changed in response to the voltage V2, the power consumption of the measurement laser oscillation unit 162 can be suppressed. Furthermore, heat generation caused by the power consumption can be suppressed. Therefore, the cooling mechanism for cooling the measurement laser oscillation unit 162 can be downsized. There may even be no need for a cooling mechanism. Therefore, a small laser displacement meter can be used to measure the vertical position of the measurement irradiation point P2, and can also measure the vertical position of the processing irradiation point P1.

When the thickness of the film layer 18 (and therefore the reflectance R) is uniform within the entire surface of one substrate 10 and is non-uniform among a plurality of substrates 10 , the control unit 20 uses the processing laser light LB1 to While the plurality of substrates 10 are being processed, the output of the measurement laser oscillator 162 is changed. This output change is performed based on the reflectance measured by the reflectance calculation unit 26 . Either output increase or output decrease can be implemented, or both can be implemented. In addition, the number of output changes only needs to be one or more. Although the output W can be changed while one substrate 10 is being processed, the output W can be maintained constant. When one substrate 10 is processed and when another substrate 10 is processed, the output W can be set to be different. During the processing of a plurality of substrates 10, unlike the state where the output W is always fixed at the maximum output, since the output W is changed according to the voltage V2, the power consumption of the measurement laser oscillation unit 162 can be suppressed. Furthermore, heat generation caused by the power consumption can be suppressed. Therefore, the cooling mechanism for cooling the measurement laser oscillation unit 162 can be downsized. There may even be no need for a cooling mechanism. Therefore, a small laser displacement meter can be used to measure the vertical position of the measurement irradiation point P2, and can also measure the vertical position of the processing irradiation point P1.

The embodiments of the laser processing apparatus, the laser processing system, and the laser processing method have been described above. However, the present invention is not limited to the above-mentioned embodiments, and the spirit of the invention described in the patent claims is not limited to the above. Various changes and improvements can be made within the scope.

For example, the control unit 20 may combine two or more of the processing shown in FIG. 12 , the processing shown in FIG. 13 , the processing shown in FIG. 15 , and the processing shown in FIG. 17 to control the measurement process during substrate processing. The output W of the laser oscillation unit 162. This combination is not particularly limited.

When the film thickness of the film layer 18 (and therefore the reflectance R) is not uniform within the plane of one substrate 10 , in the above-mentioned embodiment, it is made to correspond to the position of the processing irradiation point P1 on the planned dividing line 13 The output W is set, but the output W can also be set for each scheduled division line 13 . In the latter case, since one output W is set for one planned dividing line 13, frequent switching of the output W can be avoided, thereby reducing the processing volume of the control unit 20 during substrate processing.

1: Substrate processing system (laser processing system) 2: Data server 10: Substrate 11: 1st main surface 12: 2nd main surface 13: Scheduled dividing line 14: Protective tape 15: Modified layer 17: Substrate body 18 :Coating layer 19: Notch 20: Control part 21: CPU 22: Recording medium 23: Input interface 24: Output interface 25: Coating layer data acquisition part 26: Reflectivity calculation part 27: Output setting part 28: Processing control part 30: Carrying-in part 31: Placing plate 35: Carrying-in cassette 40: Carrying-out part 41: Placing plate 45: Carrying-out cassette 50: Conveying path 51: Y-axis guide part 52: Y-axis sliding part 58: Conveying part (conveying device) 60: Alignment part (alignment device) 100: Laser processing part (laser processing device) 101: Fixing table 110: Substrate holding part 120A: Alignment part 120: Alignment part 121: Photography part 122: Reflectivity measurement Part 130: Processing head 131: Frame 135: Processing head lifting part 140: Substrate moving part (irradiation point moving part) 142: Y-axis guide part 143: Y-axis sliding part 144: X-axis guide part 145: X-axis sliding part Part 146: Rotary table 150: Laser oscillation part for processing 152: Light collecting part 153: Light collecting part box 154: Dichroic mirror 156: Direction conversion mirror 158: Light collecting part moving part 160: Height measuring part 162: For measurement Laser oscillation unit 164: Beam splitter 166: Bandpass filter 170: Reflected light receiving unit 171: Beam splitter 172: First light receiving path 173: Condensing lens 174: First light receiving element 175: Second light receiving path 176 : Second light-receiving element 177: Light-receiving range limiting part 178: Cylindrical lens 179: One-dimensional mask EP: Processing end point L: Distance LB1: Laser light for processing LB2: Laser light for measurement LB2´: Laser for inspection Radiation line P1: Irradiation point for processing P2: Irradiation point for measurement P2´: Irradiation point for inspection R, R1～R4, R1 ₀ ～R3 ₀ : Reflectivity S101～S104, S201～S204, S301～S306, S401～S406 , S501～S507: Step SP: Processing start point V2: Voltage V2 ₀ : Threshold W, W1～W3: Output X, Y, Z: Direction

