KR20150057997A - Detecting apparatus - Google Patents

Abstract

Provided is a detecting apparatus that can accurately verify the machining state of a machined workpiece. The apparatus includes a workpiece holding means comprising a holding surface for holding a workpiece, an interference type imaging device for outputting image signals picked up by imaging the workpiece held on the holding surface of the holding means, an X-axis moving means for moving the workpiece holding means and the interference type imaging device relatively in the X-axis direction, a Y-axis moving means for moving the workpiece holding means and the interference type imaging device relatively to the Y-axis direction perpendicular to the X-axis direction, a Z-axis moving means for moving the workpiece holding means and the interference type imaging device relatively to the Z-axis direction perpendicular to the X-axis direction and the Y-axis direction, a control means for generating image information on the basis of the image signal output from the interference type imaging device, and an output means for outputting the image information generated by the control means. The control means operates the interference type imaging device by providing the location of the interference type imaging device at a predetermined position in the Z-axis direction, generates the information of XY 2 dimension image by moving the workpiece holding means and the interference type imaging device relatively to the X-axis direction or the Y-axis direction, and outputs the image information to the output means.

Description

DETECTING APPARATUS

The present invention relates to a detecting device for detecting a machining state of a machining groove such as a laser machining groove or a cutting groove machined on a workpiece such as a wafer or an uneven state of a grinding wheel on a machined surface to be ground.

In the semiconductor device manufacturing process, a plurality of areas are partitioned by a line to be divided which is arranged in a lattice pattern on the surface of a wafer having a substantially disk shape, and devices such as IC and LSI are formed in the partitioned area. Then, the back surface of the wafer is ground to form a predetermined thickness, and then cut along the line to be divided, thereby dividing the region where the device is formed to manufacture individual devices.

The grinding apparatus for grinding the back side of the wafer includes a chuck table for holding the wafer, grinding means having a grinding wheel for grinding the wafer held on the chuck table, thickness measuring means for measuring the thickness of the wafer, and the like (See, for example, Patent Document 1).

The above-described division of the wafer along the line to be divided is performed by a cutting apparatus or a laser processing apparatus.

The cutting apparatus includes a chuck table for holding a wafer, cutting means having a cutting blade for cutting the wafer held on the chuck table, imaging means for detecting a line to be divided formed on the wafer held on the chuck table, and the like (See, for example, Patent Document 2).

The laser processing apparatus includes a chuck table for holding a wafer, laser beam irradiating means for irradiating the wafer held by the chuck table with a laser beam, imaging means for detecting a line to be divided formed on the wafer held on the chuck table And the like (see, for example, Patent Document 3).

In the cutting apparatus and the laser processing apparatus, the cutting grooves and the laser machining grooves are imaged by the image pickup means to detect the state of the cutting grooves and the state of the laser machining grooves to adjust the machining conditions (see, for example, Patent Document 4 Reference).

Patent Document 1: JP-A-2002-319559 Patent Document 2: JP-A-7-45556 Patent Document 3: JP-A-2008-12566 Patent Document 4: JP-A-5-326700

Thus, the image picked up by the image pickup means is a two-dimensional image on the surface, and a two-dimensional image of a predetermined depth from the surface, a three-dimensional image of the depth or cross- Dimensional image such as a three-dimensional image can not be detected, so that there is a problem that the processing state can not be verified in detail.

Further, in the grinding apparatus, there is a problem that the uneven state of the grinding streak can not be verified.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is a main object of the present invention to provide a detecting device which can accurately verify a machining state in which a machining process is performed.

According to an aspect of the present invention, there is provided an image processing apparatus comprising: a workpiece holding means having a holding surface for holding a workpiece; a workpiece holding means for holding a workpiece held on the holding surface of the workpiece holding means; An X-axis moving means for relatively moving the workpiece holding means and the interference type imaging mechanism in the X-axis direction, and an X-axis moving means for relatively moving the workpiece holding means and the interference type imaging mechanism in X A Y-axis moving means for moving the workpiece holding means and the interference type imaging mechanism in a Y-axis direction orthogonal to the X-axis direction and the Y-axis direction; Control means for generating image information based on the image signal outputted from the interference type image pickup device; An output means for outputting the information,

Wherein the control means is configured to position and operate the imaging position of the interference type imaging mechanism at a predetermined position in the Z axis direction and to move the workpiece holding means and the interference type imaging mechanism relatively in the X axis direction or the Y axis direction And generates image information of the XY two-dimensional image, and outputs the image information to the output means.

