Laser processing device

Abstract

To provide a laser processing device which can independently adjust gas supplied to a laser beam emission part.SOLUTION: A laser processing device 1 includes a laser processing head 10A having an objective lens part 14 including a condenser lens 141 and a lens barrel 142, a cover 70 provided on the lens barrel 142, a first injection mechanism 201, and a second injection mechanism 202. The first injection mechanism 201 includes a first injection port 101 provided on the cover 70, a first injection part 111 for injecting gas A1 to the lens barrel 142 from the first injection port 101, and a first flow rate adjustment part 131 for adjusting a flow rate of the gas A1 in the first injection part 111. The second injection mechanism 202 includes a second injection port 106 which is provided on the cover 70, and is opened in a direction crossing an optical axis Lx of a laser beam L, a second injection part 114 for jetting gas A2 to an emission part 143 from the second injection port 106, and a second flow rate adjustment part 132 for adjusting the flow rate of the gas A2 in the second injection part 114.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a laser processing apparatus. [Background technology]

[0002] Patent Document 1 describes a laser processing device that performs laser processing along a planned dividing line of a wafer, which is a workpiece having a laminated film including a metal film formed on its surface. This device includes a laser source, and a condenser lens unit including a condenser lens that condenses the laser light emitted from the laser source onto the wafer and a condenser lens holder that houses the condenser lens. In addition, two cooling air supply ports are formed on the side of the condenser lens holder. A supply connector is connected to each of the cooling air supply ports, and an air supply device is connected to the supply connector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-109183 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned Patent Document 1 describes that when air is supplied by the air supply device, the air is supplied toward the condenser lens through two cooling air supply ports and circulates around the condenser lens in a spiral shape to cool the condenser lens. In addition, it is described that the air that has cooled the condenser lens cools the condenser lens protective plate, then passes through the laser passage hole of the laser nozzle and is led to the processing point. In this way, in the laser processing device described in Patent Document 1, the air for cooling the condenser lens is passed through the laser passage hole of the laser nozzle and led to the processing point.

[0005] In recent years, in laser processing, the output of laser light has been increased in response to various processing requirements, such as multi-focus processing for tact time improvement. Therefore, there is a demand for cooling the condenser lens in order to suppress the problem of heat generation in the condenser lens due to the high-output laser light. To achieve this, it is conceivable to supply cooling air to the condenser lens, as in the laser processing device described in the above Patent Document 1.

[0006] On the other hand, there is a demand for suppressing adhesion of debris generated on the wafer by irradiating the wafer with the laser light to the laser light output part of the focusing lens. For this reason, it is desirable to supply a gas such as protective air to the laser light output part. However, if the gas supplied to the output part hits, for example, a power meter and cools the power meter, there is a risk of an error in measuring the power of the laser light by the power meter. Therefore, it is desirable to configure the gas supplied to the output part so that the flow rate can be adjusted at any timing.

[0007] However, in the laser processing device described in the above Patent Document 1, although air is supplied to the exit part (laser passage hole) of the laser nozzle, the air is also used to cool the condenser lens. Therefore, when the air flow rate is adjusted to stop the supply of air to the exit part at a predetermined timing, the cooling of the condenser lens is also stopped. If the laser light is emitted in a state where the cooling of the condenser lens is stopped, the heat generated by the condenser lens will have an adverse effect on the processing result.

[0008] Therefore, in the laser processing apparatus as described above, it is desirable to configure the gas supplied to the laser light emission part so that it is possible to independently adjust the gas.

[0009] In view of the above, an object of the present disclosure is to provide a laser processing apparatus capable of independently adjusting the gas supplied to the laser light emission part. [Means for solving the problem]

[0010] The laser processing device according to the present disclosure is, [1] "a laser processing device that irradiates a target object with a laser beam to process the target object, comprising: a laser processing head having a condensing lens unit including a condensing lens for condensing the laser beam toward the target object and a lens barrel that holds the condensing lens therein; a cover provided on the lens barrel to cover the lens barrel while forming a space between the lens barrel and the cover; a first injection mechanism for injecting gas into the lens barrel; and a second injection mechanism for injecting gas into at least an emission portion of the laser beam in the condensing lens unit, the second injection mechanism includes a second injection port provided in the cover and opening in a direction intersecting the optical axis of the laser light in the focusing lens unit, a second injection port that injects gas from the second injection port into the emission section, and a second flow rate adjustment unit for adjusting the flow rate of gas in the second injection port.

[0011] In the laser processing device according to the above [1], the laser processing head has a condensing lens unit including a condensing lens and a lens barrel that holds the condensing lens. A gas is injected into the lens barrel by a first injection mechanism, and a gas is injected into the laser light emission part of the condensing lens unit by a second injection mechanism. More specifically, the first injection mechanism includes a first injection port that communicates with a space between a cover provided on the lens barrel and the lens barrel, and a first injection part that injects gas into the lens barrel by introducing gas from the first injection port into the space. The second injection mechanism includes a second injection port and a second injection part that injects gas from the second injection port into the laser light emission part. This allows the lens barrel and the condensing lens in the lens barrel to be cooled, and the laser light emission part to be protected from debris adhesion. In particular, the first injection mechanism includes a first flow rate adjustment part for adjusting the flow rate of gas of the first injection part, and the second injection mechanism includes a second flow rate adjustment part for adjusting the flow rate of gas of the second injection part. Therefore, the supply of gas to the laser light emission part by the second injection part can be adjusted independently of the supply of gas by the first injection part. The second injection port is opened in a direction intersecting the optical axis of the laser light in the focusing lens unit. Therefore, when the second injection part is injecting gas, the gas injected from the second injection port flows directly in the optical axis direction and is prevented from hitting an object or a power meter arranged opposite the focusing lens unit.

[0012] The laser processing apparatus according to the present disclosure may be the laser processing apparatus according to the above [1], in which the second injection mechanism includes a third injection port provided in the cover so as to communicate with the space, and the second injection unit introduces gas from the third injection port into the space to inject the gas into the lens barrel, and also discharges gas from the space through the second injection port to inject the gas into the emission unit. In the laser processing apparatus according to [2], the gas introduced into the space between the cover and the lens barrel from the third injection port communicating with the space and injected into the lens barrel is discharged from the space through the second injection port and injected into the emission unit. Therefore, the gas supplied to the emission unit of the laser light is given a cooling function for the lens barrel and the condenser lens in the lens barrel, making it possible to perform more effective cooling.

[0013] The laser processing device according to the present disclosure may be [3] "the laser processing device according to the above [1], in which the second injection port is provided in the cover separated from the space, and the second injection part injects gas from the second injection port to the emission part without passing through the space." According to the laser processing device according to [3], it is possible to clearly distinguish between cooling of the lens barrel and the focusing lens by injection of gas from the first injection mechanism and protection of the emission part of the laser light by injection of gas from the second injection mechanism.

[0014] The laser processing device according to the present disclosure may be [4] "the laser processing device according to any one of the above [1] to [3], in which the first injection section and the second injection section inject gas from the same supply source." According to the laser processing device according to [4], it is possible to realize cooling of the lens barrel and the focusing lens and protection of the laser light emission section with a simpler configuration.

[0015] The laser processing device according to the present disclosure may be [5] "the laser processing device according to any one of the above [1] to [4], wherein the emission section includes a protective cover that covers the emission surface of the condenser lens of the laser light." According to the laser processing device according to [5], the emission surface of the condenser lens of the laser light is reliably protected.

[0016] The laser processing apparatus according to the present disclosure may be [6] "the laser processing apparatus according to any one of the above [1] to [5], which includes a control unit, and the control unit performs a power measurement process of emitting a laser beam from the emission unit and measuring the power of the laser beam using a power meter arranged opposite the emission unit, and a flow rate reduction process of controlling the second flow rate adjustment unit to reduce the flow rate of the gas in the second injection unit before or during the power measurement process." According to the laser processing apparatus according to [6], when measuring the power of the laser beam using a power meter arranged opposite the emission unit of the laser beam, the flow rate of the gas injected into the emission unit is reduced. This suppresses the occurrence of measurement errors caused by the gas hitting the power meter and cooling the power meter.

[0017] The laser processing device according to the present disclosure may be the laser processing device described in [6] above, in which the control unit performs a processing process for processing the object arranged opposite the emission unit by emitting the laser light from the emission unit after the flow rate reduction process, and a flow rate increase process for increasing the flow rate of gas in the second injection unit by controlling the second flow rate adjustment unit after the flow rate reduction process and before or during the processing process. According to the laser processing device according to [7], the flow rate of gas injected into the emission unit is increased during laser processing of a wafer arranged opposite the emission unit of laser light. This ensures that the emission unit is protected during laser processing.

[0018] The laser processing device according to the present disclosure may be the laser processing device according to [8] above, "wherein the control unit controls the first flow rate adjustment unit to perform a cooling process for cooling the lens barrel by injecting gas from the first injection unit before or during each of the power measurement process and the processing process." According to the laser processing device according to [8], the lens barrel and the focusing lens in the lens barrel are cooled both during power measurement by a power meter and during laser processing of an object.

