Laser processing equipment

Abstract

To provide a laser processing device capable of suppressing attachment of foreign matters to an optical component.SOLUTION: A laser processing device for processing an object to be processed includes a holding table for holding the object to be processed and a laser beam irradiation unit which irradiates the object to be processed which is held by the holding table with laser beams. The laser beam irradiation unit has a laser oscillator, a light condenser which condenses laser beams emitted from the laser oscillator, an optical component which guides laser beams from the laser oscillator to the light condenser, a housing section which houses the optical component and an ionizer which is provided on inner parts of the housing section and catches foreign matters existing on the inner parts of the housing section.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus for processing a workpiece by irradiating a laser beam.

Background Art

[0002] In the manufacturing process of device chips, a wafer in which devices are formed in a plurality of regions partitioned by a plurality of streets (lines to be divided) arranged in a grid pattern is used. By dividing this wafer along the streets and fragmenting it, device chips having devices are obtained. The device chips are incorporated into various electronic devices such as mobile phones and personal computers.

[0003] For dividing a wafer, a cutting apparatus that cuts a workpiece with an annular cutting blade is used. In recent years, development of a process using laser processing by a laser processing apparatus for dividing a wafer has also been advanced. The laser processing apparatus includes a holding table for holding a workpiece and a laser beam irradiation unit for irradiating a laser beam. By holding the wafer on the holding table and irradiating the wafer with a laser beam from the laser beam irradiation unit, laser processing is performed on the wafer.

[0004] For example, Patent Document 1 discloses a method of removing a low dielectric constant insulating film formed on a wafer along a street by irradiating a laser beam before cutting the wafer with a cutting blade. When using this method, when cutting the cutting blade along the street into the wafer, it is possible to avoid contact of the high-speed rotating cutting blade with the low dielectric constant insulating film, and peeling of the low dielectric constant insulating film is prevented.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] The laser beam irradiation unit mounted in a laser processing machine is equipped with an optical system that guides the laser beam emitted from the laser oscillator to the workpiece. The optical system consists of various optical components, such as mirrors that reflect the laser beam in a predetermined direction and a focuser that concentrates the laser beam.

[0007] If foreign matter such as particles (dust, etc.) adheres to the optical components of an optical system, various problems may occur, such as distortion of the laser beam shape, shift in the focusing position, and a decrease in output. Therefore, the laser beam irradiation unit is provided with a housing for the optical system, and the optical components are arranged inside the housing so as to be isolated from the outside. This prevents particles from the atmosphere from adhering to the optical components.

[0008] However, components other than the optical components that make up the optical system are also placed inside the housing. For example, holders that hold the optical components and actuators such as motors that control the position or angle of the optical components are housed in the housing along with the optical components. Therefore, even if the inside of the housing is isolated and sealed, outgassing released from holders and actuators may adhere to the optical components and contaminate them. In addition, during maintenance of the laser processing equipment, the containers that make up the housing are opened in order to adjust, replace, or clean the optical components. At that time, particles may enter and accumulate inside the housing and adhere to the optical components after maintenance. Therefore, even if the optical system of the laser beam irradiation unit is housed in a housing, it is difficult to completely prevent foreign matter from adhering to the optical components.

[0009] This invention has been made in view of the above problems, and aims to provide a laser processing apparatus capable of suppressing the adhesion of foreign matter to optical components. [Means for solving the problem]

[0010] According to one aspect of the present invention, a laser processing apparatus for processing a workpiece is provided, comprising: a holding table for holding the workpiece; and a laser beam irradiation unit for irradiating the workpiece held by the holding table with a laser beam, wherein the laser beam irradiation unit comprises: a laser oscillator; a concentrator for focusing the laser beam emitted from the laser oscillator; an optical component for guiding the laser beam from the laser oscillator to the concentrator; a housing for housing the optical component; and an ionizer provided inside the housing for capturing foreign matter present inside the housing.