[Fig. 1] is a perspective view showing a substrate before processing by the substrate processing system according to the first embodiment. [Fig. 2] It is a top view showing the substrate processing system of the first embodiment. [Fig. 3] This is a flowchart showing the substrate processing method of the first embodiment. [Fig. 4] (a) to (b) are plan views showing the laser processing portion of the first embodiment. [Fig. 5] is a front view showing the laser processing section of the first embodiment. [Fig. 6] It is a side view showing the processing head and the substrate holding part of the first embodiment. 7 is a plan view showing the moving path of the irradiation point of the processing laser light on the top surface of the substrate and an extended surface extending the top surface horizontally according to the first embodiment. [Fig. 8] is a diagram showing the path of the processing laser light and the path of the measuring laser light in the first embodiment. 9 is a diagram showing the relationship between the vertical position of the irradiation point of the measurement laser light on the top surface of the substrate and the size of the irradiation point of the measurement laser light on the top surface of the substrate in the first embodiment. [Fig. 10] This is a diagram schematically showing the relationship between the material and film thickness of the film layer forming the top surface of the substrate in the first embodiment and the reflectance of the measuring laser light on the top surface of the substrate. [Fig. 11] The relationship between the output of the measuring laser oscillation unit of the first embodiment, the reflectivity of the measuring laser light on the top surface of the substrate, and the intensity of the reflected light received by the second light-receiving element is expressed by A diagram represented schematically. [Fig. 12] This is a flowchart showing a first example of the processing of the control unit in the first embodiment. [Fig. 13] This is a flowchart showing a second example of the processing of the control unit in the first embodiment. [Fig. 14] It is a front view showing the laser processing part of the second embodiment. [Fig. 15] This is a flowchart showing the processing of the control unit in the second embodiment. [Fig. 16] This is a diagram showing the structural elements of the control unit in the third embodiment as functional blocks. [Fig. 17] This is a flowchart showing the processing of the control unit in the third embodiment.

S201~S204: steps

Claims (11)

