TWI704612B - Wafer processing method and processing device - Google Patents

Abstract

The subject of the present invention is to provide a wafer processing method and a laser processing device that can simultaneously form through holes at a plurality of locations while maintaining the limited maximum repetition frequency of pulsed laser light.

The solution is to provide a wafer processing method and processing device in accordance with the present invention, which is provided with: an elliptical orbit generation step, which is a group of 4 devices, including generation through the devices that are arranged in each device The elliptical trajectory of the four electrode pads at the same position; the laser beam irradiation step is to trace the elliptical trajectory while irradiating the position of the four electrode pads from the back of the wafer Pulse laser light; and the elliptical orbit positioning step, which is to position the elliptical orbit in a way that corresponds to the positions of the four electrode welding to be processed next; while processing and feeding the wafer and the pulse laser relatively The light means implements the laser light irradiation step and the elliptical orbit positioning step in sequence while performing through-hole processing.

Description

Wafer processing method and processing device

The present invention is a processing method and a processing device for forming a laser processing hole on a wafer corresponding to the electrode pads of a device arranged on a processed object such as a semiconductor wafer.

In the semiconductor device manufacturing process, on the surface of a substantially disc-shaped semiconductor wafer, a plurality of areas are divided by planned division lines called trenches arranged in a grid, and the area is formed in the divided areas There are devices such as IC and LSI. Then, the semiconductor wafer is cut along the trench, thereby dividing the area where the device is formed, and manufacturing individual semiconductor wafers.

In order to achieve the miniaturization and high performance of the device, a module structure in which a plurality of devices are stacked and electrode pads (also referred to as bonding pads) provided on the stacked devices are connected are proposed. This module structure is to irradiate the laser light at the place where the electrode pads are provided on the semiconductor wafer to form a through hole (laser processing hole) that reaches the electrode pad. The through hole (laser processing hole) is embedded The structure of a conductive material such as aluminum connected to an electrode pad (for example, refer to Patent Document 1).

[Advanced Technical Literature] [Patent Literature]

[Patent Document 1] JP 2008-062261 A

In order to form the above-mentioned through holes, it is necessary to irradiate the pulsed laser light multiple times at one place. Therefore, in order to improve the production efficiency, it is necessary to increase the repetition frequency of the pulsed laser light. However, once the pulsed laser light is continuously irradiated to a place with a high repetition rate, the wafer will be cracked due to heat build-up, and the quality of the device will be reduced.

In addition, although it differs depending on the device to be manufactured, in order not to cause cracks due to through-hole processing, there are also those that limit the repetition frequency of the pulsed laser light used in the processing (for example, 10 kHz). Therefore, the technical problem to be solved by the present invention is to provide a wafer processing method and a laser processing device that can simultaneously form through holes at multiple locations while maintaining the limited maximum repetition frequency of pulsed laser light. .

In order to solve the above-mentioned main technical problems, according to the present invention, a wafer processing method can be provided, which is a processing method in which a plurality of devices divide a wafer formed on the surface by dividing predetermined lines, and is characterized by: The position information memory step is to memorize the position information of each device formed on the plurality of electrode pads of each device together with the position information of each device on the wafer; the elliptical orbit generation step is to use each other and two adjacent As a group of 4 devices, an elliptical orbit containing a circle passing through 4 electrode pads arranged at the same position of each device is generated; the laser light irradiation step is to draw the elliptical orbit, For the positions of the electrode pads corresponding to the 4, pulse laser light is irradiated by pulse laser light irradiation means; and the elliptical orbit positioning step, which can pass the 4 electrodes corresponding to the next processing The elliptical track is positioned by the position of the bonding pad; while the wafer is relatively processed and fed with the pulsed laser light irradiation means, the laser light irradiation step and the elliptical track positioning step are performed sequentially. For the wafer Perform through-hole processing for forming through-holes corresponding to the electrode pads.

In the laser beam irradiation step, in a state where the elliptical orbit is positioned, it is ideal to perform a plurality of pulsed laser beams to be irradiated to the through holes corresponding to the position coordinates of the four electrode pads.

By executing the laser beam irradiation step for the four devices constituting a group, the first two devices whose laser beam irradiation becomes the first time are partially processed through holes. The through-hole processing is performed, and the laser beam is irradiated for the second time. The other two devices perform through-hole processing on the remaining unprocessed parts, thereby all the electrode pads of the other two devices are processed. The through-hole is processed, By implementing the laser beam irradiation step, the two devices corresponding to all the electrode pads and through-hole processing are cut from the group, and the two devices that have not been through-hole processed partially and adjacent The two unprocessed devices in the processing feed direction are formed into a new group, and the elliptical orbit is positioned for the four devices contained in the new group. The laser light irradiation step and the Oval orbit positioning steps.