The control means moves the workpiece holding means and the interference type imaging mechanism relatively in the Z axis direction in the specified area of the XY two-dimensional image to generate image information of the XYZ three-dimensional image, And outputs the information to the output means.

The interference type imaging mechanism may further include imaging element means in which a plurality of pixels are arranged in the X-axis direction and the Y-axis direction, a condenser facing the holding surface of the workpiece holding means, and a light- And an interference light generating means for generating return light and interference light reflected from the workpiece held on the holding surface of the workpiece holding means,

Wherein the control means stores an XY coordinate storage area for storing coordinates in the X axis direction and a Y axis direction of the pixel of the imaging element means that captures strong light generated by the interference light generation unit and an XY coordinate for each Z axis position storage And generates image information of the XY two-dimensional image based on the XY coordinates stored in the memory, and generates image information of the XYZ three-dimensional image based on the XYZ coordinates.

A machining state detecting apparatus according to the present invention includes a workpiece holding means having a holding surface for holding a workpiece, a workpiece holding means for holding a workpiece held on the holding surface of the workpiece holding means, Axis moving mechanism moves the workpiece holding means and the interference type imaging mechanism relatively in the Y axis direction orthogonal to the X axis direction by moving the workpiece holding mechanism and the interference type imaging mechanism relatively in the X axis direction, A Z axis moving means for moving the workpiece holding means and the interference type imaging mechanism relatively in the X axis direction and the Z axis direction orthogonal to the Y axis direction; A control means for generating image information and an output means for outputting image information generated by the control means, And moves the workpiece holding means and the interference type imaging mechanism relatively in the X axis direction or the Y axis direction to generate image information of the XY two-dimensional image , The image information is outputted to the output means. Therefore, the light-converging point (imaging position) of the interference type imaging mechanism is positioned to the depth at which the processing state is to be detected, and the two- .

1 is a perspective view of a laser processing machine as a processing machine equipped with a detecting device constructed according to the present invention.
Fig. 2 is a perspective view in which the constituent members of the interference type imaging mechanism constituting the detection device equipped in the laser processing machine shown in Fig. 1 are exploded. Fig.
3 is a cross-sectional view of a main portion of the interference type imaging mechanism shown in Fig.
FIG. 4 is an explanatory diagram of a light condenser and an interference light generating means constituting the interference type imaging mechanism shown in FIG. 3;
Fig. 5 is a block diagram of processing means provided in the detection apparatus shown in Fig. 1. Fig.
6 is a control map in which the relationship between the voltage applied to the actuator made of the piezo motor and the axial displacement of the piezo motor is set.
7 is a perspective view of a semiconductor wafer as a workpiece mounted on the surface of a dicing tape mounted on an annular frame.
8 is an explanatory diagram of a laser machining groove forming step by the laser machining apparatus shown in Fig.
Fig. 9 is an explanatory diagram of a laser machining groove confirmation step by the detection device shown in Fig. 1;
10 is an explanatory diagram of a detailed laser machining groove confirmation step by the detection apparatus shown in Fig.

Best Mode for Carrying Out the Invention Hereinafter, a preferred embodiment of a detection apparatus constructed in accordance with the present invention will be described in more detail with reference to the accompanying drawings.

Fig. 1 shows a perspective view of a laser processing machine as a processing machine equipped with a detection device constructed according to the present invention. A laser machining apparatus 1 shown in Fig. 1 is provided with a stationary base 2 and a stationary base 2 which is movably disposed in a processing transfer direction (X-axis direction) indicated by an arrow X in the stationary base 2, A workpiece holding mechanism 3 and a laser beam irradiating unit 4 as laser beam irradiating means which are processing means disposed on the stationary base 2. [

The workpiece holding mechanism 3 includes a pair of guide rails 31 and 31 arranged in parallel along the X axis direction indicated by an arrow X on the stop base 2 and a pair of guide rails 31 and 31 And a second sliding block 32 disposed on the first sliding block 32 so as to be movable in the Y-axis direction orthogonal to the X-axis direction on the first sliding block 32. The first and second sliding blocks 32, A cover table 35 supported on the second sliding block 33 by a cylindrical member 34 and a chuck table 36 as a workpiece holding means. The chuck table 36 is provided with a chucking chuck 361 made of a porous material. The chuck table 36 is provided with a suction chuck 361 on the holding surface which is the upper surface of the chucking chuck 361, Respectively. The chuck table 36 thus configured is rotated by a pulse motor (not shown) disposed in the cylindrical member 34. [ The chuck table 36 is provided with a clamp 362 for fixing an annular frame for supporting a workpiece such as a semiconductor wafer through a protective tape.