[0011] Preferably, the ionizer is of the windless type. Furthermore, preferably, the laser processing apparatus further includes a determination unit that determines the cleanliness of the inside of the containment based on the amount of ions generated by the ionizer. [Effects of the Invention]

[0012] A laser processing apparatus according to one aspect of the present invention includes a housing for accommodating optical components of a laser beam irradiation unit, and an ionizer for capturing foreign matter is installed inside the housing. This makes it difficult for foreign matter present inside the housing to adhere to the optical components, and enables the laser beam to be irradiated onto the workpiece under appropriate conditions. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view showing a laser processing machine. [Figure 2] This is a perspective view showing the workpiece. [Figure 3] This is a partial cross-sectional side view showing a laser processing device. [Figure 4] This graph shows the relationship between the duration of ion generation and the amount of ions generated. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment of one aspect of the present invention will be described with reference to the attached drawings. First, an example of the configuration of a laser processing apparatus according to this embodiment will be described. Figure 1 is a perspective view showing the laser processing apparatus 2. In Figure 1, the X-axis direction (processing feed direction, first horizontal direction, left-right direction) and the Y-axis direction (indexing feed direction, second horizontal direction, front-back direction) are perpendicular to each other. Also, the Z-axis direction (vertical direction, height direction, up-down direction) is perpendicular to the X-axis direction and the Y-axis direction.

[0015] The laser processing apparatus 2 includes a base 4 that supports each component of the laser processing apparatus 2. The upper surface of the base 4 is a flat surface that is generally parallel to the horizontal plane (XY plane), and a moving unit (moving mechanism) 6 is provided on the upper surface of the base 4. The moving unit 6 includes a Y-axis moving unit (indexing feed unit) 8, an X-axis moving unit (processing feed unit) 18, and a Z-axis moving unit 32.

[0016] The Y-axis movement unit 8 includes a pair of Y-axis guide rails 10 arranged along the Y-axis direction on the upper surface of the base 4. A flat Y-axis movement table 12 is mounted on the pair of Y-axis guide rails 10 so as to be slidable along the Y-axis guide rails 10.

[0017] A nut (not shown) is provided on the underside (bottom) of the Y-axis moving table 12. A Y-axis ball screw 14, which is positioned along the Y-axis direction between a pair of Y-axis guide rails 10, is screwed into this nut. A Y-axis pulse motor 16, which rotates the Y-axis ball screw 14, is connected to the end of the Y-axis ball screw 14. When the Y-axis pulse motor 16 rotates the Y-axis ball screw 14, the Y-axis moving table 12 moves along the Y-axis guide rails 10 in the Y-axis direction.

[0018] The X-axis movement unit 18 includes a pair of X-axis guide rails 20 arranged along the X-axis direction on the surface (upper surface) side of the Y-axis movement table 12. A flat X-axis movement table 22 is mounted on the pair of X-axis guide rails 20 so as to be slidable along the X-axis guide rails 20.

[0019] On the back surface (lower surface) side of the X-axis moving table 22, a nut portion (not shown) is provided. An X-axis ball screw 24 arranged along the X-axis direction is screwed into this nut portion between a pair of X-axis guide rails 20. Further, an X-axis pulse motor 26 for rotating the X-axis ball screw 24 is connected to an end portion of the X-axis ball screw 24. When the X-axis ball screw 24 is rotated by the X-axis pulse motor 26, the X-axis moving table 22 moves in the X-axis direction along the X-axis guide rails 20.

[0020] A holding table (chuck table) 28 is connected to the Y-axis moving unit 8 and the X-axis moving unit 18. The holding table 28 holds a workpiece 11 (see FIG. 2), which is an object to be laser-processed by the laser processing apparatus 2. The holding table 28 is installed on the surface (upper surface) of the X-axis moving table 22. Further, a plurality of clamps 30 for gripping and fixing an annular frame 17 (see FIG. 2) that supports the workpiece 11 are provided around the holding table 28.

[0021] FIG. 2 is a perspective view showing the workpiece 11. For example, the workpiece 11 is a disk-shaped wafer made of a semiconductor material such as single crystal silicon, and includes surfaces 11a and 11b that are generally parallel to each other. The workpiece 11 is partitioned into a plurality of rectangular regions by a plurality of streets (division planned lines) 13 arranged in a grid pattern so as to intersect each other. Further, devices 15 such as IC (Integrated Circuit), LSI (Large Scale Integration), LED (Light Emitting Diode), and MEMS (Micro Electro Mechanical Systems) devices are formed on the surface 11a side of the plurality of regions partitioned by the streets 13.

