JP5788154B2 - Laser beam property management method - Google Patents

Description

  The present invention relates to a method for acquiring information on the cross-sectional intensity distribution of a laser beam used in a laser processing apparatus and managing the characteristics of the laser beam.

  In the semiconductor device manufacturing process, a substantially disk-shaped semiconductor workpiece configured by forming circuits such as IC and LSI in a plurality of regions partitioned by streets (cutting lines) arranged in a lattice pattern on the surface, Individual semiconductor chips are manufactured by cutting along the streets and dividing each circuit. The cutting along the street of the semiconductor work is usually performed by a cutting device called a dicer. In addition, a processing method of cutting by irradiating a laser beam has been attempted (see, for example, Patent Document 1).

JP-A-10-305420

  However, when mass production processing is performed at a factory using laser light, even if the processing conditions are set so that desired processing can be performed by repeating experiments, there may be problems in processing. In addition, devices that have just been diced by laser light may appear to be diced without any particular problems in appearance, but problems may occur when checking device characteristics later. The investigation of the cause required a great deal of labor.

  The present invention has been made in view of these facts, and its main technical problem is that there is a problem in the characteristics of the device after dicing when a problem occurs in processing due to processing by a laser beam. If it occurs, the cause of the problem can be investigated more quickly than before.

The present invention relates to a holding means for holding a workpiece, an oscillator for oscillating a laser beam, a condenser for condensing the laser beam toward the workpiece held by the holding means, an optical path of the laser beam, and a retraction outside the optical path. The present invention relates to a laser beam characteristic management method in a laser processing apparatus having a laser processing means including a movable mirror that can move between positions. When a workpiece is transferred to the holding means, or a problem occurs in the processing of the work. In such a case, the movable mirror is moved from the retracted position onto the optical path of the laser beam, the laser beam is guided to the cross-sectional intensity distribution measuring unit for measuring the cross-sectional intensity distribution of the laser beam, and the laser at the light receiving unit of the cross-sectional intensity distribution measuring unit. Information about the beam receiving process and the cross-sectional intensity distribution of the laser beam acquired by the light receiving unit And a step of transmitting over the Internet to the terminal device, the cross-sectional image information received is analyzed in the terminal device.

  In the present invention, the laser beam is guided to the cross-sectional intensity distribution measuring unit for measuring the cross-sectional intensity distribution of the laser beam, received by the light receiving unit of the cross-sectional intensity distribution measuring unit, and information on the cross-sectional intensity distribution of the laser beam acquired by the light receiving unit is obtained. In order to transmit to the terminal device, the terminal device uses the received information on the cross-sectional strength distribution to investigate the cause when a problem occurs due to processing or a problem occurs in the device characteristics after dicing. Can also be done quickly. Further, even when a problem occurs in which the cause cannot be identified on the laser processing apparatus user side, the terminal apparatus side can quickly solve the problem.

It is a perspective view which shows an example of a laser processing apparatus. It is explanatory drawing which shows an example of the structure of a laser processing means.

(1) Configuration of Laser Processing Device A laser processing device 1 shown in FIG. 1 is a device that processes a workpiece W by irradiating the workpiece W held by a holding unit 2 with laser light from the laser processing unit 3.

  The holding means 2 includes a holding surface 20 that sucks and holds the workpiece W, and a fixing portion 21 that fixes a frame F that supports the workpiece W as illustrated.

  The holding unit 2 is supported by the X-direction feeding unit 4 so as to be movable in the X-axis direction, and supported by the Y-direction feeding unit 5 so as to be movable in the Y-axis direction orthogonal to the X-axis direction. ing.

  The X-direction feed section 4 is disposed on a flat base 53 and includes a ball screw 40 having an axis in the X-axis direction, a pair of guide rails 41 disposed in parallel to the ball screw 40, and the ball screw 40. The motor 42 is connected to one end, an internal nut (not shown) is screwed into the ball screw 40, and a slide portion 43 whose lower portion is in sliding contact with the guide rail 41, and a linear scale 44 arranged in parallel with the ball screw 40. Has been. The X-direction feed section 4 is driven by the motor 42 and, as the ball screw 40 rotates, the slide section 43 slides on the guide rail 41 in the X-axis direction and moves the holding means 2 in the X-axis direction. The position information in the X-axis direction of the holding means 2 is configured to be recognized by a control unit (not shown) as a read value of the linear scale 44.