In particular, the position is set by sequentially assigning numbers to plural electrode pads arranged in each device, and dividing them into odd-numbered first electrode pad groups and even-numbered second electrode pad groups Information, when the laser light irradiation step for the 4 devices forming a group is performed, the laser light irradiation step is to weld the first electrode pad group and the second electrode of the 4 devices Any one of the unprocessed electrode pad groups in the pad group is irradiated with pulsed laser light while drawing an elliptical orbit, so that the through holes of all the electrode pads corresponding to the two devices are processed. The group cuts the two devices that have processed the through holes for all the electrode pads, and the two devices that perform the through hole processing on only one of the first electrode pad group and the second electrode pad group, and The two unprocessed devices adjacent to the processing feed direction are formed into a new group, and the four devices contained in the new group are positioned on the elliptical orbit. For the first and second electrode pad groups In the unprocessed electrode pad group, the laser light irradiation step and the elliptical orbit positioning step are performed, and it is ideal that the through holes for the two devices are processed in sequence.

In addition, when 4 devices adjacent to 2 devices cannot be grouped on the outer periphery of the wafer, the 4 devices that are less than full The devices are grouped together, and it is ideal to stop the laser beam irradiation in areas where the device is lacking.

In addition, in order to solve the above-mentioned main technical problems, according to the present invention, it is possible to provide a laser processing apparatus, the structure of which includes holding means for holding a wafer on a plane defined by the X axis and the Y axis, A plurality of wafer devices are formed on the surface by dividing a predetermined line; a laser beam irradiation means irradiates the wafer held by the holding means with laser beam to perform processing, and is characterized by: position information Memory means, which together with the position information of the devices on the wafer, memorize the position information of the plural electrode pads formed on each device; the elliptical orbit generation means, which are 4 adjacent to each other and 2 devices As a group, according to the position information of the electrode pad, an elliptical orbit including a circle passing through the four electrode pads arranged at the same position is generated; the elliptical orbit positioning means is the elliptical orbit Positioned at the positions corresponding to the four electrode pads to be processed; and laser light irradiation means, which draws the elliptical orbit while irradiating pulsed laser light at the positions corresponding to the four electrode pads , While processing and feeding the wafer and the pulsed laser beam relatively, actuate the laser beam irradiation means and the elliptical orbit positioning means to form through holes.

The laser light irradiation means includes: an oscillator, which oscillates pulsed laser light at a repetition frequency M that is a multiple of 4; and a concentrator, which concentrates the pulsed laser light oscillated by the oscillator on the The wafer held by the holding means, the elliptical orbit generating means is arranged between the oscillator and the light collector, and shakes the irradiation direction of the laser light at a repetition frequency of 1/4 of the repetition frequency M The X-axis resonant scanner in the X-axis direction and the Y-axis resonant scanner that shakes the irradiation direction of the laser light in the Y-axis direction at a repetition frequency of 1/4 of the repetition frequency M, generates a pulsed laser The light is allocated to the elliptical orbit of each electrode pad of the position information memorized in the position information memory means. The elliptical orbit positioning means is made by moving the elliptical orbit generated by the elliptical orbit generating means to X in the X axis direction. An axis scanner and a Y-axis scanner that moves the elliptical orbit in the Y-axis direction can position the elliptical orbit to pass the processing object based on the position information of the electrode pads stored in the position information memory means Four electrode pads, and compared to the sine curve generated by the Y-axis resonant scanner, the sine curve generated by the X-axis resonant scanner has only a phase shift of π/2, which is ideal.

According to the laser processing method of the wafer of the present invention, it has: The position information memory step is to memorize the position information of each device formed on the plurality of electrode pads of each device together with the position information of each device on the wafer; the elliptical orbit generation step is to use each other and two adjacent As a group of 4 devices, an elliptical orbit containing a circle passing through 4 electrode pads arranged at the same position of each device is generated; the laser light irradiation step is to draw the elliptical orbit, For the positions of the electrode pads corresponding to the 4, pulse laser light is irradiated by pulse laser light irradiation means; and the elliptical orbit positioning step, which can pass the 4 electrodes corresponding to the next processing The elliptical track is positioned by the position of the bonding pad; while the wafer is relatively processed and fed with the pulsed laser light irradiation means, the laser light irradiation step and the elliptical track positioning step are sequentially implemented to form Through hole processing of the through hole, by this, in the formation of one through hole, it is possible to simultaneously perform the multiple electrode pads while maintaining the maximum repetition frequency (for example, 10kHz) that does not cause cracks. Implementation of through-hole processing to irradiate laser light can improve productivity.

In addition, by performing the laser beam irradiation step for the four devices constituting a group, the first two devices whose laser beam irradiation becomes the first time are partially processed through holes. Part of the through-hole processing is performed, and the laser beam is irradiated for the second time. The other two devices perform through-hole processing on the remaining unprocessed parts, thereby treating all the electrodes of the other two devices. The through hole of the solder pad is processed, By implementing the laser beam irradiation step, the two devices corresponding to all the electrode pads and through-hole processing are cut from the group, and the two devices that have not been through-hole processed partially and adjacent The two unprocessed devices in the processing feed direction are formed into a new group, the four devices contained in the new group are positioned on the elliptical orbit, and the laser light irradiation step and the ellipse are sequentially implemented The orbit positioning step is to follow the relative processing feed speed of the wafer and the laser beam irradiation means, and position the elliptical orbit through each position coordinate of the electrode pad to be processed next, so that the laser beam is irradiated When the direction is deviated, the angle of deflection adjustment can also be reduced, and the incident angle of the laser light to the wafer can be contained within the allowable range for proper processing.