[0022] However, there are no restrictions on the type, material, shape, structure, size, etc. of the workpiece 11. For example, the workpiece 11 may be a substrate (wafer) made of a semiconductor other than silicon (such as GaAs, InP, GaN, SiC, etc.), sapphire, glass, ceramics, resin, metal, etc. Also, there are no restrictions on the type, number, shape, structure, size, arrangement, etc. of the devices 15, and the devices 15 may not be formed on the workpiece 11.

[0023] When processing the workpiece 11 with the laser processing apparatus 2 (see FIG. 1), for the convenience of handling (transporting, holding, etc.) the workpiece 11, the workpiece 11 is supported by an annular frame 17. The frame 17 is made of a metal such as SUS (stainless steel), and a circular opening 17a penetrating the frame 17 in the thickness direction is provided at the center of the frame 17. Note that the diameter of the opening 17a is larger than the diameter of the workpiece 11.

[0024] A circular sheet 19 is fixed to the workpiece 11 and the frame 17. For example, as the sheet 19, a tape including a film-like base material formed in a circular shape and an adhesive layer (paste layer) provided on the base material is used. The base material is made of a resin such as polyolefin, polyvinyl chloride, polyethylene terephthalate, etc. Also, the adhesive layer is made of an epoxy-based, acrylic-based, or rubber-based adhesive, etc. Note that the adhesive layer may be an ultraviolet curable resin.

[0025] With the workpiece 11 disposed inside the opening 17a of the frame 17, the central portion of the sheet 19 is attached to the back surface 11b side of the workpiece 11, and the outer peripheral portion of the sheet 19 is attached to the frame 17. Thereby, the workpiece 11 is supported by the frame 17 via the sheet 19.

[0026] As shown in FIG. 1, the upper surface of the holding table 28 is a flat surface substantially parallel to the horizontal plane (XY plane), and constitutes a holding surface 28a for holding the workpiece 11. The holding surface 28a is connected to a suction source (not shown) such as an ejector via a flow path (not shown), a valve (not shown), etc. formed inside the holding table 28.

[0027] When the Y-axis moving table 12 is moved along the Y-axis, the holding table 28 moves along the Y-axis. Similarly, when the X-axis moving table 22 is moved along the X-axis, the holding table 28 moves along the X-axis. Furthermore, the holding table 28 is connected to a rotational drive source (not shown), such as a motor, which rotates the holding table 28 around a rotation axis that is roughly parallel to the Z-axis.

[0028] A Z-axis movement unit 32 is provided at the rear end of the base 4 (behind the Y-axis movement unit 8, the X-axis movement unit 18, and the holding table 28). The Z-axis movement unit 32 includes a support structure 34 positioned on the upper surface of the base 4. The support structure 34 includes a rectangular parallelepiped base 34a fixed to the base 4 and a columnar support portion 34b projecting upward from the end of the base 34a. The side surface of the support portion 34b is formed in a planar shape along the Z-axis direction.

[0029] A pair of Z-axis guide rails 36 are provided on the side of the support portion 34b along the Z-axis direction. A flat Z-axis moving plate 38 is mounted on the pair of Z-axis guide rails 36 so as to be slidable along the Z-axis guide rails 36.

[0030] A nut (not shown) is provided on the back side of the Z-axis moving plate 38. A Z-axis ball screw (not shown), which is positioned along the Z-axis direction between a pair of Z-axis guide rails 36, is screwed into this nut. A Z-axis pulse motor 40, which rotates the Z-axis ball screw, is connected to the end of the Z-axis ball screw. A support member 42 is fixed to the front side of the Z-axis moving plate 38. When the Z-axis ball screw is rotated by the Z-axis pulse motor 40, the Z-axis moving plate 38 and the support member 42 move along the Z-axis guide rails 36 in the Z-axis direction.

[0031] Furthermore, the laser processing apparatus 2 is equipped with a laser beam irradiation unit 44 that irradiates a laser beam onto the workpiece 11 (see Figure 2). The laser beam irradiation unit 44 has a laser processing head 46 supported by a support member 42, and a laser beam 48 is irradiated from the laser processing head 46. Laser processing is performed on the workpiece 11 by irradiating the workpiece 11, which is held by the holding table 28, with the laser beam 48.