  The holding means 2 and the X-direction feeding unit 4 are supported by the Y-direction feeding unit 5 so as to be movable in the Y-axis direction. The Y-direction feed section 5 includes a ball screw 50 having an axis in the Y-axis direction, a pair of guide rails 51 arranged in parallel to the ball screw 50, a motor 52 connected to one end of the ball screw 50, and an internal not shown The nut 53 is screwed into the ball screw 50, and the lower part is composed of a base 53 slidably contacting the guide rail 51, and a linear scale 54 disposed in parallel to the ball screw 50. The X-direction feed section 5 is driven by the motor 52 and the base 53 slides on the guide rail 51 in the Y-axis direction as the ball screw 50 rotates, so that the holding means 2 and the X-direction feed section 4 Is moved in the X-axis direction, and the position information of the holding means 2 in the Y-axis direction is recognized as a read value of the linear scale 54 by a control unit (not shown).

  The laser processing means 3 includes a base 30 fixed to the wall 6 and a processing head 31 fixed to the tip of the base 30. The processing head 31 has a function of irradiating a laser beam having an optical axis in the vertical direction.

  As shown in FIG. 2, the laser processing means 3 includes an oscillator 32 that oscillates a laser beam, and a condenser 33 that condenses the laser beam oscillated by the oscillator 32 toward the workpiece W held by the holding means 2. And. The laser beam transmitted from the oscillator 32 is reflected by the reflecting plate 34, travels straight in the vertical direction, is condensed by the condenser 33, and is irradiated onto the workpiece W held by the holding unit 2. A movable mirror 35 that can move between the optical path of the laser beam and a position off the optical path is disposed above the condenser 33.

  As shown in FIG. 2, the laser processing means 3 includes a cross-sectional intensity distribution measuring unit 36 that measures the cross-sectional intensity distribution of the laser beam. The cross-sectional intensity distribution measurement unit 36 includes a light receiving unit 360 that receives the laser beam reflected by the movable mirror 35 in a state where the movable mirror 35 is positioned on the optical path of the laser beam. Further, the cross-sectional intensity distribution measuring unit 36 transmits information on the cross-sectional intensity of the laser beam received by the light receiving unit 360 to any terminal device 38 outside the laser processing apparatus connected via any communication means such as the Internet 37. A transmission unit 361 is provided for transmission. The terminal device 38 is installed at a manufacturer of the laser processing apparatus 1 or the like, for example.

(2) Operation | movement of a laser processing apparatus Operation | movement of the apparatus at the time of carrying out the laser processing of the workpiece | work W using the laser processing apparatus 1 is demonstrated with reference to FIG. As shown in FIG. 1, the workpiece W is configured by forming a device D in an area partitioned by streets S formed on the front surface, and the back surface side is attached to the tape T. A frame F formed in a ring shape is attached to the tape T, and the workpiece W is supported by being integrated with the frame F via the tape T. The workpiece W is sucked and held on the holding surface 20 of the holding means 2 via the tape T, and the frame F is fixed at the fixing portion 21. The workpiece W is not particularly limited. For example, a semiconductor wafer such as a silicon wafer, gallium arsenide, or silicon carbide, an adhesive member such as DAF (Die Attach Film) provided on the back surface of the wafer for chip mounting, or a semiconductor product. Packages, ceramics, glass, sapphire (Al ₂ O ₃ ) -based inorganic material substrates, various electronic components such as liquid crystal display drivers, and various processing materials that require micron-order processing position accuracy.

  When the work W is held by the holding means 2, the holding means 2 is driven in the X direction and the Y direction by the X direction feeding section 4 and the Y direction feeding section 5, and the laser is moved from the machining head 31 along the street S of the work W. A beam is irradiated. By irradiating the laser beam while moving the workpiece W in this way, the laser beam is condensed inside the workpiece W to form a modified layer, or the laser beam is condensed on the surface of the workpiece W to form grooves. Can be formed. During the processing performed in this manner, the movable mirror 35 shown in FIG. 2 is positioned at the retracted position deviated from the optical path. The modified layer is a region where the density, refractive index, mechanical strength and other physical characteristics are different from the surroundings, such as a melt-processed region, a crack region, a dielectric breakdown region, a refractive index. There are changing areas, etc., and there are areas where these are mixed.