[0019] The laser processing device according to the present disclosure may be the laser processing device according to [9] or [8] above, in which "the object has a plurality of lines extending along one direction, and the control unit performs, as the processing, a scanning process of scanning the object with the laser light while moving a focal point of the laser light along one of the lines along the X direction in a state in which the object is arranged so that the plurality of lines extend along the X direction and are arranged in a Y direction intersecting the X direction, and the second injection port is opened in a direction intersecting the X direction." According to the laser processing device according to [9], it is possible to blow away debris generated during laser processing of the object in a direction intersecting the processing progress direction (X direction) by gas injected into an emission part of the laser light through the second injection port.

[0020] The laser processing apparatus according to the present disclosure may be

[10] "the laser processing apparatus described in [9] above, in which the control unit performs the scanning process multiple times from the line on one side of the Y direction to the line on the other side, and the second jet nozzle opens in a direction from the other side to the one side of the Y direction." According to the laser processing apparatus according to

[10] , debris generated during laser processing of the object is blown from an unprocessed area of ​​the object to a processed area by gas injected into an emission part of the laser light through the second jet nozzle, thereby preventing debris from scattering in the unprocessed area of ​​the object. Effect of the Invention

[0021] According to the present disclosure, it is possible to provide a laser processing device capable of independently adjusting the gas supplied to the laser light emission part. [Brief description of the drawings]

[0022] [Figure 1] 1 is a perspective view of a laser processing apparatus according to an embodiment; [Diagram 2] 2 is a front view of a portion of the laser processing apparatus shown in FIG. 1. [Diagram 3] 2 is a front view of the laser processing head shown in FIG. 1. [Figure 4] FIG. 2 is a side view of the laser processing head shown in FIG. [Diagram 5] FIG. 5 is a configuration diagram of the laser processing head shown in FIG. 4. [Figure 6] 2 is a schematic diagram showing a first jet mechanism and a second jet mechanism of the laser processing apparatus shown in FIG. 1. [Figure 7] FIG. 7 is a diagram showing a display example of the display shown in FIG. 6. [Figure 8] 4 is a flowchart showing a step of a laser processing method according to one embodiment. [Figure 9] FIG. 9 is a schematic diagram for explaining one step of the flowchart shown in FIG. 8. [Figure 10] FIG. 9 is a schematic diagram for explaining one step of the flowchart shown in FIG. 8. [Figure 11] FIG. [Figure 12] FIG. 9 is a schematic diagram for explaining one step of the flowchart shown in FIG. 8. [Figure 13] 13 is a schematic diagram showing a first jet mechanism and a second jet mechanism of a laser processing apparatus according to a modified example. FIG. [Figure 14] 13 is a schematic diagram showing a first jet mechanism and a second jet mechanism of a laser processing apparatus according to another modified example. FIG. [Figure 15] FIG. 11 is a schematic diagram showing a first jet mechanism and a second jet mechanism of a laser processing apparatus according to still another modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment according to the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted. [Laser processing equipment configuration]

[0024] 1, the laser processing device 1 includes a plurality of moving mechanisms 5, 6, a support unit 7, a pair of laser processing heads 10A, 10B, a light source unit 8, and a control unit 9. Hereinafter, an orthogonal coordinate system consisting of an X-axis, a Y-axis, and a Z-axis may be illustrated. As an example, the Z-direction is the vertical direction, and the X-direction and the Y-direction are the horizontal directions.

[0025] The movement mechanism 5 has a fixed part 51, a moving part 53, and an attachment part 55. The fixed part 51 is attached to the device frame 1a. The moving part 53 is attached to a rail provided on the fixed part 51, and can move along the Y direction. The attachment part 55 is attached to a rail provided on the moving part 53, and can move along the X direction.

[0026] The movement mechanism 6 has a fixed part 61, a pair of moving parts 63, 64, and a pair of mounting parts 65, 66. The fixed part 61 is attached to the device frame 1a. Each of the pair of moving parts 63, 64 is attached to a rail provided on the fixed part 61, and each can move independently along the Y direction. The mounting part 65 is attached to a rail provided on the moving part 63, and can move along the Z direction. The mounting part 66 is attached to a rail provided on the moving part 64, and can move along the Z direction.

[0027] The support unit 7 is attached to a rotation shaft provided on the mounting unit 55 of the moving mechanism 5, and can rotate about an axis parallel to the Z direction. The support unit 7 supports an object W. The object W is, for example, a wafer.

[0028] 1 and 2, the laser processing head 10A is attached to an attachment portion 65 of the moving mechanism 6. The laser processing head 10A irradiates laser light (processing light) L onto the object W supported by the support portion 7 while facing the support portion 7 in the Z direction. The laser processing head 10B is attached to an attachment portion 66 of the moving mechanism 6. The laser processing head 10B irradiates laser light L onto the object W supported by the support portion 7 while facing the support portion 7 in the Z direction.

[0029] As shown in Fig. 1, the light source unit 8 has a pair of light sources (first light sources) 81, 82. The pair of light sources 81, 82 are attached to the device frame 1a. Each of the pair of light sources 81, 82 emits laser light L. The laser light L emitted from the emission portion 81a of the light source 81 is guided to the laser processing head 10A by an optical fiber 2. The laser light L emitted from the emission portion 82a of the light source 82 is guided to the laser processing head 10B by another optical fiber 2.

[0030] The control unit 9 controls each part of the laser processing apparatus 1 (the multiple moving mechanisms 5, 6, the pair of laser processing heads 10A, 10B, the light source unit 8, the first ejection mechanism 201, and the second ejection mechanism 202, etc.). The control unit 9 is configured as a computer device including a processor, a memory, a storage, a communication device, etc. In the control unit 9, software (programs) loaded into the memory, etc. are executed by the processor, and the reading and writing of data in the memory and storage, as well as communication by the communication device, are controlled by the processor. In this way, the control unit 9 realizes various functions. The control unit 9 has a display 91. The display 91 displays various information. The display 91 may be configured as a touch panel that accepts input of instructions by an operator.

[0031] The laser processing apparatus 1 configured as above can be used for various purposes, such as a dicing process for dividing a wafer, a slicing process for thinning a wafer, and a trimming process for removing the outer periphery from a wafer. Here, an example of processing by the laser processing apparatus 1 will be described. The example of processing is an example of forming modified regions Mr inside an object W, which is a wafer, along each of a plurality of lines WL set in a lattice pattern in order to cut the object W into a plurality of chips (i.e., an example of the first half of a dicing process) (see FIG. 12).

[0032] First, the movement mechanism 5 moves the support part 7 along each of the X direction and the Y direction so that the support part 7 supporting the object W faces the pair of laser processing heads 10A, 10B in the Z direction. Next, the movement mechanism 5 rotates the support part 7 about an axis parallel to the Z direction as a center line so that a plurality of lines WL extending in one direction on the object W are aligned along the X direction.

[0033] Next, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the focal point of the laser light L emitted from the laser processing head 10A (hereinafter referred to as "laser light L of the laser processing head 10A") is located on one line WL extending in one direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction so that the focal point of the laser light L emitted from the laser processing head 10B (hereinafter referred to as "laser light L of the laser processing head 10B") is located on another line WL extending in one direction. Next, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the focal point of the laser light L of the laser processing head 10A is located inside the target object W. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the focal point of the laser light L of the laser processing head 10B is located inside the target object W.

[0034] Next, the light source 81 emits the laser light L and the laser processing head 10A irradiates the laser light L on the object W, and the light source 82 emits the laser light L and the laser processing head 10B irradiates the laser light L on the object W. At the same time, the moving mechanism 5 moves the support part 7 along the X direction so that the focal point of the laser light L of the laser processing head 10A moves relatively along one line WL extending in one direction and the focal point of the laser light L of the laser processing head 10B moves relatively along another line WL extending in one direction. In this way, the laser processing device 1 forms a modified region Mr inside the object W along each of a plurality of lines WL extending in one direction on the object W.

[0035] Next, the movement mechanism 5 rotates the support 7 about an axis parallel to the Z direction as a center line so that a plurality of lines extending in another direction perpendicular to the one direction on the target object W are aligned along the X direction.

[0036] Next, the moving mechanism 6 moves the laser processing head 10A along the Y direction so that the focal point of the laser light L of the laser processing head 10A is located on one line extending in the other direction. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Y direction so that the focal point of the laser light L of the laser processing head 10B is located on another line extending in the other direction. Next, the moving mechanism 6 moves the laser processing head 10A along the Z direction so that the focal point of the laser light L of the laser processing head 10A is located inside the object W. On the other hand, the moving mechanism 6 moves the laser processing head 10B along the Z direction so that the focal point of the laser light L of the laser processing head 10B is located inside the object W.

[0037] Next, the light source 81 emits the laser light L and the laser processing head 10A irradiates the laser light L on the object W, and the light source 82 emits the laser light L and the laser processing head 10B irradiates the laser light L on the object W. At the same time, the moving mechanism 5 moves the support part 7 along the X direction so that the focal point of the laser light L of the laser processing head 10A moves relatively along one line extending in the other direction and the focal point of the laser light L of the laser processing head 10B moves relatively along another line extending in the other direction. In this way, the laser processing device 1 forms a modified region inside the object W along each of a plurality of lines extending in the other direction perpendicular to the one direction in the object W.