[0032] An imaging unit 50 is provided adjacent to the laser processing head 46. The imaging unit 50 is equipped with an image sensor such as a CCD (Charged-Coupled Devices) sensor or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor, and captures images of the workpiece 11 (see Figure 2) held by the holding table 28. There are no restrictions on the type of imaging unit 50; for example, a visible light camera or an infrared camera can be used. Based on the image acquired by imaging the workpiece 11 with the imaging unit 50, alignment of the workpiece 11 and the laser beam 48 is performed.

[0033] When the Z-axis moving plate 38 is moved along the Z-axis, the laser processing head 46 and the imaging unit 50 move (rise and fall) along the Z-axis. This adjusts the focusing position of the laser beam 48 in the Z-axis direction and focuses the imaging unit 50.

[0034] Furthermore, the laser processing apparatus 2 is equipped with a display unit (display section, display device) 52 that displays various information related to the laser processing apparatus 2. For example, a touch panel display is used as the display unit 52. In this case, the display unit 52 displays an operation screen for inputting information into the laser processing apparatus 2, and the operator can input information into the laser processing apparatus 2 by touching the display unit 52. In other words, the display unit 52 also functions as an input unit (input section, input device) for inputting various information into the laser processing apparatus 2 and is used as a user interface. However, the input unit may be an input device such as a mouse or keyboard that is provided separately and independently from the display unit 52.

[0035] Furthermore, the laser processing apparatus 2 includes a control unit (control unit, control device) 54 that controls the laser processing apparatus 2. The control unit 54 is connected to each component that makes up the laser processing apparatus 2 (moving unit 6, holding table 28, clamp 30, laser beam irradiation unit 44, imaging unit 50, display unit 52, etc.). The control unit 54 operates the laser processing apparatus 2 by generating and outputting control signals that control the operation of the components of the laser processing apparatus 2.

[0036] For example, the control unit 54 is comprised of a computer. Specifically, the control unit 54 includes a calculation unit that performs various calculations necessary for the operation of the laser processing device 2, and a storage unit that stores various information (data, programs, etc.) used for the operation of the laser processing device 2. The calculation unit includes a processor such as a CPU (Central Processing Unit). The storage unit includes memory such as ROM (Read Only Memory) and RAM (Random Access Memory).

[0037] Figure 3 is a partial cross-sectional side view of the laser processing apparatus 2. The laser beam irradiation unit 44 includes a laser oscillator 60 such as a YAG laser, YVO4 laser, or YLF laser, and an optical system 62 that guides the laser beam 48 emitted from the laser oscillator 60 to the workpiece 11 held by the holding table 28. The optical system 62 is composed of multiple optical components and controls the direction of travel, shape, and focusing position of the laser beam 48 irradiated onto the workpiece 11.

[0038] Specifically, the optical system 62 includes an output adjustment unit 64 that adjusts the output of the laser beam 48 emitted from the laser oscillator 60, and a light condenser (optical component) 66 that focuses the laser beam 48 emitted from the laser oscillator 60. For example, an attenuator is used as the output adjustment unit 64, and a focusing lens such as a convex lens is used as the light condenser 66.

[0039] Furthermore, the optical system 62 includes one or more optical components 68 that guide the laser beam 48 from the laser oscillator 60 to the condenser 66. The optical components 68 correspond to lenses that shape or focus the laser beam 48, mirrors that reflect the laser beam 48, etc. Figure 3 shows an example where the optical component 68 is a mirror. The laser beam 48 emitted from the laser oscillator 60 is incident on the condenser 66 via the output adjustment unit 64 and the optical components 68.

[0040] However, there are no restrictions on the types of optical components 68. Examples of optical components 68 include lenses, mirrors, polarizing beam splitters (PBS), diffractive optical elements (DOEs), and LCOS-SLMs (Liquid Crystal On Silicon - Spatial Light Modulators). Furthermore, the optical system 62 may be composed of two or more different types of optical components 68.