(3) Analysis of Cross Section Intensity Distribution of Laser Beam As shown by a two-dot chain line in FIG. 2, when the movable mirror 35 is positioned on the optical path of the laser beam, the cross section intensity distribution measuring unit 36 is moved by the movable mirror 35. The light receiving unit 360 is guided to the transmitting unit 361. Then, the transmission unit 361 transmits image information related to the cross-sectional intensity distribution of the laser beam to the terminal device 38 via the Internet 37. The image information of the cross section of the laser beam may be transmitted to the terminal device 38 each time the cross-sectional intensity distribution measuring unit 36 acquires the image information, or the image information is stored inside the cross-sectional intensity distribution measuring unit 36 In addition, it may be transmitted to the terminal device 38 at a timing when analysis is required. Further, the terminal device 38 can record the received image information in a recording means such as a hard disk (not shown) and read it out as needed.

  For example, when laser processing is performed on a plurality of workpieces in the laser processing apparatus 1, the movable mirror 35 is moved on the optical path at the timing when the workpiece is transferred to the holding means 2 in order not to reduce the processing efficiency. . Then, a cross-sectional image of the laser beam is transmitted from the transmission unit 361 of the cross-sectional intensity distribution measurement unit 36 to the terminal device 38. For example, by displaying the image on the display 380 of the terminal device 38 and analyzing the image, The cross-sectional strength distribution can be grasped. In the terminal device 38, for example, when the color in the image changes according to the intensity of the laser beam, the intensity distribution of the laser beam can be grasped based on the color distribution in the cross-sectional image. .

  When a problem such as device quality occurs in the process after the workpiece W is divided by laser processing, the cause can be clarified by analyzing the cross-sectional image information received by the terminal device 38. .

  If a problem occurs in the processing of the workpiece W, the movable mirror 35 is moved on the optical path immediately after the processing is interrupted, and the cross-sectional image intensity distribution measuring unit 36 acquires the cross-sectional image information of the laser beam and the terminal device. By transmitting to 38, the cause of the malfunction can be immediately investigated. For example, when dust is attached to a component such as the reflector 34 disposed in the optical path of the laser beam, the dust adversely affects the intensity distribution of the laser beam, and the adverse effect appears in the cross-sectional image information. Therefore, by finding the portion where the influence of dust appears in the cross-sectional image information transmitted to the terminal device 38, it is possible to quickly identify the cause of the problem and to solve it.

  As described above, by transmitting the cross-sectional distribution intensity information of the laser beam to the terminal device 38, it is possible to manage the characteristics of the laser beam on the terminal device 38 side. When problems occur in later device characteristics, the cause can be investigated more quickly than in the past. In addition, if there is any problem during processing, the laser processing device user can immediately analyze the intensity distribution information of the laser beam from the processing device manufacturer, so the laser processing device user cannot identify the cause. Even if a problem occurs, it can be resolved quickly.

DESCRIPTION OF SYMBOLS 1: Laser processing apparatus 2: Holding means 20: Holding surface 21: Fixed part 3: Laser processing means 30: Base 31: Processing head 32: Oscillator 33: Light collector 34: Reflecting plate 35: Movable mirror 36: Section strength Distribution measuring unit 360: Light receiving unit 361: Transmitting unit 37: Internet 38: Terminal device 4: X direction feeding unit 40: Ball screw 41: Guide rail 42: Motor 43: Slide unit 44: Linear scale 5: Y direction feeding unit 50: Ball screw 51: Guide rail 52: Motor 53: Base 54: Linear scale

Claims (1)

Holding means for holding the workpiece;
Moveable between an oscillator that oscillates a laser beam, a condenser that focuses the laser beam toward a work held by the holding means, and an optical path of the laser beam and a retracted position off the optical path A laser beam characteristic management method in a laser processing apparatus having a laser processing means including a movable mirror ,
The movable mirror is moved from the retracted position onto the optical path of the laser beam when the workpiece is placed on the holding means or when a problem occurs in the processing of the workpiece, and the laser beam is cross-sectional intensity of the laser beam. A step of leading to a cross-sectional strength distribution measurement unit for measuring the distribution;
Receiving the laser beam at a light receiving unit of the cross-sectional intensity distribution measuring unit;
Transmitting the information on the cross-sectional intensity distribution of the laser beam acquired by the light receiving unit to an arbitrary terminal device outside the laser processing apparatus via the Internet;
A laser beam characteristic management method in which cross-sectional image information received at the terminal device is analyzed.

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