[0038] In one example of the above processing, each of the pair of light sources 81, 82 emits laser light L that is transparent to the object W, for example, by a pulse oscillation method. When such laser light L is focused inside the object W, the laser light L is particularly absorbed in a portion corresponding to the focusing point of the laser light L, and a modified region Mr is formed inside the object W. The modified region Mr is a region that differs in density, refractive index, mechanical strength, and other physical properties from the surrounding non-modified regions. Examples of modified regions include a melting process region, a crack region, an insulation breakdown region, and a refractive index change region.

[0039] When the laser light L emitted by the pulse oscillation method is irradiated onto the object W and the focal point of the laser light L is moved relatively along a line set on the object W, multiple modified spots are formed lined up in a row along the line. One modified spot is formed by irradiating one pulse of the laser light L. A row of modified regions Mr is a collection of multiple modified spots lined up in a row. Adjacent modified spots may be connected to each other or separated from each other depending on the relative moving speed of the focal point of the laser light L with respect to the object W and the repetition frequency of the laser light L. [Laser processing head configuration]

[0040] As shown in FIGS. 2, 3, and 4, the laser processing head 10A includes a housing 11, an entrance section 12, a laser light adjustment section 13, and an objective lens section 14 (a focusing lens unit).

[0041] The housing 11 has a first wall portion 21 and a second wall portion 22, a third wall portion 23 and a fourth wall portion 24, and a fifth wall portion 25 and a sixth wall portion 26. The first wall portion 21 and the second wall portion 22 face each other in the X direction. The third wall portion 23 and the fourth wall portion 24 face each other in the Y direction. The fifth wall portion 25 and the sixth wall portion 26 face each other in the Z direction.

[0042] The distance between the third wall portion 23 and the fourth wall portion 24 is smaller than the distance between the first wall portion 21 and the second wall portion 22. The distance between the first wall portion 21 and the second wall portion 22 is smaller than the distance between the fifth wall portion 25 and the sixth wall portion 26. The distance between the first wall portion 21 and the second wall portion 22 may be equal to the distance between the fifth wall portion 25 and the sixth wall portion 26, or may be larger than the distance between the fifth wall portion 25 and the sixth wall portion 26.

[0043] In the laser processing head 10A, the first wall 21 is located on the opposite side to the fixed portion 61 of the moving mechanism 6, and the second wall 22 is located on the fixed portion 61 side. The third wall 23 is located on the mounting portion 65 side of the moving mechanism 6, and the fourth wall 24 is located on the opposite side to the mounting portion 65 and on the laser processing head 10B side. The fifth wall 25 is located on the opposite side to the support portion 7, and the sixth wall 26 is located on the support portion 7 side.

[0044] The housing 11 is configured so that the housing 11 is attached to the attachment portion 65 in a state where the third wall portion 23 is disposed on the attachment portion 65 side of the moving mechanism 6. Specifically, it is as follows. The attachment portion 65 has a base plate 65a and an attachment plate 65b. The base plate 65a is attached to a rail provided on the moving portion 63. The attachment plate 65b is erected on the end portion of the base plate 65a on the laser processing head 10B side. The housing 11 is attached to the attachment portion 65 by screwing the bolt 28 into the attachment plate 65b via the pedestal 27 in a state where the third wall portion 23 is in contact with the attachment plate 65b. The pedestal 27 is provided on each of the first wall portion 21 and the second wall portion 22. The housing 11 is detachable from the attachment portion 65.

[0045] The incident portion 12 is disposed on the fifth wall portion 25. The incident portion 12 causes the laser light L to be incident into the housing 11. The incident portion 12 is biased toward the first wall portion 21 in the X direction and toward the fourth wall portion 24 in the Y direction. That is, the distance between the incident portion 12 and the first wall portion 21 in the X direction is smaller than the distance between the incident portion 12 and the second wall portion 22 in the X direction, and the distance between the incident portion 12 and the fourth wall portion 24 in the Y direction is smaller than the distance between the incident portion 12 and the third wall portion 23 in the X direction.

[0046] The incident part 12 is connected to the output end 2a of the optical fiber 2. Specifically, the incident part 12 is a part including a hole 25a formed in the fifth wall part 25. The fifth wall part 25 is provided with an attachment part 25b. The main body part 2b of the output end 2a is attached to the attachment part 25b with a bolt or the like. In this state, the tip part 2c of the output end 2a passes through the hole 25a. This makes the output end 2a of the optical fiber 2 detachable from the incident part 12. A cover 25c is disposed between the fifth wall part 25 and the main body part 2b. The cover 25c covers the gap formed between the hole 25a and the tip part 2c. As an example, in the output end 2a, an isolator that suppresses return light is disposed in the main body part 2b, and a collimator lens that collimates the laser light L is disposed in the tip part 2c. The incident part 12 may be a connector or the like configured to be connected to the output end 2a of the optical fiber 2.

[0047] The laser beam adjustment unit 13 is disposed in the housing 11. The laser beam adjustment unit 13 adjusts the laser beam L incident from the incident portion 12. The laser beam adjustment unit 13 is disposed in the housing 11 on the fourth wall portion 24 side with respect to the partition wall portion 29. The laser beam adjustment unit 13 is attached to the partition wall portion 29. The partition wall portion 29 is provided in the housing 11 and divides the area in the housing 11 into an area on the third wall portion 23 side and an area on the fourth wall portion 24 side. The partition wall portion 29 is configured as a part of the housing 11. Each component of the laser beam adjustment unit 13 is attached to the partition wall portion 29 on the fourth wall portion 24 side. The partition wall portion 29 functions as an optical base that supports each component of the laser beam adjustment unit 13.

[0048] The objective lens section 14 is disposed on the sixth wall section 26. Specifically, the objective lens section 14 is disposed on the sixth wall section 26 in a state where it passes through a hole 26a (see FIG. 5) formed in the sixth wall section 26. The objective lens section 14 emits the laser light L adjusted by the laser light adjustment section 13 to the outside of the housing 11 while concentrating the laser light L. The objective lens section 14 is biased toward the second wall section 22 in the X direction and toward the fourth wall section 24 in the Y direction. That is, the distance between the objective lens section 14 and the second wall section 22 in the X direction is smaller than the distance between the objective lens section 14 and the first wall section 21 in the X direction, and the distance between the objective lens section 14 and the fourth wall section 24 in the Y direction is smaller than the distance between the objective lens section 14 and the third wall section 23 in the X direction.

[0049] As shown in FIG. 5, the laser beam adjusting unit 13 has a reflecting unit 31, an attenuator 32, and a reflecting unit 33. The reflecting unit 31, the attenuator 32, and the reflecting unit 33 are arranged on a first straight line SL1 extending along the X direction. The reflecting unit 31 faces the incident unit 12 in the Z direction. That is, the reflecting unit 31 faces the output end 2a of the optical fiber 2 in the Z direction. The reflecting unit 31 reflects the laser beam L incident from the incident unit 12 to the second wall unit 22 side. The attenuator 32 adjusts the output of the laser beam L reflected by the reflecting unit 31. The reflecting unit 33 reflects the laser beam L, the output of which has been adjusted by the attenuator 32, to the sixth wall unit 26 side. Each of the reflecting units 31 and 33 is, for example, a mirror or a prism.

[0050] The laser light adjusting unit 13 further includes a beam expander 34 and a reflecting unit 35. The reflecting unit 33, the beam expander 34, and the reflecting unit 35 are arranged on a second straight line SL2 extending along the Z direction. The beam expander 34 expands the diameter of the laser light L reflected by the reflecting unit 33. The reflecting unit 35 reflects the laser light L, the diameter of which has been expanded by the beam expander 34, toward the first wall unit 21 side and the fifth wall unit 25 side. The reflecting unit 35 is, for example, a mirror or a prism.

[0051] The laser light adjustment unit 13 further includes a spatial light modulator 36 and an imaging optical system 37. The spatial light modulator 36, the imaging optical system 37, and the objective lens unit 14 are arranged on a third straight line SL3 extending along the Z direction. The spatial light modulator 36 reflects the laser light L reflected by the reflecting unit 35 toward the sixth wall unit 26 while modulating the laser light L. The spatial light modulator 36 is a reflective spatial light modulator. The spatial light modulator 36 is, for example, an LCOS (Liquid Crystal on Silicon)-SLM (Spatial Light Modulator). The imaging optical system 37 constitutes a double-telecentric optical system in which the reflecting surface 36a of the spatial light modulator 36 and the entrance pupil surface 14a of the objective lens unit 14 are in an imaging relationship. The imaging optical system 37 is constituted by a plurality of lenses.

[0052] The first straight line SL1, the second straight line SL2, and the third straight line SL3 are located on the same plane perpendicular to the Y direction. The second straight line SL2 is located on the second wall portion 22 side with respect to the third straight line SL3. In the laser processing head 10A, the laser light L incident from the incident portion 12 into the housing 11 along the Z direction is reflected by the reflecting portion 31 and travels on the first straight line SL1. The laser light L traveling on the first straight line SL1 is reflected by the reflecting portion 33 and travels on the second straight line SL2. The laser light L traveling on the second straight line SL2 is reflected by the reflecting portion 35 and the spatial light modulator 36 in sequence and travels on the third straight line SL3. The laser light L traveling on the third straight line SL3 is emitted from the objective lens portion 14 to the outside of the housing 11 along the Z direction.

[0053] The laser processing head 10A further includes a dichroic mirror 15, an observation unit 16, a distance measuring unit 100, a drive unit 18, and a circuit unit 19.