[0041] Furthermore, the laser beam irradiation unit 44 includes a housing section 70 for housing the components of the optical system 62 (output adjustment unit 64, light condenser 66, optical components 68, etc.). For example, the housing section 70 includes a rectangular parallelepiped container (box) 72 and cylindrical light-shielding tubes 74 and 76. One end of the light-shielding tube 74 is connected to the laser oscillator 60, and the other end of the light-shielding tube 74 is connected to the side wall of the container 72. Also, one end of the light-shielding tube 76 is connected to the bottom wall of the container 72, and the other end of the light-shielding tube 76 is covered by a transparent protective cover through which the laser beam 48 passes. Alternatively, instead of installing a protective cover, the other end of the light-shielding tube 76 may be covered with a light condenser 66.

[0042] The container 72 and the light-shielding tubes 74 and 76 are made of a material that shields the laser beam 48, preventing the laser beam 48 from leaking outside the housing 70. The output adjustment unit 64 and optical components 68 are housed in the container 72, and the light-shielding tube 76 houses the light-gathering device 66. However, the light-gathering device 66 may also be housed in the container 72.

[0043] The laser beam 48 emitted from the laser oscillator 60 enters the container 72 via the light-shielding tube 74 and is incident on the output adjustment unit 64. This allows the output of the laser beam 48 to be adjusted by the output adjustment unit 64. The laser beam 48 emitted from the output adjustment unit 64 is then guided to the light-shielding tube 76 by one or more optical components 68. The laser beam 48 is then incident on the light-focusing unit 66, focused at a predetermined position, and irradiated onto the workpiece 11 held by the holding table 28.

[0044] When processing a workpiece 11 with the laser processing device 2, the workpiece 11 is first held by the holding table 28. For example, the workpiece 11 is placed on the holding table 28 such that the front surface 11a is exposed upwards and the back surface 11b (sheet 19 side) faces the holding surface 28a. The frame 17 is also fixed by multiple clamps 30. In this state, when the suction force (negative pressure) of the suction source is applied to the holding surface 28a, the workpiece 11 is held by the holding table 28 via the sheet 19.

[0045] Next, a laser beam 48 is irradiated from the laser beam irradiation unit 44 toward the workpiece 11, and laser processing is performed on the workpiece 11. The irradiation conditions of the laser beam 48 are set according to the content of the laser processing to be performed on the workpiece 11.

[0046] For example, when performing ablation on a workpiece 11, the wavelength of the laser beam 48 is set so that at least a portion of the laser beam 48 is absorbed by the workpiece 11. In other words, a laser beam 48 that is absorbent by the workpiece 11 is used. In addition, other irradiation conditions of the laser beam 48 (average power, repetition frequency, processing feed rate, etc.) are also set appropriately so that the workpiece 11 is subjected to proper ablation. For example, if the workpiece 11 is a single-crystal silicon wafer and ablation is performed on the single-crystal silicon wafer, the irradiation conditions of the laser beam 48 can be set as follows. Wavelength: 355nm Average output: 2W Repeat frequency: 200kHz Machining feed rate: 400 mm / s

[0047] As the laser beam 48 is focused on the surface 11a or inside the workpiece 11, and the holding table 28 is moved along the processing feed direction by the moving unit 6 (Figure 1), the holding table 28 and the laser beam 48 move relative to each other, and the laser beam 48 is scanned along the processing feed direction. As a result, ablation is performed on the workpiece 11, and linear laser-processed grooves are formed on the surface 11a side of the workpiece 11.

[0048] For example, by forming laser-cut grooves along all streets 13 (see Figure 2) from the surface 11a to the back surface 11b of the workpiece 11, the workpiece 11 is divided along the streets 13. Alternatively, the workpiece 11 can be divided along the streets 13 by first forming laser-cut grooves on the surface 11a side of the workpiece 11 along all streets 13 with a depth less than the thickness of the workpiece 11, and then grinding the back surface 11b side of the workpiece 11 with a grinding wheel to expose the laser-cut grooves on the back surface 11b of the workpiece 11. As a result, multiple device chips, each containing a device 15, are manufactured.