In addition, according to the laser processing apparatus of the present invention, the structure includes holding means for holding the wafer on a plane defined by the X axis and the Y axis, and the wafer is a plurality of devices by dividing the predetermined line The division is formed on the surface; the laser beam irradiation means irradiates the wafer held by the holding means with the laser beam to perform processing, and is characterized by: position information memory means, which is related to the wafer The position information of the device together memorizes the position information of the plurality of electrode pads formed in each device; the elliptical orbit generation means uses 4 devices adjacent to each other and 2 devices as a group, according to the electrode Pad location information To generate an elliptical orbit containing a circle passing through 4 electrode pads arranged at the same position; an elliptical orbit positioning means which positions the elliptical orbit at a position corresponding to the 4 electrode pads to be processed ; And a laser beam irradiation means, which draws the elliptical orbit while irradiating pulse laser beams at positions corresponding to the four electrode pads, while processing and feeding the wafer and pulse laser beams relatively, The laser beam irradiation means and the elliptical orbit positioning means are actuated to form the through holes. Therefore, similarly to the above, when the laser beam is irradiated multiple times to form the through holes, it can be maintained during the formation of the through holes. It is possible to improve productivity by simultaneously performing through-hole processing for irradiating a laser beam to a plurality of positions where electrode pads are formed without causing cracks to be lower than the maximum repetition frequency.

1‧‧‧Laser processing device

2‧‧‧Stationary abutment

3‧‧‧Suction table mechanism

36‧‧‧Suction table

4‧‧‧Laser light irradiation unit

5‧‧‧Laser light irradiation method

52: Output adjustment means

53: mirror

54: Concentrator

6: Camera means

7: Means of generating elliptical orbits

71: Y-axis resonance scanner

72: X-axis resonance scanner

8: Elliptical orbit positioning method

81: X-axis scanner (acoustic optical element (AOD))

82: Y-axis scanner (acoustic optical element (AOD))

20: Semiconductor wafer

21: Channel

22: device

Fig. 1 is a perspective view of a laser processing apparatus that implements the processing method of a workpiece of the present invention.

Fig. 2 is a block diagram for explaining the laser beam irradiation means, the elliptical orbit generating means, and the elliptical orbit positioning means equipped in the laser processing apparatus shown in Fig. 1.

Fig. 3 is a block diagram of a control means equipped in the laser processing apparatus shown in Fig. 1.

4 is a plan view and a partly enlarged view of the semiconductor wafer processed by the laser processing apparatus shown in FIG. 1.

Fig. 5 is an explanatory view showing the through-hole processing of the first embodiment implemented by the present invention.

Fig. 6 is an explanatory diagram showing the operation of the elliptical orbit generating means shown in Fig. 2.

Fig. 7-1 is an explanatory diagram showing the through-hole processing according to the second embodiment of the present invention.

Fig. 7-2 is an explanatory diagram showing the through-hole processing according to the second embodiment of the present invention.

Hereinafter, a suitable first embodiment of the processing method of the present invention and the processing device for implementing the processing method will be described in detail with reference to the drawings.

1 shows a perspective view of a laser processing device 1 used to implement the wafer processing method of the present invention. The laser processing device 1 is provided with: a stationary base 2; and a suction table mechanism 3 attached to the stationary The base 2 is movably arranged in the X-axis direction indicated by the arrow X to hold the workpiece; and the laser light irradiation unit 4 is arranged on the stationary base 2.

The suction table mechanism 3 is provided with: a pair of guide rails 31, 31 which are attached to the stationary base 2 along the X axis The first slider 32 is movably arranged in the X-axis direction on the guide rails 31 and 31; the second slider 33 is movably attached to the first slider 32 The ground is arranged in the Y-axis direction indicated by the arrow Y, which is orthogonal to the X-axis direction; the cover base 35 is attached to the second slider 33 and is supported by the cylindrical member 34; and the suction table 36, It is used as a holding means to hold the processed objects.

The suction table 36 is provided with a suction suction cup 361 formed of a porous material having air permeability, and the workpiece is held by operating a suction means (not shown) on a holding surface on the upper surface of the suction suction cup 361.

The chuck table 36 configured in this way is rotated by a pulse motor (not shown) arranged in the cylindrical member 34. In addition, the suction table 36 is provided with a clamping device 362 for fixing a ring frame supporting the workpiece via a protective tape.

The first slider 32 is provided with a pair of guided grooves 321, 321 fitted to the pair of guide rails 31, 31 on the lower surface, and a pair of grooves formed in parallel along the Y-axis direction on the upper surface.的rails 322, 322. The first slider 32 configured in this manner is configured to be movable in the X-axis direction along the pair of guide rails 31 and 31 by being fitted to the pair of guide rails 31 and 31 by the guide grooves 321 and 321. The illustrated chuck table mechanism 3 includes an X-axis direction moving means 37 for moving the first slider 32 in the X-axis direction along a pair of guide rails 31 and 31. The X-axis direction moving means 37 is provided with a male screw 371 arranged in parallel between the pair of guide rails 31 and 31. And a pulse motor 372 for rotationally driving the male screw 371, and the male screw 371 is connected to the output shaft of the pulse motor 372. In addition, the male screw 371 is a through-female screw hole formed by screwing in a male screw block not shown, and the male screw block protrudes below the central portion of the first slider 32. Therefore, the male screw 371 is driven forward and backward by the pulse motor 372, and the first slider 32 is moved along the guide rails 31 and 31 in the X-axis direction.