[0054] The dichroic mirror 15 is disposed on the third straight line SL3 between the imaging optical system 37 and the objective lens unit 14. That is, the dichroic mirror 15 is disposed in the housing 11 between the laser light adjustment unit 13 and the objective lens unit 14. The dichroic mirror 15 is attached to the partition wall unit 29 on the fourth wall unit 24 side. The dichroic mirror 15 transmits the laser light L. From the viewpoint of suppressing astigmatism, the dichroic mirror 15 is preferably, for example, a cube type or a type of two plates arranged to have a twisted relationship.

[0055] The observation unit 16 is disposed on the first wall 21 side with respect to the third straight line SL3 within the housing 11. That is, the observation unit 16 is disposed on the first wall 21 side with respect to the objective lens unit 14 in the X direction. The observation unit 16 is attached to the partition wall unit 29 on the fourth wall 24 side. The observation unit 16 irradiates the surface of the object W with observation light L10 (e.g., visible light) for observing the surface of the object W (e.g., the surface on the side where the laser light L is incident), and detects the observation light L10 reflected by the surface of the object W.

[0056] In this embodiment, the observation light L10 emitted from the observation unit 16 is reflected successively by the beam splitter 20 and the dichroic mirror 15, passes through the objective lens unit 14, is emitted to the outside of the housing 11, and is irradiated onto the surface of the object W. The observation light L10 reflected by the surface of the object W passes through the objective lens unit 14, enters the housing 11, is reflected successively by the dichroic mirror 15 and the beam splitter 20, and enters the observation unit 16. The beam splitter 20 is attached to the partition wall unit 29 on the fourth wall unit 24 side.

[0057] The distance measuring unit 100 is disposed on the first wall 21 side with respect to the third straight line SL3 within the housing 11. That is, the distance measuring unit 100 is disposed on the first wall 21 side with respect to the objective lens unit 14 in the X direction. The distance measuring unit 100 is attached to the partition wall unit 29 on the fourth wall 24 side. The distance measuring unit 100 irradiates the surface of the object W with distance measuring light L20 (e.g., laser light) for measuring the distance between the surface of the object W (e.g., the surface on the side where the laser light L is incident) and the objective lens unit 14, and detects the distance measuring light L20 reflected by the surface of the object W.

[0058] In this embodiment, the distance measurement light L20 emitted from the distance measurement unit 100 passes through the beam splitter 20, is reflected by the dichroic mirror 15, passes through the objective lens unit 14, is emitted outside the housing 11, and is irradiated onto the surface of the object W. The distance measurement light L20 reflected by the surface of the object W passes through the objective lens unit 14 and enters the housing 11, is reflected by the dichroic mirror 15, passes through the beam splitter 20, and enters the distance measurement unit 100. Note that the wavelengths of the laser light L, the distance measurement light L20, and the observation light L10 are different from each other (at least their central wavelengths are shifted from each other).

[0059] The driving unit 18 is attached to the objective lens unit 14 on the entrance pupil plane 14a side of the objective lens unit 14. As an example, the objective lens unit 14 is attached to the housing 11 via the driving unit 18. The driving unit 18 moves the objective lens unit 14 in the Z direction by, for example, the driving force of a piezoelectric element.

[0060] As shown in FIG. 3 and FIG. 5, the circuit unit 19 is disposed on the third wall 23 side with respect to the partition wall 29 in the housing 11. That is, the circuit unit 19 is disposed on the third wall 23 side with respect to the laser light adjustment unit 13, the distance measurement unit 100, and the observation unit 16 in the housing 11. The circuit unit 19 is spaced apart from the partition wall 29. The circuit unit 19 is, for example, a plurality of circuit boards. The circuit unit 19 processes the signal output from the distance measurement unit 100 and the signal input to the spatial light modulator 36. The circuit unit 19 controls the driving unit 18 based on the signal output from the distance measurement unit 100. As an example, the circuit unit 19 controls the driving unit 18 based on the signal output from the distance measurement unit 100 so that the distance between the surface of the object W and the objective lens unit 14 is kept constant (i.e., the distance between the surface of the object W and the focal point of the laser light L is kept constant).

[0061] The partition wall 29 is formed with notches, holes, and the like (not shown) through which wires pass for electrically connecting the observation unit 16, the distance measurement unit 100, the drive unit 18, and the spatial light modulator 36 to the circuit unit 19. The housing 11 is also provided with a connector (not shown) to which wires, and the like, for electrically connecting the circuit unit 19 to the control unit 9 are connected.

[0062] The laser processing head 10B, like the laser processing head 10A, includes a housing 11, an incident section 12, a laser light adjustment section 13, an objective lens section 14, a dichroic mirror 15, an observation section 16, a distance measurement section 100, a drive section 18, and a circuit section 19. However, as shown in Fig. 2, each component of the laser processing head 10B is arranged so as to have a plane-symmetric relationship with each component of the laser processing head 10A with respect to a virtual plane that passes through the midpoint between a pair of mounting sections 65, 66 and is perpendicular to the Y direction.

[0063] For example, the housing 11 of the laser processing head 10A is attached to the mounting portion 65 so that the fourth wall portion 24 is located on the laser processing head 10B side relative to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25. In contrast, the housing 11 of the laser processing head 10B is attached to the mounting portion 66 so that the fourth wall portion 24 is located on the laser processing head 10A side relative to the third wall portion 23 and the sixth wall portion 26 is located on the support portion 7 side relative to the fifth wall portion 25.

[0064] The housing 11 of the laser processing head 10B is configured so that the housing 11 is attached to the mounting portion 66 with the third wall portion 23 disposed on the mounting portion 66 side. Specifically, it is as follows. The mounting portion 66 has a base plate 66a and a mounting plate 66b. The base plate 66a is attached to a rail provided on the moving portion 63. The mounting plate 66b is erected at the end of the base plate 66a on the laser processing head 10A side. The housing 11 of the laser processing head 10B is attached to the mounting portion 66 with the third wall portion 23 in contact with the mounting plate 66b. The housing 11 of the laser processing head 10B is detachable from the mounting portion 66. [Configuration of injection mechanism]

[0065] 6, the laser processing device 1 includes a configuration for injecting gas toward the objective lens unit 14. More specifically, the laser processing device 1 includes a cover 70, a first injection mechanism 201, and a second injection mechanism 202. The objective lens unit 14 includes at least one (a plurality of in the illustrated example) condenser lens 141 for condensing the laser light L toward the target W, and a lens barrel 142 that holds the condenser lens 141 therein.

[0066] The cover 70 is formed in a cylindrical shape with both ends open so as to cover the lens barrel 142 while forming a space 71 between the cover 70 and the lens barrel 142, and is provided on the lens barrel 142. The cover 70 exposes the entrance pupil surface 14a and the light exit surface (exit surface) 14b of the objective lens unit 14. The light exit surface 14b is included in the exit portion 143 of the laser light L in the objective lens unit 14. A convex portion 144 is formed on the outer peripheral surface of the lens barrel 142 extending in a direction along the optical axis Lx of the laser light L (here, the Z direction), and the width of the space 71 between the cover 70 and the lens barrel 142 is maintained by the convex portion 144. In this embodiment, the objective lens unit 14 is not fixed to the cover 70, and is movable in the Z direction within the cover 70. Therefore, the objective lens unit 14 can be driven by the drive unit 18 within the cover 70 independently of the cover 70. As an example, the cover 70 is fixed to the housing 11 .

[0067] The first injection mechanism 201 is for cooling the lens barrel 142 and the condenser lens 141 in the lens barrel 142 by injecting gas A1 (air as an example) into the lens barrel 142. The first injection mechanism 201 has a plurality of (three in this case) first injection ports 101, 102, and 103, a plurality of (three in this case) first injection units 111, 112, and 113, and a first flow rate adjustment unit 131. The first injection ports 101, 102, and 103 are provided in the cover 70 so as to penetrate the cover 70 and communicate with the space 71 inside the cover 70. The first injection port 101, the first injection port 102, and the first injection port 103 are arranged in order in a direction from the entrance pupil surface 14a side of the lens barrel 142 toward the emission unit 143 (here, the negative Z-axis direction).

[0068] As an example, the first ejection port 101 is provided on the entrance pupil plane 14a side from the center of the lens barrel 142 in the Z direction, the first ejection port 102 is provided near the center of the lens barrel 142 in the Z direction, and the first ejection port 103 is provided on the emission section 143 side from the center of the lens barrel 142 in the Z direction. All of the first ejection ports 101, 102, and 103 are open in a direction (here, the Y direction) intersecting the Z direction (i.e., the optical axis Lx of the laser light L).

[0069] The first ejection parts 111, 112, and 113 are nozzles that eject the gas A1. The first ejection part 111 is fitted into the first ejection port 101, the first ejection part 112 is fitted into the first ejection port 102, and the first ejection part 113 is fitted into the first ejection port 103. The tips of the first ejection parts 111, 112, and 113 are exposed in the space 71. As a result, the first ejection parts 111, 112, and 113 introduce the gas A1 into the space 71 from the first ejection ports 101, 102, and 103, respectively, to eject the gas A1 into the lens barrel 142. The first ejection parts 111, 112, and 113 eject the gas A1 in the same direction (here, the Y direction) as the opening direction of the first ejection ports 101, 102, and 103, respectively.