[0049] Furthermore, if foreign matter such as particles (dust, etc.) adheres to the components of the optical system 62 (output adjustment unit 64, light concentrator 66, optical components 68, etc.), various problems may occur, such as distortion of the shape of the laser beam 48, shift in the focusing position, and a decrease in output. For this reason, the components of the optical system 62 are housed in a housing section 70 so as to be isolated from the outside. This prevents particles from the atmosphere from adhering to the components of the optical system 62.

[0050] However, components other than those of the optical system 62 are also placed inside the housing section 70. For example, holders for holding the optical components 68 and actuators such as motors for controlling the position or angle of the optical components 68 are housed in the housing section 70 together with the optical components 68. Therefore, even if the inside of the housing section 70 is isolated and sealed, outgassing from the holders and actuators may adhere to the optical components 68, contaminating them. Also, during maintenance of the laser processing apparatus 2, the container 72 is opened to adjust, replace, or clean the components of the optical system 62. At that time, particles may enter and accumulate inside the housing section 70 and adhere to the components of the optical system 62 after maintenance.

[0051] Therefore, in the laser beam irradiation unit 44 of this embodiment, an ionizer 78 for capturing foreign matter such as particles present inside the housing 70 is provided inside the housing 70. This prevents foreign matter present inside the housing 70 from floating and adhering to the components of the optical system 62, making it possible to irradiate the workpiece 11 with the laser beam 48 under appropriate conditions.

[0052] For example, the ionizer 78 includes a discharge electrode (discharge needle), an earth terminal, and a high-voltage power supply. When a high voltage is applied to the discharge electrode, corona discharge occurs between the discharge electrode and the earth terminal. This ionizes the air around the discharge electrode, generating positive and negative ions. For example, a bar-type ionizer 78 is fixed to the upper wall of a container 72, and the ions generated by the ionizer 78 are dispersed inside the container 72.

[0053] The ions generated by the ionizer 78 act on foreign matter such as particles present inside the container 72, causing them to become charged. The charged foreign matter then adheres to the discharge electrode of the ionizer 78 to which voltage is applied. As a result, the foreign matter inside the container 72 is captured and collected by the ionizer 78, preventing it from adhering to the output adjustment unit 64, the light concentrator 66, the optical components 68, etc.

[0054] There are no restrictions on the type, number, or installation location of the ionizer 78. For example, multiple spot-type (nozzle-type) ionizers 78 may be installed inside the container 72. In this case, foreign matter can be captured at multiple points inside the container 72. Also, if the optical system 62 has multiple optical components 68, an ionizer 78 may be installed for each optical component 68. In this case, the multiple ionizers 78 are positioned within a predetermined range from each corresponding optical component 68. This prevents foreign matter from adhering to the multiple optical components 68 by each individual ionizer 78. Furthermore, the ionizers 78 can be installed inside the light-shielding tubes 74 and 76 in addition to inside the container 72. In particular, by providing an ionizer 78 inside the light-shielding tube 76, the adhesion of foreign matter to the light-collecting device 66 is effectively prevented.

[0055] However, when the ionizer 78 is activated, airflow is generated inside the housing 70, making it difficult for foreign matter to adhere to the ionizer 78 as it is carried away by the airflow. For this reason, it is preferable that the ionizer 78 be a windless type that does not use air blowing.

[0056] Figure 4 is a graph showing the relationship between the duration of ion generation (operating time of the ionizer 78) and the amount of ions generated. When ion generation by the ionizer 78 continues, foreign matter gradually accumulates on the discharge electrode of the ionizer 78, and the exposed area of ​​the discharge electrode decreases. As a result, the amount of ions generated by the ionizer 78 decreases. In other words, the more foreign matter is captured by the ionizer 78 and the cleaner the inside of the containment section 70 becomes, the less ions are generated by the ionizer 78. Therefore, there is a correlation between the amount of ions generated by the ionizer 78 and the cleanliness of the containment section 70.

[0057] Therefore, the laser processing apparatus 2 may determine the cleanliness of the inside of the containment section 70 based on the amount of ions generated by the ionizer 78. This makes it possible to monitor the cleanliness of the containment section 70 and perform maintenance on the optical system 62 and the ionizer 78 or replace parts at the appropriate time.