The illustrated laser processing apparatus 1 is provided with an X-axis direction position detection means (not shown) for detecting the X-axis direction position of the chuck table 36 described above. The X-axis direction position detection means is composed of a linear scale (not shown) arranged along the guide rail 31, and is arranged on the first slider 32, along with the first slider 32 along the linear scale. It is made by the moving reading head not shown. The reading head of this X-axis direction position detection means sends a pulse signal of one pulse per 1 μm to the control means described later. Then, the control means described later calculates the input pulse signal, thereby detecting the position of the suction table 36 in the X-axis direction. In addition, when the pulse motor 372 is used as the drive source of the X-axis direction moving means 37, the X-axis direction of the chuck table 36 can also be detected by calculating the drive pulses of the control means described later to output a drive signal to the pulse motor 372. position. In addition, when a servo motor is used as the drive source of the X-axis direction moving means 37, the pulse signal output by a rotary encoder that detects the number of rotations of the servo motor is sent to the control means described later. The control means calculates The input pulse signal can thereby also detect the X-axis position of the chuck table 36, and the form of the means for detecting the X-axis position in the present invention is not particularly limited.

The second slider 33 is provided below and A pair of guided grooves 331, 331 in which the pair of guide rails 322, 322 on the upper surface of the first slider 32 are fitted, is configured by fitting the guided grooves 331, 331 to the pair of guide rails 322, 322 Can move in the Y-axis direction. The chuck table mechanism 3 shown in the figure includes a Y-axis direction moving means 38 for moving the second slider 33 in the Y-axis direction along a pair of guide rails 322 and 322 provided on the first slider 32. The Y-axis direction moving means 38 includes a driving source such as a male screw 381 arranged in parallel between the pair of guide rails 322 and 322, and a pulse motor 382 for rotationally driving the male screw 381. The male screw 381 is rotatably supported at one end by a bearing block 383 fixed to the upper surface of the first slider 32, and the other end is drive-connected to the output shaft of the pulse motor 382. In addition, the male screw 381 is a through-female screw hole formed in a male screw block not shown, and the male screw block (not shown) protrudes below the center portion of the second slider 33. Therefore, the male screw 381 is driven forward and backward by the pulse motor 382, whereby the second slider 33 is moved in the Y-axis direction along the guide rails 322 and 322.

The illustrated laser processing apparatus 1 is provided with a Y-axis direction position detection means (not shown) for detecting the Y-axis direction position of the second slider 33 described above. The Y-axis direction position detection means is the same as the above-mentioned X-axis direction position detection means. It consists of a linear scale (not shown) arranged along the guide rail 322, and is arranged on the second slider 33, and The block 33 is formed by a reading head (not shown) that moves along the linear scale. The reading head of the Y-axis direction position detection means sends a pulse signal of 1 pulse per 1 μm to the control means described later. Then, the control means described later calculates the input pulse signal to detect the Y-axis position of the second slider 33 Set. In addition, when the pulse motor 382 is used as the drive source of the Y-axis direction moving means 38, the Y-axis of the second slider 33 can also be detected by calculating the drive pulses of the control means described later to output a drive signal to the pulse motor 382 The location of the direction. In addition, when a servo motor is used as the drive source of the Y-axis direction moving means 38, the pulse signal output by the rotary encoder that detects the number of rotations of the servo motor is sent to the control means described later, and the control means calculates the input pulse signal In this way, the Y-axis direction position of the second slider 33 can also be detected.

The laser light irradiation unit 4 is provided with: a support member 41, which is arranged on the stationary base 2; a housing 42 which is supported by the support member 41 and extends substantially horizontally; Means 5, which is arranged on the housing 42; and the imaging means 6, which is arranged on the front end of the housing 42, detects the processing area to be processed by laser.

The imaging means 6 is an infrared illuminating means that irradiates infrared rays to the workpiece, and an optical system that captures the infrared irradiated by the infrared illuminating means, in addition to a normal imaging element (CCD) that takes images by visible light. And it is composed of an imaging element (infrared CCD) that outputs an electrical signal corresponding to the infrared ray captured by the optical system, and sends the captured image signal to the control means described later.

With reference to FIG. 2, the above-mentioned laser beam irradiation means 5 and the elliptical orbit generating means 7 and elliptical orbit positioning means 8 which are attached to the laser beam irradiation means 5 will be described. The illustrated laser light irradiating means 5 is configured to include: a pulsed laser light oscillator 51 that irradiates laser light at a repetition frequency M (for example, 40 kHz), and adjusting the oscillating amount of the pulsed laser light oscillator 51 The output adjustment means (attenuator) 52 of the pulse laser light output, and the mirror 53 used to change the direction of the irradiated pulse laser light toward the workpiece on the chuck table 36, and the A light concentrator 54 for collecting light on the semiconductor wafer 20 on the chuck table 36. In addition, the suction table 36 shown in FIG. 2 has the X-axis direction as the direction perpendicular to the plane described in the drawing, and the Y-axis direction as the left-right direction.