[0070] In this embodiment, the first injection parts 111, 112, and 113 are connected to a common first flow rate adjustment part 131 (however, they may be connected to separate first flow rate adjustment parts 131), and inject the gas A1 sent via the first flow rate adjustment part 131. The first flow rate adjustment part 131 is connected between the gas supply source GA, and adjusts the flow rate of the gas A1 in response to a signal from the control part 9, thereby adjusting the flow rate of the gas A1 in the first injection parts 111, 112, and 113.

[0071] In addition, the cover 70 is provided with one outlet 105, for example, in a portion (here, a position facing the first outlet 103) facing the portion of the cover 70 where the first outlets 101, 102, 103 are provided. A part of the gas A1 introduced into the space 71 from the first outlets 101, 102, 103 by the first injection parts 111, 112, 113 flows along the outer circumferential surface of the lens barrel 142 and is discharged from the outlet 105 to the outside of the space 71. In addition, a gap is formed between the end of the cover 70 on the entrance pupil surface 14a side and the end of the objective lens part 14 on the entrance pupil surface 14a side, and another part of the gas A1 introduced into the space 71 from the first outlets 101, 102, 103 by the first injection parts 111, 112, 113 flows along the outer circumferential surface of the lens barrel 142 and is discharged from the gap to the outside of the space 71.

[0072] The second jet mechanism 202 injects gas A2 (e.g., air) at least to the emission part 143 of the laser light L in the objective lens part 14 to protect the emission part 143 from debris generated at the object W during laser processing of the object W. The second jet mechanism 202 has a third jet port 104, a second jet port 106, a second jet part 114, and a second flow rate adjustment part 132. The third jet port 104 is provided in the cover 70 so as to penetrate the cover 70 and communicate with the space 71 inside the cover 70. The third jet port 104 is provided closer to the emission part 143 side than the first jet port 103, and is arranged in order in the Z direction together with the first jet ports 101, 102, and 103. The third jet port 104 opens in a direction intersecting the Z direction (here, the Y direction). In this embodiment, the third injection port 104 opens in the same direction as the first injection portions 111, 112, and 113.

[0073] The second ejection port 106 is provided in the cover 70 as a gap between an end of the cover 70 on the side of the emission section 143 and an end of the objective lens section 14 on the side of the emission section 143. More specifically, an opening is formed in the end of the cover 70 on the side of the emission section 143 to expose the light exit surface 14b when viewed from the Z direction, and the second ejection port 106 is formed as a gap between the edge of the opening and the objective lens section 14. The second ejection port 106 opens in a direction intersecting the Z direction (here, the negative Y-axis direction).

[0074] The second ejection part 114 is a nozzle that ejects the gas A2. The second ejection part 114 is fitted into the third ejection port 104. The tip of the second ejection part 114 is exposed in the space 71. Thus, the second ejection part 114 ejects the gas A2 into the lens barrel 142 by introducing the gas A2 from the third ejection port 104 into the space 71. The gas A2 introduced into the space 71 from the third ejection port 104 by the second ejection part 114 flows along the outer peripheral surface of the lens barrel 142 and is discharged to the outside of the space 71 from the second ejection port 106. The gas A2 discharged from the second ejection port 106 flows along the exit part 143 (light exit surface 14b) to protect the exit part 143.

[0075] In addition, between the edge of the opening on the emission section 143 side of the cover 70 and the objective lens section 14, a gap is formed directly below the third jet nozzle 104 in addition to the second jet nozzle 106, and the gas A2 can be discharged from the gap. However, a solid opposing wall section 72 of the cover 70 is provided in a portion opposing the portion of the cover 70 where the third jet nozzle 104 is provided (here, a position opposing the third jet nozzle 104). For this reason, the gas flow of the gas A2 introduced into the space 71 from the third jet nozzle 104 is dominated by the gas flow that circulates along the outer circumferential surface of the lens barrel 142, hits the opposing wall section 72, is guided by the opposing wall section 72 to the second jet nozzle 106 side, and is discharged from the second jet nozzle 106, rather than being discharged directly from the gap directly below the third jet nozzle 104. Therefore, in this embodiment, the gas flow of the gas A2 discharged from the end of the cover 70 on the side of the outlet 143 is generally regulated in the opening direction of the second outlet 106 (here, the negative Y-axis direction). However, the gas flow of the gas A2 discharged from the end of the cover 70 on the side of the outlet 143 is predominantly discharged directly from the gap directly below the third outlet 104, and may be regulated in the opposite direction (here, the positive Y-axis direction) to the opening direction of the second outlet 106 (here, the negative Y-axis direction). In this case, the gap directly below the third outlet 104 can be used as another second outlet. In other words, the second outlet may be capable of forming a gas flow of the gas A2 along the Y direction at the lower part of the outlet 143.

[0076] In this way, second ejection unit 114 introduces gas A2 from third ejection port 1004 into space 71 to eject the gas to barrel 142, and also ejects gas A2 from space 71 via second ejection port 106 to eject the gas to emission unit 143. Therefore, second ejection unit 114 also contributes to cooling of barrel 142 and condenser lens 141.

[0077] The second injection unit 114 is connected to the second flow rate adjustment unit 132 and injects the gas A2 sent via the second flow rate adjustment unit 132. The second flow rate adjustment unit 132 is connected to a gas supply source GA and adjusts the flow rate of the gas A2 in response to a signal from the control unit 9, thereby adjusting the flow rate of the gas A1 in the second injection unit 114. The second injection unit 114 is connected to a gas supply source GA common to the first injection units 111, 112, and 113. Therefore, in this embodiment, the first injection units 111, 112, and 113 and the second injection unit 114 inject the gases A1 and A2 from the same supply source (however, the gases A1 and A2 may be injected from different supply sources). In addition, a line AL that provides a flow path for gases A1 and A2 from the gas supply source GA to the first injection parts 111, 112, 113 and the second injection part 114 via the first flow rate adjustment part 131 and the second flow rate adjustment part 132 may be provided through a specified wall part of the housing 11 (see Figure 5).

[0078] Here, as shown in FIG. 7, the display 91 displays the injection status of the gases A1, A2 in the first injection mechanism 201 and the second injection mechanism 202, and can accept input from an operator to change the flow rates of the gases A1, A2 in the first injection mechanism 201 and the second injection mechanism 202.

[0079] More specifically, the display 91 can display a first display unit 911 and a second display unit 921. The first display unit 911 includes a function display unit 912 indicating that the first injection mechanism 201 has a cooling function for the lens barrel 142 and the condenser lens 141, an ON / OFF display unit 913 indicating whether the injection of the gas A1 from the first injection units 111, 112, and 113 is in an ON state (a state in which the flow rate is greater than 0) or an OFF state (a state in which the flow rate is 0), and a flow rate display unit 914 indicating the flow rate of the gas A1 in the first injection units 111, 112, and 113.

[0080] As an example, the display 91 accepts a touch operation of the flow rate display unit 914 by an operator, and outputs to the control unit 9 that an input for changing the flow rate of the gas A1 in the first ejection units 111, 112, and 113 has been accepted. The control unit 9 receives the input from the display 91 and can transmit a signal to the first flow rate adjustment unit 131 to change the flow rate of the gas A1 in the first ejection units 111, 112, and 113.

[0081] The second display unit 921 includes a function display unit 922 indicating that the second injection mechanism 202 has a protection function for the injection unit 143, an ON / OFF display unit 923 indicating whether the injection of gas A2 from the second injection unit 114 is in the ON or OFF state, and a flow rate display unit 924 indicating the flow rate of gas A2 in the second injection unit 114.

[0082] As an example, the display 91 outputs to the control unit 9 that an input for changing the flow rate of the gas A2 in the second injecting unit 114 has been received by accepting a touch operation of the flow rate display unit 924 by the operator. The control unit 9 can receive the input from the display 91 and transmit a signal to the second flow rate adjustment unit 132 to change the flow rate of the gas A2 in the second injecting unit 114. In this way, the display 91 functions as an input receiving unit that receives an input for changing the flow rates of the gases A1 and A2 in the first and second injecting mechanisms 201 and 202, respectively, independent of each other.

[0083] The first flow rate adjustment unit 131 and the second flow rate adjustment unit 132 may include, for example, an air regulator. The air regulator is a device for reducing the pressure of compressed air flowing in from an air compressor and adjusting it to an arbitrary pressure. As an example, if gases A1 and A2 flow from the compressor at 0.7 MPa, but the actually required pressure of gases A1 and A2 is 0.5 MPa, the pressure of gases A1 and A2 can be reduced from 0.7 MPa to 0.5 MPa by the air regulator. Since the electric air regulator can control the air pressure in proportion to an electric signal, it is possible to automatically control the flow rates of gases A1 and A2 in the first injection units 111, 112, and 113 and the second injection unit 114 in response to a signal from the control unit 9. [Example of laser processing method]

[0084] Next, an example of the laser processing method will be described. The laser processing method according to this embodiment can be implemented, for example, in the laser processing device 1. As shown in FIG. 8, processing conditions are first set (step S101). In step S101, as an example, the energy (output under the lens) of the laser light L emitted from the objective lens unit 14 is set according to the required processing of the target object W. In addition, in step S101, the energy (original laser output) of the laser light L in the light source 81, the frequency and pulse width of the laser light L, the modulation pattern to be displayed on the spatial light modulator 36, and the like can also be set.