[0058] Specifically, the laser beam irradiation unit 44 is equipped with a detector that acquires information (ion quantity information) corresponding to the amount of ions generated by the ionizer 78. For example, the ionizer 78 is connected to an ammeter 80 that measures the current flowing inside the ionizer 78. The ammeter 80 may also be built into the ionizer 78.

[0059] The ionizer 78 and the ammeter 80 are connected to the control unit 54. The control unit 54 operates the ionizer 78 by outputting a control signal to it, causing the ionizer 78 to generate ions. While the ionizer 78 is operating, the current flowing through it is measured and monitored by the ammeter 80.

[0060] When the ionizer 78 is operated for a certain period of time, charged foreign matter accumulates on the discharge electrode of the ionizer 78, reducing the amount of ions generated (see Figure 4), and changing the current flowing through the ionizer 78. Therefore, the current value measured by the ammeter 80 corresponds to the amount of ions generated by the ionizer 78. The current value measured by the ammeter 80 is then input to the control unit 54 as ion quantity information.

[0061] The control unit 54 includes a determination unit 82 that determines the cleanliness of the inside of the containment unit 70 based on the amount of ions generated by the ionizer 78, and a reference information storage unit 84 that stores information used by the determination unit 82 to determine the cleanliness. The determination unit 82 determines the cleanliness of the containment unit 70 based on ion amount information (current value) input from the ammeter 80 and reference information stored in the reference information storage unit 84.

[0062] For example, the reference information storage unit 84 stores a reference value (threshold) for the ion quantity information measured by the ammeter 80. The determination unit 82 then determines the cleanliness of the containment unit 70 by comparing the ion quantity information input from the ammeter 80 with the reference value stored in the reference information storage unit 84. Specifically, if the current value measured by the ammeter 80 is equal to or greater than the reference value (or exceeds the reference value), the determination unit 82 determines that the cleanliness of the containment unit 70 is normal. On the other hand, if the current value measured by the ammeter 80 is less than or equal to the reference value (or less than or equal to the reference value), the determination unit 82 determines that the cleanliness of the containment unit 70 is abnormal.

[0063] However, there are no restrictions on the method for determining the cleanliness of the containment section 70. For example, the reference information storage unit 84 may store multiple reference values. In this case, the determination unit 82 can determine the cleanliness of the containment section 70 at three or more levels by comparing the ion quantity information input from the ammeter 80 with the multiple reference values.

[0064] Furthermore, the reference information storage unit 84 may store correspondence relationship information (graphs, tables, etc.) that represents the correspondence between the ion quantity information measured by the ammeter 80 and the cleanliness of the containment unit 70. In this case, the determination unit 82 can identify the cleanliness corresponding to the ion quantity information by applying the ion quantity information input from the ammeter 80 to the correspondence relationship information.

[0065] When the determination unit 82 determines the cleanliness of the storage unit 70, the control unit 54 outputs a control signal to the display unit 52 (see Figure 1), causing the result of the determination unit 82 to be displayed on the display unit 52. For example, the display unit 52 displays characters, shapes, symbols, numbers, etc., corresponding to the result of the determination unit 82. In this way, the cleanliness of the storage unit 70 is notified to the operator.

[0066] Furthermore, if multiple ionizers 78 are provided in the housing unit 70, an ammeter 80 is connected to each ionizer 78, and the cleanliness level is determined for each ionizer 78. The display unit 52 then displays the cleanliness level determined by each determination unit 82, along with information indicating the location where the ionizer 78 is installed. This allows the operator to understand the variation in cleanliness levels within the housing unit 70.

[0067] Furthermore, the control unit 54 may display the time progression of the cleanliness of the containment unit 70, as determined by the determination unit 82, on the display unit 52. For example, a graph showing the relationship between the operating time of the ionizer 78 (duration of ion generation) and the cleanliness of the containment unit 70 as determined by the determination unit 82 can be displayed on the display unit 52. This allows the operator to understand the time progression of the cleanliness of the containment unit 70.

[0068] As described above, the laser processing apparatus 2 according to this embodiment includes a housing section 70 that houses the optical system 62 of the laser beam irradiation unit 44, and an ionizer 78 for capturing foreign matter is installed inside the housing section 70. This makes it difficult for foreign matter present inside the housing section 70 to adhere to the components of the optical system 62, and makes it possible to irradiate the workpiece 11 with the laser beam 48 under appropriate conditions.