The first sliding block 32 is provided with a pair of to-be-guided grooves 321 and 321 on its bottom surface for fitting with the pair of guide rails 31 and 31, A pair of guide rails 322 and 322 are formed. The first sliding block 32 thus configured moves in the X-axis direction along the pair of guide rails 31, 31 by engaging the guided grooves 321, 321 with the pair of guide rails 31, Lt; / RTI > The workpiece holding mechanism 3 in the illustrated embodiment includes an X axis moving means 37 for moving the first sliding block 32 along the pair of guide rails 31 and 31 in the X axis direction Respectively. The X-axis moving means 37 includes a male screw rod 371 disposed in parallel between the pair of guide rails 31 and 31 and a pulse motor 372 for rotationally driving the male screw rod 371 And a driving source. One end of the male screw rod 371 is rotatably supported by a bearing block 373 fixed to the stationary base 2 and the other end of the male screw rod 371 is electrically connected to the output shaft of the pulse motor 372 have. The male screw rod 371 is screwed to a female screw hole formed in a female screw block (not shown) provided on a central lower surface of the first sliding block 32 so as to protrude therefrom. Therefore, the first slide block 32 is moved in the X-axis direction along the guide rails 31, 31 by driving the male screw rod 371 in the normal rotation and the reverse rotation by the pulse motor 372.

The laser machining apparatus 1 in the illustrated embodiment is provided with X-axis direction position detection means 374 for detecting the X-axis direction position of the chuck table 36. [ The X-axis direction position detecting means 374 includes a linear scale 374a disposed along the guide rail 31 and a linear scale 374a disposed in the first sliding block 32 and coupled with the first sliding block 32, And a read head 374b which moves along the scanning direction. In the illustrated embodiment, the read head 374b of the X-axis direction position detecting means 374 sends a pulse signal of one pulse every 1 占 퐉 to the control means described later. The control means, which will be described later, detects the position of the chuck table 36 in the X-axis direction by counting the inputted pulse signals. When the pulse motor 372 is used as the driving source of the X-axis moving means 37, the driving pulses of the control means, which will be described later, for outputting the driving signal to the pulse motor 372 are counted, The X-axis direction position of the wafer W can be detected. When a servo motor is used as the driving source of the X-axis moving means 37, a pulse signal outputted by a rotary encoder for detecting the number of rotations of the servo motor is sent to a control means described later, The position of the chuck table 36 in the X-axis direction can be detected.

The second sliding block 33 is provided with a pair of to-be-guided grooves 331 and 331 on its bottom surface for engaging with a pair of guide rails 322 and 322 provided on the upper surface of the first sliding block 32 And is movable in the Y-axis direction indicated by an arrow Y perpendicular to the X-axis direction by engaging the guided grooves 331 and 331 with the pair of guide rails 322 and 322. The workpiece holding mechanism 3 in the illustrated embodiment moves the second sliding block 33 along the pair of guide rails 322 and 322 provided in the first sliding block 32 in the Y axis direction And a Y-axis moving means 38 for moving the Y-axis. The Y axis moving means 38 includes a male screw rod 381 disposed parallel to the pair of guide rails 322 and 322 and a pulse motor 382 for rotationally driving the male screw rod 381 And a driving source. One end of the male screw rod 381 is rotatably supported by a bearing block 383 fixed to the upper surface of the first sliding block 32. The other end of the male screw rod 381 is electrically connected to the output shaft of the pulse motor 382 . The male screw rod 381 is screwed to a female screw hole formed in a female screw block (not shown) provided on a central lower surface of the second sliding block 33. Therefore, the second slide block 33 is moved in the Y-axis direction along the guide rails 322 and 322 by driving the male screw rod 381 in the forward rotation and the reverse rotation by the pulse motor 382.