As shown in FIG. 2, the elliptical orbit generating means 7 is arranged between the pulse laser beam oscillator 51 and the concentrator 54 according to the position of the electrode pad stored in the control means 9 described later Information, the trajectory of the irradiation direction of the pulsed laser light oscillated by the pulsed laser light oscillator 51 will be seen from the back of the grouped 4 devices which are arranged in the same position by 4 electrode welding The elliptical orbit of the pad (in the present invention, a circular orbit in which the length of the short axis and the long axis of the ellipse are the same is naturally included), for example, is composed of a Y-axis resonance scanner 71 and an X-axis resonance scanner 72, the Y The axis resonance scanner 71 uses a frequency (for example, 10 kHz) of 1/4 of the repetition frequency M of the laser light oscillated by the laser light oscillating means to shake the irradiation direction of the laser light in the Y-axis direction. The axial resonance scanner 72 swings the irradiation direction of the laser light to the X-axis direction at a frequency (for example, 10 kHz) of 1/4 of the repetition frequency M.

The elliptical orbit positioning means 8 adjusts the elliptical orbit to position a person, and the elliptical orbit is formed by the elliptical orbit generating means 7 The trajectory of the irradiation direction of the pulsed laser light can pass through the position coordinates corresponding to the four electrode pads to be processed on the wafer, for example: the elliptical orbit generated by the elliptical orbit generating means 7 can be deflected and adjusted An X-axis scanner (acousto-optical element (AOD)) 81 in the X-axis direction, and a Y-axis scanner (acousto-optical element (AOD)) 82 that deflects the elliptical orbit and adjusts it in the Y-axis direction, and, Equipped with: a damper 83 that absorbs the laser light used when selectively stopping the irradiation of the laser light. The acousto-optical element (AOD) constituting the X-axis scanner 81 and the Y-axis scanner 82 is provided with: the deflection of the laser light passing through the acousto-optical element (AOD) is adjusted in accordance with the voltage applied by the control means 9 described later Angle deflection angle adjustment means, by the X-axis scanner 81, the elliptical orbit of the laser beam irradiation direction generated by the elliptical orbit generating means can be deflected to the X-axis direction. Similarly, by the Y-axis scanner The effect of 82 can make the elliptical orbit of the laser beam irradiation direction deviate to the Y-axis direction.

In addition, regarding the elliptical orbit generating means 7, the elliptical orbit positioning means 8 is not limited to the above-mentioned specific configuration, as long as it has the same function, it may be replaced with other known means. For example, each acoustooptic device (AOD) can be changed to a Piezo-scanner or galvano scanner that can obtain the same deflection function. In addition, the above-mentioned reflecting mirror 53 may be configured as a scanning mirror 53' that further adjusts and corrects the irradiation direction of the pulsed laser beam passing through the elliptical orbit positioning means 8.

The illustrated laser processing device 1 is equipped with the control shown in FIG. 3 System means 9. The control means 9 is constituted by a computer, and is equipped with: a central processing unit (CPU) 91 for arithmetic processing in accordance with a control program, a read-only memory (ROM) 92 for storing the control program, etc., and readable storage for the calculation results, etc. Random access memory (RAM) 93 for writing, and input interface 94, output interface 95.

FIG. 4 shows a plan view (lower section) of a semiconductor wafer 20 as a workpiece to be processed by the through-hole processing method of the present invention, and a part of the enlarged view showing four devices 22 adjacent to each other and two (Upper section). As shown in the figure, the semiconductor wafer 20 supported by the ring-shaped frame F via the protective tape T is ground on the back side of a substrate made of silicon with a thickness of 100 μm. The surface has a plurality of grooves arranged in a grid. The road 21 divides a plurality of areas, and devices 22 such as ICs, LSIs, etc. are formed in the divided areas, and the surface side on which the devices 22 are formed is stuck by the protective tape T. All the devices 22 have the same configuration. A plurality of electrode pads P1-20 are formed on the surface of each device 22, respectively. The electrode pads P1-20 are made of metal materials such as aluminum, copper, gold, platinum, nickel, etc., with a thickness of 1 to 5 μm.

The semiconductor wafer 20 is drilled with through holes for irradiating pulsed laser light from the back side of the substrate to the electrode pads according to the processing method of the present invention. However, in order to drill through holes in the semiconductor wafer 20, The laser processing device 1 shown in Fig. 1 is used. In addition, when the through hole is formed, the laser light is not limited to irradiating from the back side, and may be irradiated from the surface, that is, the side where the device is formed, and is not limited to this embodiment. The laser processing apparatus 1 shown in FIG. 1 is provided with a suction table 36 for holding a workpiece as described above, and a pair of The laser beam irradiating means 5 for irradiating the laser beam on the workpiece held on the suction table 36. The suction table 36 is configured to attract and hold the workpiece, and is processed by the X-axis direction moving means 37 described above. The feed mechanism moves the workpiece in the processing feed direction shown by the arrow X in FIG. 4, and the indexing feed mechanism formed by the Y-axis direction moving means 38 moves the workpiece in the arrow X Y indicates the indexing feed direction.