[0085] Next, prior to the subsequent calibration of the attenuator 32 and the like (step S103), the flow rates of the gas A1 and the gas A2 in the first injection parts 111, 112, 113 and the second injection part 114 are adjusted (step S102). More specifically, in step S102, the control part 9 controls the first flow rate adjustment part 131 to increase the flow rate of the gas A1 in the first injection parts 111, 112, 113 (for example, to the ON state), and starts cooling the lens barrel 142 and the condenser lens 141 in the lens barrel 142 by the injection of the gas A1 from the first injection parts 111, 112, 113. Also, in step S102, the control part 9 controls the second flow rate adjustment part 132 to decrease the flow rate of the gas A2 in the second injection part 114 (for example, to the OFF state).

[0086] Thereafter, calibration of the attenuator 32 and the like is performed (step S103). In step S103, first, as shown in Fig. 9, a power meter Mp is placed so as to face the emission part 143 of the laser light L in the objective lens part 14. Next, in step S103, the control part 9 controls the light source 81 to emit the laser light L from the emission part 143, and performs a power measurement process to measure the power of the laser light L by the power meter Mp placed opposite the emission part 143.

[0087] As an example, the attenuator 32 includes a λ / 2 wave plate and a polarizing beam splitter, and the control unit 9 changes the rotation angle of the λ / 2 wave plate while irradiating the power meter Mp with the laser light L, and obtains the attenuation ratio for each rotation angle of the power measured by the power meter Mp. Then, the control unit 9 derives an approximation formula for a graph of the rotation angle of the λ / 2 wave plate and the attenuation ratio.

[0088] The power meter Mp is, for example, a thermal sensor, which is capable of measuring the average power of the laser light L with high accuracy. The thermopile sensor absorbs light with an absorber and converts it into heat. The thermal sensor performs measurement using a thermocouple of a thermopile. Therefore, if the gas A2 for protecting the objective lens unit 14 hits the power meter Mp, the heat of the power meter Mp may change, which may cause a measurement error.

[0089] In contrast to this, here, prior to the calibration (step S103) using the power meter Mp, the flow rate of the gas A2 in the second injector 114 is reduced in step S102. This prevents measurement errors caused by the gas A2 hitting the power meter Mp. In this manner, the control unit 9 controls the second flow rate adjustment unit 132 to execute a flow rate reduction process for reducing the flow rate of the gas A2 in the second injector 114 before (or during) the power measurement process.

[0090] In step S103, a power meter Mp similarly arranged opposite the exit portion 143 may be used to perform calibration of other elements, such as pattern calibration of the spatial light modulator 36, to determine the pattern transmittance of the spatial light modulator 36 depending on whether or not a pattern is displayed on the spatial light modulator 36.

[0091] In the next step, a power check is performed (step S104). In step S104, it is checked whether the output under the lens set in step S101 is actually being generated. The output under the objective lens is determined by the product of the original laser output, the attenuation ratio in the attenuator 32, and the pattern transmittance in the spatial light modulator 36. In step S104, the control unit 9 measures the power of the laser light L by the power meter Mp, and determines whether the variation in the measurement result with respect to the output under the objective lens set in step S101 is within a range acceptable to the user.

[0092] If the result of the power check in step S104 indicates that the variation in the measurement result with respect to the output under the objective lens set in step S101 is outside the allowable range (NG case), the control unit 9 can notify an error, for example, using the display 91. Examples of cases in which the power check is NG include possible approximation errors during calibration of the attenuator 32 and a decrease in the original laser output. Therefore, stability can be improved by performing a power check immediately before processing.

[0093] Subsequently, the object W is processed. More specifically, in the next step, the object W is aligned (step S105). In step S105, the lines WL of the object W are matched with the processing progress angle. To achieve this, in step S105, while the object W is being imaged by an alignment camera, for example, the support part 7 supporting the object W is rotated about an axis parallel to the Z direction, thereby placing the object W in a state in which the multiple lines WL of the object W extend along the X direction and are arranged in the Y direction intersecting the X direction.

[0094] Subsequently, the height is set (step S106). In step S106, the moving mechanism 6 moves the laser processing head 10A in the Z direction, and the focal point of the distance measuring light L20 in the distance measuring unit 100 is aligned with the surface of the object W on the objective lens unit 14 side (the incident surface of the laser light L). Then, at the position where the focal point of the distance measuring light L20 is aligned with the surface of the object W on the objective lens unit 14 side, a reference voltage for autofocus is obtained. The reference voltage is a voltage applied by the driving unit 18, and is a voltage that is a reference for the amount of movement of the objective lens unit 14.

[0095] Next, prior to actual processing (step S108), the flow rates of gas A1 and gas A2 in the first ejection parts 111, 112, 113 and the second ejection part 114 are adjusted (step S107). More specifically, in step S107, the control part 9 controls the second flow rate adjustment part 132 to increase the flow rate of gas A2 in the second ejection part 114 (for example, to the ON state), and starts protecting the emission part 143 of the objective lens part 14 by ejecting gas A2 from the second ejection part 114.

[0096] In addition, in step S107, the control unit 9 controls the second flow rate adjustment unit 132 to maintain the flow rate of gas A2 in the second injection unit 114 adjusted, for example, in step S102 (for example, to maintain the ON state), and cools the telescope tube 142 and the focusing lens 141 in the telescope tube 142 by injecting gas A1 from the first injection units 111, 112, and 113.

[0097] Next, the object W is processed (step S108). In step S108, first, as shown in Fig. 10, the object W is placed so as to face the emission part 143 of the laser light L in the objective lens unit 14. As shown in Fig. 11, a plurality of lines WL extending in one direction are set on the object W, and in step S105, the object W is placed so that the plurality of lines WL extend along the X direction and are arranged in the Y direction intersecting the X direction.

[0098] Thereafter, in step S108, the control unit 9 controls the light source 81 to emit the laser light L from the emission unit 143, thereby executing a processing process for processing the object W arranged opposite the emission unit 143. Specifically, as shown in FIG. 12, the control unit 9 executes a scanning process as the processing process, in which the laser light L is scanned on the object W while moving the focal point P of the laser light L along one line WL along the X direction. As a result, a modified region Mr serving as a starting point for cutting is formed on the object W. The control unit 9 executes the scanning process multiple times from one line WL on one side to the other line WL on the Y direction. The laser processing is completed by executing the scanning process on all lines WL of the object W.

[0099] In this way, the control unit 9 executes a flow rate increasing process that controls the second flow rate adjusting unit 132 to increase the flow rate of gas A2 in the second ejection unit 114 after the flow rate decreasing process and before (or during) the processing process. In addition, the control unit 9 executes a cooling process that controls the first flow rate adjusting unit 131 to cool the lens barrel 142 and the condenser lens 141 in the lens barrel 142 by ejecting gas A1 from the first ejection units 111, 112, and 113 before (or during) the power measurement process and the processing process.

[0100] That is, the control unit 9 reduces the amount of gas A2 injected from the second injection unit 114 when the power meter Mp is arranged opposite the emission unit 143 of the objective lens unit 14, and increases the amount of gas A2 injected from the second injection unit 114 when the laser light L is emitted from the objective lens unit 14 to process the target object W. Furthermore, the control unit 9 performs cooling with the gas A1 from the first injection units 111, 112, and 113 when the laser light L is emitted from the objective lens unit 14, regardless of whether the power meter Mp is arranged opposite the emission unit 143 of the objective lens unit 14 or the target object W is arranged opposite. This makes it possible to simultaneously suppress measurement errors of the power meter Mp and suppress the influence of a temperature rise of the condenser lens 141 on the processing result.

[0101] When neither the power meter Mp nor the object W is disposed facing the emission part 143 of the objective lens part 14, for example, when the alignment step S105 or the height setting step 106 is performed, the injection amount of the gas A2 from the second injection part 114 may or may not be reduced. When the laser light L is not emitted from the objective lens part 14, for example, when the alignment step S105 or the height setting step 106 is performed, cooling with the gas A1 from the first injection parts 111, 112, and 113 may or may not be performed.

[0102] Here, the second ejection nozzle 106 is open in a direction intersecting with the X direction, which is the traveling direction (processing proceeding direction) of the focal point P of the laser light L in step S108 (processing treatment). This makes it possible to blow away debris generated during processing of the target object W in a direction intersecting with the processing proceeding direction by the gas A2 ejected to the emission part 143 of the laser light L via the second ejection nozzle 106.

[0103] Furthermore, in step S108 (processing), as described above, the laser light L is scanned multiple times from one line WL on one side in the Y direction to the other line WL on the other side (here, in the positive direction of the Y axis). In contrast, the second ejection port 106 opens in a direction from the other side to one side in the Y direction (here, the negative direction of the Y axis). As a result, the gas A2 ejected from the second ejection port 106 to the emission part 143 of the laser light L blows debris from the unprocessed region R2 of the target object W toward the processed region R1, thereby preventing debris from scattering in the unprocessed region R2 of the target object W.