The laser machining apparatus 1 in the illustrated embodiment is provided with Y-axis direction position detection means 384 for detecting the Y-axis direction position of the second sliding block 33. [ The Y-axis direction position detecting means 384 includes a linear scale 384a disposed along the guide rail 322 and a linear scale 384a disposed on the second sliding block 33 together with the second sliding block 33. [ (Not shown). In the illustrated embodiment, the read head 384b of the Y-axis direction position detecting means 384 sends a pulse signal of one pulse every 1 占 퐉 to the control means described later. The control means, which will be described later, detects the position of the chuck table 36 in the Y-axis direction by counting the inputted pulse signals. When the pulse motor 382 is used as the driving source of the Y-axis moving means 38, the chuck table 36 is rotated by counting the driving pulses of the control means described later that outputs the driving signal to the pulse motor 382, Axis position in the Y-axis direction. When a servo motor is used as the driving source of the Y-axis moving means 38, a pulse signal outputted by a rotary encoder for detecting the number of rotations of the servo motor is sent to a control means described later, The position of the chuck table 36 in the Y-axis direction can be detected.

The laser beam irradiation unit 4 includes a support member 41 disposed on the stationary base 2, a gas casing 42 supported substantially by the support member 41 and extending substantially horizontally, A laser beam irradiating means 5 arranged on the base casing 42 and an imaging means 6 for detecting a machining region to be laser machined. The laser beam irradiating means 5 includes a pulse laser beam emitting means disposed in the base casing 42 and having a pulse laser beam oscillator and a repetition frequency setting means (not shown), and a pulsed laser beam emitting means And a machining head 51 for irradiating the workpiece held on the chuck table 36 with light.

The image pickup means 6 is arranged on the gas casing 42 at a predetermined distance on the same line in the X-axis direction from the machining head 51. The imaging means 6 includes, in addition to a normal imaging device (CCD) for imaging by visible light, an infrared illumination means for irradiating the workpiece with infrared rays, an optical system for capturing the infrared rays emitted by the infrared illumination means, And an image pickup element (infrared CCD) for outputting an electric signal corresponding to the infrared ray captured by the optical system, and sends the captured image signal to a control means (not shown).

In the laser machining apparatus 1 in the illustrated embodiment, a detection device 7 for detecting a machining state in which a workpiece held in the chuck table 36 is machined is disposed. The detection device 7 detects the X axis direction, the Y axis direction orthogonal to the X axis direction, the X axis direction, and the Z axis direction orthogonal to the Y axis direction arranged in the gas casing 42, (70) for picking up the workpiece held by the workpiece (36) and outputting the picked up image signal. The interference type imaging mechanism 70 is supported so as to be movable in the Z-axis direction by the first Z-axis moving means 8 disposed in the base casing 42. [ The interference type imaging mechanism 70 and the first Z-axis moving means 8 will be described with reference to Figs. 2 to 4. Fig.

The interference type imaging mechanism 70 shown in Figs. 2 to 4 is a so-called mirau type interference type imaging mechanism and includes an instrument housing 71 and the mechanism housing 71, A condenser 73 disposed at the lower portion of the mechanism housing 71 and opposed to the holding surface (upper surface) of the chuck table 36, and a condenser 73 disposed above the condenser 73 And a light irradiation means (74) for irradiating light to the workpiece held on the holding surface of the chuck table (36). The imaging element unit 72 has a plurality of pixels arranged in the X-axis direction and the Y-axis direction, and outputs the picked-up image signal to the control means described later.

The condenser 73 constituting the interference type imaging mechanism 70 is constituted of a condenser case 731 and an objective lens 732 disposed in the condenser case 731. [ The objective lens 732 condenses the light from the light irradiating means 74, which will be described later, to the light-converging point P (imaging position) as shown in Fig. Further, in the illustrated embodiment, the condensing spot of the condensing point P is set to? 100 占 퐉. The condenser case 731 of the condenser 73 constructed as described above is provided with interference light generating means 75 for generating the return light and the interference light reflected from the workpiece held on the holding surface of the chuck table 36 . The interference light generating means 75 includes a glass plate 751 disposed on the chuck table 36 side from the objective lens 732 and a first lens 752 disposed on the chuck table 36 side from the glass plate 751. [ And a beam splitter 752. The glass plate 751 has a fine mirror 751a having a diameter of, for example,? 0.5 mm at the center. The first beam splitter 752 transmits light condensed by the objective lens 732 emitted from the light irradiation means 74 and irradiates the workpiece held on the holding surface of the chuck table 36, And reflects the light toward the mirror 751a of the reflecting mirror 751. The condenser 73 and the interference light generating means 75 constructed as described above are arranged such that the return light reflected from the light-converging point P (imaging position) and the light reflected from the first beam splitter 752 are reflected by the glass plate 751 And generates an interference light having a high light intensity when it interferes, and guides the interference light toward the imaging element unit 72.