Hereinafter, a description will be given of a processing method of using the laser processing device 1 shown in FIG. 1 to form a through hole of a through hole that reaches the electrode pad of the device 22 formed in the semiconductor wafer 20 shown in FIG. 4.

First, the semiconductor wafer 20 is placed on the surface side of the chuck table 36 of the laser processing apparatus 1 shown in FIG. 1, and the semiconductor wafer 20 is sucked and held on the chuck table 36. Therefore, the semiconductor wafer 20 is held so that the back side forms an upper side.

As described above, the chuck table 36 for sucking and holding the semiconductor wafer 20 is positioned directly under the imaging means 6 by the processing feed mechanism. Once the chuck table 36 is positioned directly under the imaging means 6, in this state, the grid-shaped channels 21 formed in the semiconductor wafer 20 held by the chuck table 36 can be aligned with the X axis direction and the Y axis. In the method of arranging the direction at a predetermined position, the semiconductor wafer 20 held by the chuck table 36 is picked up by the imaging means 6, and image processing such as pattern matching is performed to perform alignment work. At this time, although the surface of the substrate on which the channel 21 is formed of the semiconductor wafer 20 is located on the lower side, the imaging means 6 uses infrared illuminating means, an optical system that captures infrared rays, and an imaging device that outputs electrical signals corresponding to infrared rays as described above. Components (infrared CCD), etc., so you can On the back side of the substrate, a channel 21 of a planned dividing line is formed through the pickup.

By performing the above-mentioned alignment operation, the semiconductor wafer 20 held on the chuck table 36 is positioned at a predetermined coordinate position on the chuck table 36. Here, in the processing method of the present invention, all the electrodes formed on each device 22 are stored together with the position information on the semiconductor wafer 20 of all the devices 22 formed on the surface of the substrate of the semiconductor wafer 20 The step of storing the position information of the position information on each device 22 of the pads P ₁ to P ₂₀ will be executed and stored in the random access memory (RAM) of the control means 9 of the laser processing device 1.

More detailed description of the above-mentioned location information memory steps. As shown in the lower part of FIG. 4, in the present embodiment, each device 22 formed on the semiconductor wafer 20 is given position information for specifying the position on the semiconductor wafer 20. It is defined as the X axis, and the vertical direction is defined as the Y axis. From the leftmost device to the right, it is defined as X ₁ , X ₂ , X ₃ …, Xn, and from the top to the bottom as Y ₁ , Y ₂ , Y ₃ …, Yn. Therefore, in the upper paragraph, the position coordinates of each device 22 are enlarged. The upper left device 22 is defined as (X ₁ , Y ₄ ), the upper right device 22 is defined as (X ₂ , Y ₄ ), and the lower right The device 22 is defined as (X ₂ , Y ₅ ), and the device 22 on the lower left is defined as (X ₁ , Y ₅ ).

In addition, in each device 22 of the present embodiment, the first electrode is arranged in a direction (Y-axis direction) orthogonal to the machining feed direction (X-axis direction) in a state of being arranged on the chuck table 36 The pad row L1 and the second electrode pad row L2 are formed, and the position information indicating the position of each device 22 of each electrode pad P ₁ to P ₂₀ is defined. More specifically, if the device 22 (X ₁ , Y ₄ ) on the upper left side of FIG. 4 is viewed, for example, the X coordinates of the electrode pads P ₁ to P ₁₀ constituting the first electrode pad row L1 on the left Defined as x ₁ , the X coordinate of the electrode pads P ₁₁ to P ₂₀ constituting the second electrode pad array L2 on the right is defined as x ₂ , which will constitute the first electrode pad array L1 and the second electrode pad array L2 The Y coordinates of each electrode pad P ₁ ~P _{20 are} defined as y ₁ , y ₂ , y ₃ … y ₁₀ from the top to the bottom. That is, the positions of the electrode pads P ₁ to P ₁₀ arranged below the first electrode pad array L1 on the left side of the device 22 (X ₁ , Y ₄ ) in the enlarged view shown in the upper part of FIG. 4 Information is respectively defined as (x ₁ , y ₁ ), (x ₁ , y ₂ ), (x ₁ , y ₃ )..., (x ₁ , y ₁₀ ), from the second electrode pad row L2 on the right The position information of each electrode pad P ₁₁ ~ P ₂₀ arranged from top to bottom is defined as (x ₂ , y ₁ ), (x ₂ , y ₂ ), (x ₂ , y ₃ )...(x ₂ , y ₁₀ ). In addition, the electrode pads P ₁ to P _{20 of} all the devices 22 are given position information according to the same definition. Thus, for example, the four devices 22 (X ₁ , Y ₄ ), (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), (X ₁ , Y ₅ ) shown in the upper part of FIG. 4 a first electrode pad of the electrode pad row L1 uppermost location pad P all become ₁ is (x _1, y _1). Accordingly, the four upper left of the apparatus is illustrated in the electrode pad P ₁ is the formation of "co-located electrode pad."

As described above, in the processing method of the present invention, the position information formed in each device 22 is stored together with the above-mentioned position information on the semiconductor wafer 20 of all devices 22 formed on the surface of the substrate of the semiconductor wafer 20 One of the above-mentioned position information on each device 22 of all electrode pads The location information memory step will be implemented. Then, the semiconductor wafer 20 held on the chuck table 36 is positioned at a predetermined coordinate position on the chuck table 36 by the above-mentioned alignment operation. Therefore, the laser light is required to be placed on the semiconductor wafer 20. The coordinate positions of all electrode pads on the suction table are automatically specified.