[0104] In step S108 (processing), a scanning process may be performed in which the laser light L is scanned at a plurality of positions in the Z direction, which is the thickness direction of the object W. In this case, there is a feature that debris is more likely to be generated when the laser light L is scanned at a position (shallower position) closer to the incident surface of the laser light L in the Z direction of the object W. Therefore, the control unit 9 can control the second flow rate adjustment unit 132 so that the injection amount of the gas A2 from the second injection unit 114 increases as the position (position where the scanning process is performed) where the focal point P of the laser light L in the Z direction of the object W is aligned is closer to the incident surface of the laser light L. As an example, when the control unit 9 performs the scanning process by aligning the focal point P with each of a first position in the Z direction of the object W and a second position closer to the incident surface than the first position in the processing process, the control unit 9 can control the second flow rate adjustment unit 132 so that the injection amount of the gas A2 is relatively small during the scanning process at the deeper first position and the injection amount of the gas A2 is relatively large during the scanning process at the shallower second position. [Actions and Effects]

[0105] Next, the operation and effect of the laser processing device 1 according to this embodiment will be described. In the laser processing device 1 according to this embodiment, the laser processing head 10A has an objective lens unit 14 including a condenser lens 141 and a lens barrel 142 that holds the condenser lens 141. A gas A1 is injected into the lens barrel 142 by a first injection mechanism 201, and a gas is injected into an emission part 143 of the laser light L in the objective lens unit 14 by a second injection mechanism 202. More specifically, the first injection mechanism 201 includes first injection ports 101, 102, and 103 that communicate with a space 71 between the cover 70 provided on the lens barrel 142 and the lens barrel 142, and first injection parts 111, 112, and 113 that introduce the gas A1 from the first injection ports 101, 102, and 103 into the space 71 to inject the gas A1 into the lens barrel 142.

[0106] Further, the second injection mechanism 202 includes a second injection port 106 and a second injection unit 114 that injects gas A2 from the second injection port 106 to the emission unit 143 of the laser light L. This allows cooling of the lens barrel 142 and the condenser lens 141 in the lens barrel 142, and protects the emission unit 143 of the laser light L from adhesion of debris. In particular, the first injection mechanism 201 includes a first flow rate adjustment unit 131 for adjusting the flow rate of gas A1 of the first injection units 111, 112, and 113, and the second injection mechanism 202 includes a second flow rate adjustment unit 132 for adjusting the flow rate of gas A2 of the second injection unit 114. Therefore, the supply of gas A2 to the emission unit 143 of the laser light L by the second injection unit 114 can be adjusted independently of the supply of gas A1 by the first injection units 111, 112, and 113.

[0107] The second injection port 106 opens in a direction (here, the Y direction) intersecting the optical axis Lx of the laser light L in the objective lens section 14. Therefore, when the second injection section 114 is injecting the gas A2, the gas A2 injected from the second injection port 106 flows directly in the optical axis direction, and is prevented from hitting an object or a power meter arranged opposite the condenser lens unit.

[0108] In the laser processing device 1 according to the present embodiment, the second injection mechanism 202 includes a third injection port 104 provided in the cover 70 so as to communicate with the space 71. The second injection unit 114 introduces the gas A2 from the third injection port 104 into the space 71 to inject the gas A2 into the lens barrel 142, and also ejects the gas A2 from the space 71 through the second injection port 106 to eject the gas A2 into the emission unit 143. Therefore, the gas introduced into the space 71 from the third injection port 104 communicating with the space 71 between the cover 70 and the lens barrel 142 and ejected into the lens barrel 142 is ejected from the space 71 through the second injection port 106 and ejected into the emission unit. Therefore, the gas A2 supplied to the emission unit 143 of the laser light L is given a cooling function for the lens barrel 142 and the condenser lens 141 in the lens barrel 142, making it possible to perform more effective cooling.

[0109] In the laser processing device 1 according to this embodiment, the first injectors 111, 112, 113 and the second injector 114 inject the gases A1 and A2 from the same gas supply source GA. This makes it possible to cool the lens barrel 142 and the condenser lens 141 in the lens barrel 142 and protect the emission part 143 of the laser light L with a simpler configuration.

[0110] The laser processing apparatus 1 according to the present embodiment also includes a control unit 9. The control unit 9 performs a power measurement process for emitting the laser light L from the emission unit 143 and measuring the power of the laser light L using a power meter Mp arranged opposite the emission unit 143, and a flow rate reduction process for controlling the second flow rate adjustment unit 132 to reduce the flow rate of the gas A2 in the second injection unit 114 before the power measurement process. Thus, when the power of the laser light L is measured using the power meter Mp arranged opposite the emission unit 143 of the laser light L, the flow rate of the gas A2 injected into the emission unit 143 is reduced. This suppresses the occurrence of measurement errors caused by the gas A2 hitting the power meter Mp and cooling the power meter Mp.

[0111] In the laser processing device 1 according to the present embodiment, the control unit 9 performs a processing process of processing the object W arranged opposite the emission unit 143 by emitting the laser light L from the emission unit 143 after the flow rate reduction process, and a flow rate increase process of increasing the flow rate of the gas A2 in the second injection unit 114 by controlling the second flow rate adjustment unit 132 after the flow rate reduction process and before the processing process is performed. Thus, during the laser processing of the object W arranged opposite the emission unit 143, the flow rate of the gas A2 injected into the emission unit 143 is increased. This ensures that the emission unit 143 is protected during the laser processing.

[0112] Furthermore, in the laser processing apparatus 1 according to this embodiment, the control unit 9 controls the first flow rate adjustment unit 131 to perform a cooling process to cool the lens barrel 142 and the condenser lens 141 in the lens barrel 142 by injecting the gas A1 from the first injectors 111, 112, and 113 before each of the power measurement process and the processing process. Thus, both during power measurement by the power meter Mp and during laser processing of the target object W, the lens barrel 142 and the condenser lens 141 in the lens barrel 142 are cooled.

[0113] Thus, in the laser processing apparatus 1 according to the present embodiment, during power measurement by the power meter Mp (for example, during calibration in step S103), the amount of gas A2 injected to protect the emission part 143 of the objective lens unit 14 is reduced, while the cooling of the lens barrel 142 and the condenser lens 141 in the lens barrel 142 by the gas A1 is maintained. If cooling of the condenser lens (objective lens) is stopped during calibration to suppress power measurement errors caused by gas hitting the power meter Mp as in the conventional case, the condenser lens is affected by heat, and a problem occurs in that the processing position shifts significantly in the XY plane including the X and Y directions during subsequent laser processing of the target object.

[0114] In this case, the deviation of the processing position in the XY plane during laser processing reaches about 11.5 μm when the output under the lens is 4 W and the calibration takes 20 minutes, for example. In contrast, as in the laser processing device 1 according to the present embodiment, the amount of gas A2 for protecting the emission part 143 of the objective lens part 14 is reduced during calibration, while the cooling of the lens barrel 142 and the condenser lens 141 in the lens barrel 142 by gas A1 is maintained, so that the deviation of the processing position in the XY plane during laser processing can be suppressed to less than 1 μm, even when the output under the lens is 4 W and the calibration takes 20 minutes. The flow rate of the cooling gas A1 at this time is 25 L / min, for example.

[0115] In the laser processing apparatus 1 according to the present embodiment, the control unit 9 performs a scanning process in which the laser light L is scanned on the object W while moving the focal point P of the laser light L along one line WL along the X direction, in a state in which the object W is arranged so that a plurality of lines WL extend along the X direction and are arranged in the Y direction, as a processing process. The second ejection port 106 opens in a direction intersecting the X direction (here, the Y direction). For this reason, the gas A2 ejected through the second ejection port 106 can blow away debris generated during laser processing of the object W in a direction intersecting the processing proceeding direction (X direction).

[0116] Furthermore, in the laser processing apparatus 1 according to this embodiment, the control unit 9 performs the scanning process multiple times from one line WL on one side in the Y direction to the other line WL on the other side in the Y direction (here, in the positive direction of the Y axis). The second jet nozzle 106 opens in a direction from the other side to one side in the Y direction (here, in the negative direction of the Y axis). Therefore, the gas A2 jetted through the second jet nozzle 106 blows debris generated during laser processing of the target object W from the unprocessed region R2 of the target object W toward the processed region R1, thereby preventing the debris from scattering in the unprocessed region R2 of the target object W.

[0117] In addition, when the flow rates of the gases A1 and A2 are increased, there is a risk that dust in the air may fly around the objective lens unit 14, or that the device structure of the target W may be damaged. In this case, therefore, the flow rates of the gases A1 and A2 can also be appropriately set when setting the processing conditions in step S101. That is, before the processing (for example, in step S101), the control unit 9 can receive an input for flow rate adjustment of the gases A1 and A2 according to the type of device the target W has, the laser source output, etc., via the flow rate display units 914 and 924 of the display 91, and control the first flow rate adjustment unit 131 and the second flow rate adjustment unit 132 so that the flow rates of the gases A1 and A2 in the first ejection units 111, 112, and 113 and the second ejection unit 114 become the received flow rates.

[0118] As an example, when the object W has a surface on which a device layer is provided and a back surface opposite to the surface, the surface is the incident surface of the laser light L, and the back surface has a beveled portion, the flow rate of the protective gas A2 can be increased, for example, by about 5 L / min from the optimal flow rate, which is the initial setting amount. As another example, when the back surface of the object W has been ground and the back surface is the incident surface of the laser light L, the flow rate of the protective gas A2 can be reduced, for example, by about 5 L / min from the optimal flow rate, which is the initial setting amount. As yet another example, when the object W has a fragile structure such as a MEMS (Micro Electro Mechanical Systems), the flow rate of the protective gas A2 can be reduced, for example, by about 10 L / min from the optimal flow rate, which is the initial setting amount.