3, the condenser case 731 of the condenser 73 in which the objective lens 732 and the interference light generating means 75 are disposed is mounted on the bottom wall 711 of the mechanism housing 71, (Upper and lower directions in Fig. 3) perpendicular to the holding surface (upper surface) of the chuck table 36 through the upper surface 711a. 3, the condenser case 731 is moved in the vertical direction between the bottom wall 711 of the mechanism housing 71 and the flange portion 731a provided at the upper end of the condenser case 731 in the illustrated embodiment An actuator 76 functioning as a second Z-axis moving means is disposed. In the illustrated embodiment, the actuator 76 is composed of a piezoelectric motor constituted by piezoelectric elements extending in the axial direction corresponding to a voltage value to be applied. Therefore, the actuator 76 composed of the piezo motor is controlled by the control means described later so that the condenser case 731 is moved in the vertical direction (the vertical direction on the holding surface of the chuck table 36 In direction]. The actuator 76 may be a voice coil motor having a high responsiveness such as a piezo motor.

The light irradiating means 74 includes a light source 741 made of LED arranged on a projecting portion 712 on the side of the mechanism housing 71 and a light source 741 in the mechanism housing 71, 73 for guiding the light from the light source 741 to the condenser 73 and guiding the light reflected from the workpiece held on the holding surface of the chuck table 36 to the imaging element means 72, And a beam splitter 742.

Next, the first Z-axis moving means 8 will be described with reference to Fig.

The first Z-axis moving means 8 moves the mechanism housing 71 of the interference type image pickup device 70 in the Z-axis direction indicated by the arrow Z (the direction perpendicular to the holding surface of the chuck table 36) And an operating means 82 for moving the mechanism housing 71 supported by the support case 81 in the Z-axis direction indicated by the arrow Z. The support case 81 is composed of an upper wall 811 and a bottom wall 812, both side walls 813 and 814 and a rear wall (not shown), and both side walls 813 and 814 protrude forward Thereby constituting the rails 813a and 813b. The actuating means 82 includes an upper wall 811 and a male screw rod 821 rotatably pivotally supported on the bottom wall 812 by being disposed between both side walls 813 and 814 of the support case 81, And a driving source such as a pulse motor 822 which is disposed on the upper wall 811 and is electrically connected to the male screw rod 821. The female screw hole 713a formed in the female screw block 713 disposed on the rear wall of the mechanism housing 71 is screwed to the male screw rod 821 of the operating means 82 thus configured. The mechanism housing 71 on which the female screw block 713 is mounted is moved in the Z-axis direction along the guide rails 813a and 813b by rotating the male screw rod 821 in the normal direction and the reverse direction by the pulse motor 822 .

The detection device 7 in the illustrated embodiment is provided with Z-axis direction position detection means (not shown) for detecting the Z-axis direction position of the interference type imaging mechanism 70 moved by the first Z- (80). The Z-axis direction position detecting means 80 includes a linear scale 80a disposed on the guide rail 813a and a mechanism 80b attached to the mechanism housing 71 of the interference type imaging mechanism 70, And a read head 80b which moves together with the linear scale 80a. In the illustrated embodiment, the read head 80b of the Z-axis direction position detecting means 80 configured as described above sends a pulse signal of one pulse every 1 占 퐉 to the control means described later.

The detecting device 7 in the illustrated embodiment includes control means 9 (see FIG. 5) for generating image information based on the image signal outputted from the image pickup device means 72 of the interference type image pickup device 70 ). The control means 9 also controls the respective constituent means of the laser machining apparatus 1 in addition to the constituent means of the machining state detecting device 7. The control means 9 is constituted by a computer and includes a central processing unit (CPU) 91 for performing arithmetic processing according to a control program, a read only memory (ROM) 92 for storing a control program and the like, A random access memory (RAM) 93 for storing and reading data, and an input interface 94 and an output interface 95. The input interface 94 of the control means 9 is connected to the input interface 94 of the X-axis direction position detection means 374, the Y-axis direction position detection means 384, the image pickup means 6, A detection signal from the element means 72 and the read head 80b of the Z axis direction position detection means 80 for detecting the position of the interference type imaging mechanism 70 in the Z axis direction is input. The pulse motor 372 of the X-axis moving means 37, the pulse motor 382 of the Y-axis moving means 38, and the laser beam irradiating means (not shown) from the output interface 95 of the control means 9 A pulse motor 822 of the first Z-axis moving means 8, an actuator 76 composed of a piezo motor serving as a second Z-axis moving means, a light source 741 of the light irradiating means 74, And outputs a control signal to output means 90 such as a display means or a printer. 6, which sets the relationship between the voltage applied to the actuator 76 made up of the piezo motor and the axial displacement of the piezo motor, the random access memory (RAM) The storage area 93a and the coordinates in the X axis direction and the Y axis direction of the pixels of the imaging element unit 72 that capture the strong light generated by the interference light generation unit 75 of the interference type imaging mechanism 70 are stored XY coordinate storage area 93b for each position in the Z axis direction of the pixel of the imaging element unit 72 that captures strong light generated by the interference light generation unit 75 of the interference type imaging mechanism 70, An XYZ coordinate storage area 93c for storing an XYZ coordinate storage area 93c, and other storage areas.