A laser processing device includes: a substrate holding part that holds the substrate horizontally from below; a processing laser oscillation part that oscillates and emits processing laser light for processing the substrate; and an irradiation point moving part that causes the substrate holding part to The irradiation point of the processing laser light on the top surface of the held substrate moves; the height measuring part measures the vertical position of the irradiation point; and the light collecting part causes the processing laser light to move from above the irradiation point. Concentrate downward; the light collecting part moving part moves the light collecting part in the vertical direction; and the control part moves the irradiation point on a plurality of planned division lines on the top surface of the substrate while moving the irradiation point according to the direction of the irradiation point. The vertical position controls the vertical position of the light collecting part; the height measuring part includes: a measuring laser oscillation part that oscillates and emits a measuring laser light having a wavelength different from that of the processing laser light; and a reflected light receiver. The part receives the reflected light of the measurement laser light that irradiates the top surface of the substrate along the same path as the processing laser light; the control part receives the reflected light of the processing laser light after While one substrate is being processed, the output of the measurement laser oscillation unit is changed based on the intensity of the reflected light received by the reflected light receiving unit. For example, in the laser processing device of Item 1 of the patent application scope, the control part, While moving the irradiation point on the planned division line of the substrate, the intensity of the reflected light received by the reflected light receiving unit is monitored; and the output change is performed based on the monitored intensity of the reflected light. For example, the laser processing device of Item 1 or 2 of the patent application, wherein the control unit measures and irradiates the top surface of the substrate with the measurement laser light before processing the substrate with the processing laser light. At the same time, the intensity of the reflected light received by the reflected light receiving unit is determined when the irradiation point of the measurement laser light moves on the planned division line; and the output change is performed based on the measured intensity of the reflected light. For example, the laser processing device of Item 1 or 2 of the patent scope is applied for, wherein the control unit obtains information on the material and film thickness of the film layer forming the top surface of the substrate; based on the obtained information, calculates The reflectivity of the measurement laser light on the top surface of the substrate; and the output change is performed based on the calculated reflectivity of the measurement laser light. For example, the laser processing device of Item 1 or 2 of the patent application further includes an alignment part for detecting the planned division line of the substrate held by the substrate holding part; the alignment part includes a reflectance measuring part, which measures The reflectivity of the inspection laser light having the same wavelength as the measurement laser light on the top surface of the substrate; the control unit executes the reflectance based on the reflectance measured by the reflectance measurement unit of the alignment unit Output changes. A laser processing system, including: a laser processing device as described in any one of items 1 to 5 of the patent application scope; an alignment device to measure the center position of the substrate and the crystal orientation of the substrate; and a transportation device, The substrate is transported from the alignment device to the laser processing device; the alignment device includes a reflectance measurement unit that measures the intensity of the inspection laser light having the same wavelength as the measurement laser light on the top of the substrate. the reflectivity of the surface; the control unit implements the output change based on the reflectance measured by the reflectance measuring unit of the alignment device. A laser processing method, which includes measuring the vertical position of the irradiation point while moving an irradiation point of a processing laser light on a plurality of planned division lines on a top surface of a substrate that is kept horizontal, and controlling, based on the measurement results, The step of adjusting the vertical direction position of the light collecting part where the processing laser light is concentrated from above the irradiation point to the lower part; the laser processing method includes: using a measuring laser oscillation part to oscillate and emit a laser beam having the same characteristics as the processing laser The step of using measuring laser light with different wavelengths and receiving the reflected light reflected at the irradiation point of the measuring laser light with a reflected light receiving part to measure the vertical position of the irradiation point; and While the substrate is being processed with the processing laser beam, the step of changing the output of the measurement laser oscillation unit is performed based on the intensity of the reflected light received by the reflected light receiving unit. For example, the laser processing method of Item 7 of the patent application further includes: a step of monitoring the intensity of the reflected light received by the reflected light receiving part while moving the irradiation point on the planned division line of the substrate; and performing the step of changing the output according to the monitored intensity of the reflected light. For example, the laser processing method in Item 7 or 8 of the patent application further includes: before processing the substrate with the processing laser light, measuring and irradiating the measuring laser light to the top surface of the substrate while simultaneously causing The step of measuring the intensity of the reflected light received by the reflected light receiving unit when the irradiation point of the laser light moves on the planned division line; and performing the output change based on the measured intensity of the reflected light. steps. For example, the laser processing method in Item 7 or 8 of the patent scope further includes: the step of obtaining information about the material and film thickness of the film layer forming the top surface of the substrate; and calculating, based on the obtained information, the The step of determining the reflectivity of the measuring laser light on the top surface of the substrate; and the step of executing the output change based on the calculated reflectivity of the measuring laser light. For example, the laser processing method of Item 7 or 8 of the patent application further includes: the step of measuring the reflectivity of the inspection laser light with the same wavelength as the measurement laser light on the top surface of the substrate; and The step of changing the output is performed based on the measured reflectivity of the inspection laser light.