Once the alignment is performed as described above and the position information memory step is performed, the elliptical orbit generation step will be performed by the elliptical orbit generation method. For the sake of convenience, the steps of generating the elliptical orbit are clearly explained, and the four devices 22 (X ₁ , Y ₄ ), (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), (X ₁ , Y ₅ ) is used as an example for laser processing.

In the processing method of the present invention, four devices 22 in two rows and two adjacent to each other are grouped together, and laser processing is performed on the four devices 22 at the same time. First, the processing and feeding means (X-axis direction moving means 37) and the indexing feeding means (Y-axis direction moving means 38) of the chuck table 36 holding the semiconductor wafer 20 are actuated without the elliptical orbit generating means described later. In the state of the shaking action of 7 and the deflection of the elliptical orbit positioning means 8, it is assumed that when the laser light oscillates from the laser light oscillator 51, it can be formed in the laser light irradiated by the point O in Fig. 5(a) The position shown in ₁ moves the suction table 36. In addition, this point O ₁ is located in each of the devices 22 (X ₁ , Y ₄ ), (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), (X ₁ , Y ₅ ) and is initially subjected to through-hole processing The center of the four electrode pads P ₁ (x ₁ , y ₁ ) arranged at the same position on each device 22 of.

If the point O ₁ is positioned immediately below the laser beam applying means 5, the generating means 7 by the elliptical orbit, the pad P1 is the position information memory of the electrode pads 4, laser light generated from the oscillator 51 is depicted the irradiation direction of the laser light irradiation will pass four electrode pad P ₁ of the elliptical orbit is elliptical orbit. More specifically, by shaking the scanning mirror 711 of the Y-axis resonance scanner 71 at 10 kHz, the irradiation direction of the laser beam is moved back and forth in the Y-axis direction (refer to FIG. 6(a)), and the X-axis resonance scanner The scanning mirror 721 of the 72 oscillates at the same frequency as the Y-axis resonance scanner 71 at 10 kHz, thereby moving the irradiation direction of the laser light back and forth in the X-axis direction (see FIG. 6(b)). Here, as shown in FIG. 6, the sine curve drawn by the shaking of the X-axis resonance scanner 721 is a sinusoid drawn by the shaking of the scanning mirror 711 of the Y-axis resonance scanner 71. Slowly π/2 phase is shaken, and the laser beam irradiated from the laser beam oscillator 51 can pass through the four electrode pads P1 (x1, y1) that become the same position coordinates on each device 22. In the above method, the oscillation width of the scanning mirror 711 of the Y-axis resonance scanner 71 and the scanning mirror 721 of the X-axis resonance scanner 72 is set.

Once the elliptical orbit can be generated in such a way that the irradiation direction of the pulsed laser light can pass through the four electrode pads P ₁ , the pulsed laser light will pass through the suction table 36 of the four electrode pads P ₁ The timing of the coordinate position on the upper side is irradiated with pulsed laser light by pulsed laser light irradiation means 5 (pulse laser light irradiation step). More specifically, the repetition frequency of the pulsed laser beam oscillated from the laser beam oscillator 51 is set to be 40 kHz, which is 4 times the oscillation frequency of the scanning mirror of the X-axis and Y-axis resonant scanner, 10 kHz, relative to the Y-axis The oscillation period of the resonant scanner is adjusted in such a way that the laser light can be oscillated at the timing when the phase becomes π/4, 3π/4, 5π/4, 7π/4, and the pulse laser light irradiation timing is adjusted corresponding to the electrode pad position coordinates P _1, for the back surface of the semiconductor wafer 20, a plurality of repeated pulses of laser light irradiation, the through holes penetrated. When forming the through holes as shown in the processing conditions described later, pulse laser beams are irradiated 10 times in total to form through holes from the back surface of the semiconductor wafer 20 to the electrode pads formed on the surface side. In addition, in the present embodiment, the finished part of the through hole is indicated by ●, and the unprocessed part is indicated by ○.

In addition, each processing condition of the above-mentioned through hole processing is set as follows.

[Wafer Conditions]

Channel spacing: X axis direction 5mm, Y axis direction 7mm

Electrode pads: 10 in the Y-axis direction, 2 rows in the X-axis direction = 20

Through hole formation: pulse laser 10 times/electrode pad

[Laser processing equipment conditions]

Wavelength of laser light: 355nm

Average output: 4W

Repetition frequency: 40kHz

Point diameter: φ10μm

Processing feed speed: 500mm/sec

Once the through-hole processing is performed according to the above conditions, the irradiation direction of the pulsed laser light will draw an elliptical orbit at a frequency of 10kHz, and the irradiation direction of the pulsed laser light will be irradiated at a frequency of 40kHz during one round of the elliptical orbit. pulse oscillating laser light will be four times the electrode welding at a frequency of 10kHz pad P is _a pulsed laser beam is irradiated. That is, the welding electrode pads P ₁ 4 substantially simultaneously at a frequency of substantially 10kHz to the through hole processing embodiment.