The laser machining apparatus 1 in the illustrated embodiment is configured as described above, and its operation will be described below.

7 is a perspective view showing a state in which the semiconductor wafer 10 as the workpiece to be processed by the laser machining apparatus 1 is mounted on the surface of the dicing tape T mounted on the annular frame F . The semiconductor wafer 10 shown in Fig. 7 is made of a silicon wafer, and a plurality of lines 101 to be divided are formed in a lattice pattern on the surface 10a. Devices 102 such as ICs and LSIs are formed in a plurality of regions.

The laser beam is irradiated along the line 101 to be divided of the semiconductor wafer 10 and the laser beam is irradiated inside the semiconductor wafer 10 along the line 101 to be divided using the above- An embodiment of laser processing for forming a groove will be described.

A dicing tape T to which a semiconductor wafer 10 is adhered is placed on the chuck table 36 of the laser machining apparatus 1 shown in Fig. The semiconductor wafer 10 is sucked and retained via the holding member T. Therefore, the surface 10a of the semiconductor wafer 10 held on the chuck table 36 through the dicing tape T becomes the upper side. The annular frame F on which the dicing tape T is mounted is fixed by a clamp 362 disposed on the chuck table 36. [ The chuck table 36 with the semiconductor wafer 10 sucked and held in this way is positioned directly below the imaging means 6 by the X-axis moving means 37. [

When the chuck table 36 is positioned directly below the imaging unit 6 as described above, the imaging area of the semiconductor wafer 10 to be laser-machined is set by the imaging unit 6 and the control unit 9, And performs an alignment operation to be detected. That is, the image pickup means 6 and the control means 9, not shown, are provided on the machining head 51 of the laser beam irradiation means 5 and the line to be divided 101 formed in the predetermined direction of the semiconductor wafer 10 And performs alignment processing by performing image processing such as pattern matching for alignment. Alignment is similarly performed for the line to be divided 101 formed in the semiconductor wafer 10 in a direction orthogonal to the predetermined direction.

8 (a), the control means 9 moves the chuck table 36 so that one end of the predetermined dividing line 101 (Fig. 8 (a)), which has been determined in advance, Is positioned directly under the processing head 51 of the laser beam irradiating means 5. The laser beam irradiating means 5 is a laser beam irradiating means. Then, the light-converging point P of the pulsed laser beam irradiated from the processing head 51 is aligned with the surface 10a (upper surface) of the semiconductor wafer 10. Next, the control means 9 operates the X-axis moving means 37 while irradiating the semiconductor wafer 10 with the pulsed laser beam of the wavelength having absorbency from the machining head 51 of the laser beam irradiating means 5 The chuck table 36 is moved at a predetermined feed rate in the direction indicated by the arrow X1 in Fig. 8A. When the other end of the line to be divided 101 (the right end in Fig. 8B) reaches the position immediately below the processing head 51, the irradiation of the pulsed laser beam by the laser beam irradiation means 5 is performed And the movement of the chuck table 36 is stopped. As a result, as shown in Figs. 8B and 8C, laser machining grooves 110 are formed in the semiconductor wafer 10 along the line to be divided 101 (laser machining groove forming step ).

The laser machining groove forming step is performed under the following processing conditions, for example.

Wavelength: 355 nm

Repetition frequency: 50 ㎑

Average power: 5 W

Focusing spot: φ10 μm

Feeding speed: 200 mm / sec

Next, a laser machining groove confirmation step for confirming the state of the laser machining groove 110 formed by performing the above-described laser machining groove forming step is performed.