[0069] Furthermore, the laser processing apparatus 2 according to this embodiment includes a determination unit 82 that determines the cleanliness of the inside of the containment unit 70 based on the amount of ions generated by the ionizer 78. This makes it possible to monitor the cleanliness of the inside of the containment unit 70 and to perform maintenance on the optical system 62 and the ionizer 78, as well as replace parts, at an appropriate time.

[0070] Although the above description explains the case where the ion quantity information is the current value measured by the ammeter 80, there are no restrictions on the type of detector used to acquire the ion quantity information. For example, the laser beam irradiation unit 44 may be equipped with an ion measuring instrument that measures the amount of ions generated by the ionizer 78.

[0071] The ion meter is housed in the housing section 70 so as to be positioned near the ionizer 78. The ion meter may also be built into the ionizer 78. Furthermore, if multiple ionizers 78 are housed in the housing section 70, multiple ion meters may be installed near each of the ionizers 78.

[0072] While the ionizer 78 is operating, the amount of ions generated by the ionizer 78 is measured by an ion meter. The amount of ions measured by the ion meter is input to the control unit 54 as ion quantity information. The determination unit 82 then determines the cleanliness of the containment unit 70 based on the amount of ions measured by the ion meter and the reference information (reference values, etc.) stored in the reference information storage unit 84.

[0073] Furthermore, the laser processing apparatus 2 shown in Figure 1 may be equipped with a notification unit (notification unit, notification device) to alert the operator of any abnormalities. For example, an indicator light (warning light) may be installed on the top of the laser processing apparatus 2 as the notification unit. If the cleanliness of the housing 70, as determined by the determination unit 82, is abnormal, the control unit 54 will notify the operator of the abnormal cleanliness by lighting or flashing the indicator light. The notification unit may also be a speaker that notifies the operator of abnormalities with sound or voice.

[0074] Furthermore, the structures, methods, etc., according to the above embodiments can be modified as appropriate without departing from the scope of the objectives of the present invention. [Explanation of Symbols]

[0075] 11 Workpiece 11a surface 11b Back side 13th Street (planned division line) 15 devices 17 frames 17a aperture 19 seats 2. Laser processing equipment 4 base 6. Mobile Unit (Movement Mechanism) 8. Y-axis movement unit (indexing feed unit) 10 Y-axis guide rail 12 Y-axis moving table 14 Y-axis ball screw 16 Y-axis pulse motor 18 X-axis movement unit (machining feed unit) 20 X-axis guide rail 22 X-axis moving table 24 X-axis ball screw 26 X-axis pulse motor 28. Holding table (chuck table) 28a Holding surface 30 clamps 32 Z-axis movement unit (Z-axis movement mechanism) 34 Support structure 34a base 34b Support part 36 Z-axis guide rails 38 Z-axis movement plate 40 Z-axis pulse motor 42 Support member 44 Laser beam irradiation unit 46 Laser processing heads 48 Laser beams 50 imaging units 52 Display unit (display section, display device) 54 Control Unit (Control Unit, Control Device) 60 Laser Oscillators 62 Optical system 64 Output Adjustment Unit 66. Light concentrator (optical component) 68 Optical Components 70 Storage Units 72 Container (box) 74,76 Shade tube 78 Ionizer 80 ammeter 82 Judgment section 84 Reference information storage unit

Claims

1. A laser processing device for processing a workpiece, A holding table for holding the workpiece, The system comprises a laser beam irradiation unit that irradiates a laser beam onto the workpiece held by the holding table, The laser beam irradiation unit is Laser oscillator and, A focuser that focuses the laser beam emitted from the laser oscillator, An optical component that guides the laser beam from the laser oscillator to the light condenser, A housing section for housing the optical component, A laser processing apparatus characterized by having an ionizer provided inside the housing section for capturing foreign matter present inside the housing section.

2. The laser processing apparatus according to claim 1, characterized in that the ionizer is of the windless type.

3. The laser processing apparatus according to claim 1 or 2, further comprising a determination unit that determines the cleanliness of the inside of the containment based on the amount of ions generated by the ionizer.

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