[0119] Alternatively, when the laser output is a reference value of, for example, about 8 W, the flow rate of the cooling gas A1 is set to an optimum flow rate, which is an initial setting amount, and when the laser output is a value of, for example, about 16 W, which is larger than the reference value, the flow rate of the cooling gas A1 can be increased, for example, by about 5 L / min from the optimum flow rate, which is an initial setting amount. On the other hand, when the laser output is a value of, for example, about 2 W, which is smaller than the reference value, the flow rate of the cooling gas A1 can be decreased, for example, by about 5 L / min from the optimum flow rate, which is an initial setting amount. [Variations]

[0120] The above embodiment has been described as one form of the laser processing device according to the present invention. Therefore, the present invention is not limited to the above embodiment and can be modified. Next, modified examples will be described.

[0121] The laser processing apparatus 1 according to the above embodiment is provided with the first jetting mechanism 201 including a plurality of (three in the illustrated example) first jetting sections 111, 112, 113. However, as shown in Fig. 13, the laser processing apparatus 1 may be provided with a first jetting mechanism 201A including only one first jetting section 111, instead of the first jetting mechanism 201.

[0122] Alternatively, as shown in Fig. 14, the laser processing apparatus 1 may include a second ejection mechanism 202A instead of the second ejection mechanism 202. In the example shown in Fig. 14, the emission part 143 of the laser light L in the objective lens part 14 has a protective cover 150. The protective cover 150 covers the light emission surface 14b of the laser light L of the condenser lens 141 when viewed from the Z direction. In particular, in the illustrated example, the protective cover 150 is provided on the cover 70 so as to block the opening on the emission part 143 side of the cover 70. Therefore, the space 71 of the cover 70 is closed at the end part on the emission part 143 side of the cover 70.

[0123] In the second ejection mechanism 202A, the second ejection port 106 is provided outside the space 71 of the cover 70, and the second ejection unit 114 is fitted into the second ejection port 106. The second ejection port 106 opens in a direction intersecting the optical axis Lx of the laser light L in the objective lens unit 14 (here, the Y direction). Thus, here, the second ejection port 106 is provided in the cover 70 separated from the space 71, and the second ejection unit 114 ejects the gas A2 from the second ejection port 106 to the emission unit 143 (protective cover 150) without passing through the space 71. The gas A2 ejected from the second ejection unit 114 is caused to flow along the protective cover 150. According to this modification, the light emission surface 14b is reliably protected. In addition, it is possible to clearly distinguish between the cooling of the lens barrel 142 and the condenser lens 141 by the injection of gas A1 from the first injection mechanism 201 and the protection of the emission part 143 of the laser light L by the injection of gas A2 from the second injection mechanism 202A.

[0124] 15, the laser processing apparatus 1 may be provided with a first jetting mechanism 201B instead of the first jetting mechanism 201, a second jetting mechanism 202A instead of the second jetting mechanism 202, and may further be provided with a suction unit 160. In the example of FIG. 15, the emission unit 143 has a protective cover 150.

[0125] In the example of FIG. 15, the cover 70 has an annular edge 75 formed at the end on the entrance pupil plane 14a side so as to surround the outer circumferential surface of the lens barrel 142. The edge 75 extends along the XY plane. The first ejection mechanism 201B is provided on the edge 75 so as to communicate with the space 71, and includes a plurality of first ejection ports 101 that open in the Z direction. In the first ejection mechanism 201B, a first ejection unit 111 is fitted in a gap between the end of the cover 70 on the entrance pupil plane 14a side and the end of the lens barrel 142 on the entrance pupil plane 14a side. The first ejection unit 111 ejects the gas A1 along a direction (here, the Y direction) that intersects with the Z direction. The gas A1 ejected from the first ejection unit 111 is introduced into the space 71 from the plurality of first ejection ports 101, and flows in the Z direction along the outer circumferential surface of the lens barrel 142. Gas A1 that has flowed along the lens barrel 142 is discharged from outlet 108 that is provided on the emission part 143 side from the center of the cover 70 in the Z direction, for example. In this way, the first injection port 101 may be open in the Z direction. In this case, since the cooling efficiency can be improved, the flow rate of the cooling gas A1 can be reduced while suppressing heat generation of the condenser lens 141.

[0126] 15, the opening of the cover 70 on the side of the ejection part 143 is closed by the protective cover 150. Therefore, the gas A1 introduced from the first ejection port 101 into the space 71 and flowing along the Z direction is prevented from being guided in the Z direction from the end of the cover 70 on the side of the ejection part 143 and hitting, for example, the power meter Mp. Furthermore, the suction part 160 is disposed at a position facing the second ejection part 114 of the second ejection mechanism 202A. This allows the gas A2 ejected from the second ejection part 114 and scattered objects such as debris scattered by the gas A2 to be sucked in by the suction part 160.

[0127] Furthermore, the elements according to the above-described embodiment and each modified example can be appropriately adopted in the laser processing device 1. For example, a suction unit 160 may be adopted in the laser processing device 1 according to the above-described embodiment.

[0128] In addition, in the above embodiment and each modified example, the case where there is one second injector 114 that injects the protective gas A2 has been exemplified, but there may be provided a plurality of second injectors 114. When a plurality of second injectors 114 are provided, the plurality of second injectors 114 may be arranged in the Z direction. [Explanation of symbols]

[0129] 1...laser processing apparatus, 9...control unit, 14...objective lens unit (condensing lens unit), 14b...light emission surface (emission surface), 70...cover, 71...space, 101, 102, 103...first nozzle, 104...third nozzle, 106...second nozzle, 111, 112, 113...first nozzle, 114...second nozzle, 131...first flow rate adjustment unit, 132...second flow rate adjustment unit, 141...condensing lens, 142...lens barrel, 143...emission unit, 150...protective cover, 160...suction unit, A1, A2...gas, L...laser light, Lx...optical axis, Mp...power meter, W...target, WL...line.

Claims

1. A laser processing apparatus that irradiates a target object with laser light to process the target object, A laser processing head having a condenser lens unit including a condenser lens for condensing the laser light toward the object and a lens barrel for holding the condenser lens therein; a cover provided on the lens barrel so as to cover the lens barrel while forming a space between the lens barrel and the cover; a first injection mechanism for injecting gas into the lens barrel; a second injection mechanism for injecting gas at least toward an emission portion of the laser light in the condenser lens unit; Equipped with the first injection mechanism includes: a first injection port provided in the cover to communicate with the space; a first injection unit that injects gas into the lens barrel by introducing gas from the first injection port into the space; and a first flow rate adjustment unit that adjusts a flow rate of gas in the first injection unit; the second injection mechanism includes a second injection port provided in the cover and opening in a direction intersecting an optical axis of the laser light in the condenser lens unit, a second injection unit that injects gas from the second injection port to the emission unit, and a second flow rate adjustment unit that adjusts a flow rate of the gas in the second injection unit. Laser processing equipment.

2. the second injection mechanism includes a third injection port provided in the cover so as to communicate with the space, the second injection unit introduces gas into the space from the third injection port to inject the gas into the lens barrel, and also ejects the gas from the space via the second injection port to inject the gas into the emission unit. The laser processing device according to claim 1.

3. The second injection port is provided in the cover and separated from the space, The second injection section injects gas from the second injection port to the emission section without passing through the space. The laser processing device according to claim 1.

4. The first injection unit and the second injection unit inject gas from the same supply source. The laser processing device according to claim 1.

5. The emission unit includes a protective cover that covers an emission surface of the laser light of the condenser lens. The laser processing device according to claim 1.

6. A control unit is provided, The control unit is a power measurement process of emitting a laser beam from the emission unit and measuring the power of the laser beam by a power meter disposed opposite the emission unit; a flow rate reduction process of controlling the second flow rate adjustment unit to reduce a flow rate of the gas in the second injection unit before or during the power measurement process; To carry out 2. The laser processing apparatus according to claim 1.

7. The control unit is a processing process for processing the object disposed opposite the emission part by emitting the laser light from the emission part after the flow rate reduction process; a flow rate increasing process that is performed after the flow rate decreasing process and before or during the processing process, by controlling the second flow rate adjusting unit to increase the flow rate of the gas in the second injection unit; To carry out The laser processing apparatus according to claim 6.

8. the control unit controls the first flow rate adjustment unit to perform a cooling process of cooling the lens barrel by injecting gas from the first injection unit before or during each of the power measurement process and the processing process. The laser processing apparatus according to claim 7.

9. The object has a plurality of lines extending in one direction set thereon, the control unit, in a state in which the object is disposed such that the plurality of lines extend along an X direction and are arranged in a Y direction intersecting the X direction, performs, as the processing process, a scanning process of scanning the object with the laser light while moving a focusing point of the laser light along one of the lines along the X direction; The second injection port is open in a direction intersecting the X direction.

9. The laser processing apparatus according to claim 7 or 8.

10. The control unit performs the scanning process a plurality of times from the line on one side to the line on the other side in the Y direction, The second injection port is open in a direction from the other side to the one side in the Y direction. The laser processing apparatus according to claim 9.

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