The laser machining groove confirmation step is a step of operating the X-axis moving means 37 to move the chuck table 36 holding the semiconductor wafer 10 subjected to the laser machining groove forming process to the condenser of the interference type imaging mechanism 70 And the laser machining groove 110 formed in the semiconductor wafer 10 is positioned just below the condenser 73. [ Next, the interference type imaging mechanism 70 is lowered from the predetermined standby position by operating the first Z-axis moving means 8, and the actuator 76 made of the piezo motor as the second Z- And the actuator 76 made of a piezo motor is stretched by 60 占 퐉 as shown in Fig. In this state, the light-converging point P (see Fig. 4) of the light irradiated from the light-condenser 73 of the interference type image pickup device 70 is reflected by the surface 10a of the semiconductor wafer 10 held on the chuck table 36 Top surface).

Next, the control means 9 sets the voltage to be applied to the actuator 76 constituted by the piezo-electric motor constituting the interference type image pickup device 70 from 60 V to 20 V down to 40 V. As a result, as shown in Fig. 6, the actuator 76 made of a piezo motor is shortened by 1 占 퐉 each time the voltage is lowered by 1 V, so that the condenser 73 is lowered by 20 占 퐉 in the Z-axis direction. Accordingly, the light-converging point P (imaging position) of the condenser 73 constituting the interference type imaging mechanism 70 is lowered by 20 占 퐉 in the Z-axis direction from the surface 10a (upper surface) of the semiconductor wafer 10 And is positioned at one position. Next, the control means 9 operates the imaging element means 72 constituting the interference type imaging mechanism 70, the light source 741 of the light irradiation means 74, and operates the X-axis moving means 37 . Then, an image received by the imaging element unit 72 is sent to the control unit 9. [ The control means 9 blows an image signal sent from the imaging element means 72 every 100 mu m on the basis of the detection signal from the X axis direction position detection means 374, Coordinates of X-axis direction positions (X1, X2, X3, ...) of the pixels that have received the interference light having the high light intensity described above are obtained and the Y coordinate of the XY coordinate storage area ( 93b. Next, the control means 9 determines whether the interference light having a high light intensity (X1, X2, X3, ...) for each position in the X axis direction stored in the random access memory (RAM) Dimensional image of the laser machining groove 110 formed on the semiconductor wafer 10 as shown in Fig. 9 (b) based on the coordinates, stores the two-dimensional image in the random access memory (RAM) 93, 90, and displayed on a display means such as a monitor or printed out by a printer. Dimensional image of the laser machining groove 110 is displayed on a display means such as a monitor as the output means 90 or printed out by the printer so that the size of the laser machining groove 110 It is possible to efficiently acquire a two-dimensional image at a predetermined depth position (a position at a depth of 20 占 퐉 in the illustrated embodiment), and verify the processing state.

As a result of verifying the machining state by the two-dimensional image at the predetermined depth position of the laser machining groove 110 for which the machining state is to be detected as described above, the machining state is verified, and as a result, Verify. Hereinafter, a detailed laser machining groove confirmation process of a portion (for example, the above-described X3 position) of the laser machining groove 110 in the machining state will be described.

First, the control means 9 operates the X-axis moving means 37 to move the chuck table 36 holding the semiconductor wafer 10 to the lower side of the condenser 73 of the interference type imaging mechanism 70 , The X3 position of the laser processing groove 110 formed in the semiconductor wafer 10 is positioned directly below the condenser 73. [ Next, the interference type imaging mechanism 70 is lowered from the predetermined standby position by operating the first Z-axis moving means 8, and the actuator 76 made of the piezo motor as the second Z- And the actuator 76 made of a piezo motor is stretched by 60 占 퐉 as shown in Fig. In this state, the light-converging point P (see Fig. 4) of the light irradiated from the light-condenser 73 of the interference type image pickup device 70 is reflected by the surface 10a of the semiconductor wafer 10 held on the chuck table 36 Top surface).

Next, the control means 9 operates the imaging element means 72 constituting the interference type imaging mechanism 70 and the light source 741 of the light irradiation means 74, and controls the actuator 76 composed of the piezo motor The applied voltage is lowered by 1 V at 60 V. As a result, in the illustrated embodiment, as shown in Fig. 6, since the actuator 76 made of the piezo motor is shortened by 1 占 퐉 each time the voltage is lowered by 1 V, the condenser 73 is moved in the Z- Descend. Thus, every time the condenser 73 is lowered by 1 占 퐉, an image received by the imaging element unit 72 is sent to the control unit 9. [ 10 (a), based on the image signal sent from the imaging element means 72, the control means 9 controls the XY coordinate of the pixel, which has received the above-described interference light having the high light intensity, And stored in the XYZ coordinate storage area 93c of the random access memory (RAM) 93. The XYZ coordinate storage area 93c of the random access memory (RAM) The Z-axis direction positions Z1, Z2, Z3, ... are detected by a detection signal from the read head 80b of the Z-axis direction position detecting means 80 or a signal Voltage signal. Further, since the piezo motor can be operated at a high speed, image information can be acquired in a short time. Therefore, the control means 9 for controlling the voltage applied to the Z-axis direction position detecting means 80 and the actuator 76 composed of the piezo motor is also in the Z-axis direction position for detecting the position in the Z-axis direction of the condenser 73 And functions as a detection means. The control means 9 controls the XY coordinates (X1, Y2, Z3, ...) of the pixel, which receives the interference light having high light intensity at each position in the Z axis direction stored in the random access memory Dimensional image at the X3 position of the laser machining groove 110 formed in the semiconductor wafer 10 and stores it in the random access memory (RAM) 93 as shown in Fig. 10 (b) And outputs it to the output means 90 to be displayed on a display means such as a monitor or printed out by the printer. Thus, by acquiring the three-dimensional image of the portion (particularly, the X3 position in the illustrated embodiment) which is particularly concerned in the verification of the machining state of the laser machining groove 110 in the two-dimensional image, Therefore, appropriate machining conditions can be set by adjusting machining conditions.

Although the present invention has been described based on the embodiments shown above, the present invention is not limited to the embodiments, and various modifications are possible within the scope of the present invention. For example, in the above-described embodiment, the present invention is applied to a laser processing machine. However, the present invention can be applied to a cutting machine to verify the depth and cross-sectional shape of a cutting groove, or to apply to a grinding machine, Can be verified.

In the above-described embodiment, an example in which the mirror-type interference type imaging mechanism is used as the interference type imaging mechanism 70 is described. However, the so-called Michelson type interference type imaging mechanism or the so- Another interference type imaging mechanism such as an imaging mechanism can be used.

2: stop base 3: workpiece holding mechanism
36: chuck table 37: X-axis moving means
38: Y-axis moving means 4: laser beam irradiation unit
5: laser beam irradiation means 51: machining head
6: imaging means 7: detection device
70: Interference type imaging device 72: Imaging device means
73: condenser 732: objective lens
74: light irradiating means 75: interference light generating means
76: actuator 8: first Z-axis moving means
9: control means 10: semiconductor wafer

Claims (3)

A workpiece holding means having a holding surface for holding a workpiece; an interference type imaging mechanism for picking up a workpiece held on the holding surface of the workpiece holding means and outputting an image signal picked up; And an X-axis moving means for relatively moving the interference type imaging mechanism in the X-axis direction; a Y-axis moving means for moving the workpiece holding means and the interference type imaging mechanism in a Y- A Z axis moving means for moving said workpiece holding means and said interference type imaging mechanism relatively in the X axis direction and the Z axis direction orthogonal to the Y axis direction; Control means for generating image information on the basis of the image information, and output means for outputting the image information generated by the control means,
Wherein the control means is configured to position and operate the imaging position of the interference type imaging mechanism at a predetermined position in the Z axis direction and to move the workpiece holding means and the interference type imaging mechanism relatively in the X axis direction or the Y axis direction And generates image information of the XY two-dimensional image, and outputs the image information to the output means. The image processing apparatus according to claim 1, wherein the control means moves the workpiece holding means and the interferometric type imaging mechanism relatively in the Z-axis direction in a specified region of the XY two-dimensional image, Generates image information, and outputs the image information to the output means. 3. The image pickup apparatus according to claim 2, wherein the interference type image pickup mechanism comprises imaging element means in which a plurality of pixels are arranged in the X-axis direction and the Y-axis direction, a condenser facing the holding surface of the workpiece holding means, A light irradiating means for irradiating light to the workpiece held on the holding surface of the workpiece holding means, and an interference light generating means for generating interference light and return light reflected from the workpiece held on the holding surface of the workpiece holding means Means,
Wherein the control means includes an XY coordinate storage area for storing coordinates in the X axis direction and a Y axis direction of the pixel of the imaging element means that captured strong light generated by the interference light generation unit, Dimensional image based on the XY coordinates stored in the memory, and generates image information of the XYZ three-dimensional image based on the XYZ coordinates based on the XYZ coordinate stored in the memory, To generate a detection signal.

Images