Only a predetermined number of times (10 times under the above conditions) are irradiated with pulsed laser light to the electrode pads P _{1 of} the first four devices mentioned above, and the formation of through holes for the four electrode pads P ₁ is completed , Apply a predetermined voltage to the acousto-optical element (AOD) of the Y-axis scanner 82 of the elliptical orbit positioning means 8, adjust the deflection angle of the pulsed laser light in the Y-axis direction, thereby moving the center O _{1 of the} elliptical orbit to 0 ₂ (Refer to Figure 5(b)), implement the elliptical orbit positioning step in such a way that the irradiation direction of the pulsed laser light can pass through the four electrode pads P ₂ (x ₁ , y ₂ ) to be processed next, and then, the P electrode _{pad. 1} Similarly, for the embodiment of the electrode pads 4 P ₂ pulsed laser beam irradiation step pad.

In this way, the pulse laser light irradiation step and the elliptical orbit positioning step are carried out in sequence. Once the through holes of the electrode pads P ₁ ~ P ₁₀ of the first electrode pad column L1 are processed, as shown in Figure 5(c) As shown, the center of the elliptical orbit is moved to O ₂₀ , and the pulse laser beam can pass through the four electrode pads P ₂₀ (x ₂ , y ₁₀₎ of the second electrode pad array L2 to be processed next. ) To implement the elliptical orbit positioning step. Then, by performing the above-mentioned pulse laser light irradiation step, once the through holes for the four electrode pads P ₂₀ (x ₂ , y ₁₀ ) are processed, the Y-axis scanner of the elliptical orbit positioning means 8 The AOD of 82 applies a predetermined voltage to adjust the deflection angle of the pulsed laser light in the Y-axis direction, thereby sequentially moving the elliptical orbit in the direction of the electrode pad P ₁₁ (upper in the figure). The track positioning step and the pulse laser light irradiation step are shown in Figure 5(d). The center of the elliptical track is positioned at O ₁₁ , so that all electrode pads P _{11 of} the electrode pad row L2 The through hole of ~P ₂₀ is finished. With the above, for the four devices 22 (X ₁ , Y ₄ ), (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), (X ₁ , Y ₅ ), all electrode pads P ₁ The through hole of ~P ₂₀ is finished. In addition, during the elliptical orbit positioning step and the pulse laser beam irradiation step, the processing feed of the moving means 37 in the X-axis direction will continue at the above processing feed speed, in order to correspond to the processing feed of the semiconductor The relative position of the wafer 20 and the pulse laser beam irradiation means 5 changes, and the X-axis scanner 81 adjusts the deflection angle in the X-axis direction, so that the irradiation direction of the pulse laser beam will always follow each device. Are positioned on the four electrode pads of the processing object.

Once the four devices 22 (X ₁ , Y ₄ ), (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), (X ₁ , Y ₅ ) are formed by the action of the above-mentioned processing and feeding means When the through holes of all the electrode pads P ₁ ~ P ₂₀ are processed, the four unprocessed devices 22 (X ₃ , Y ₄ ), (X ₄ , Y ₄ ) adjacent to the processing feed direction , (X ₃ , Y ₅ ), (X ₃ , Y ₅ ) will move to the four devices 22 (X ₁ , Y ₄ ), (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), (X ₁ , Y ₅ ) the position where the through hole machining is started. Therefore, set a new group with the four unprocessed devices 22 (X ₃ , Y ₄ ), (X ₄ , Y ₄ ), (X ₃ , Y ₅ ), (X ₄ , Y ₅ ), To the X-axis scanner 81 of the elliptical orbit positioning means 8, the Y-axis scanner 82 applies a predetermined voltage, thereby biasing and adjusting the irradiation direction of the laser light forming the elliptical orbit so that it can pass through the devices that are arranged in each raw material The method of adjusting the electrode pads P ₁ (x ₁ , y ₁ ) at the same position in the first electrode pad row of 22 is the same as the above for the 4 unprocessed devices 22 set as a new group Through hole processing, the through hole processing is completed for all the electrode pads P ₁ to P ₂₀ of the device 22 of the new four. Then, by repeating such processing, the through-hole processing is completed for all the devices 22 arranged in the processing feed direction.

If the through-hole machining of all the devices 22 arranged in the processing feed direction is performed, the Y-axis direction moving means 38 moves the suction table 36 in the indexing feed direction to position the laser beam irradiation means 5 At the position where the unprocessed device 22 is provided, the same through-hole processing as described above is sequentially performed for the new row. By repeating it, the through hole processing corresponding to the positions of the electrode pads P ₁ to P ₂₀ on all the devices 22 arranged on the semiconductor wafer 20 is completed.

In addition, the plan view of the semiconductor wafer 20 in FIG. 4 is like the area indicated by H. Based on the relationship of efficiently arranging the device 22 on the circular semiconductor wafer 20, it may not be possible to connect each other with two Four adjacent devices form a group. In this case, for example, three devices 22 (X ₄ , Y ₁ ), (X ₃ , Y ₂ ), (X ₄ , Y ₂ ) in the area indicated by the H form a group. Then, laser processing is performed according to the same procedure as the through hole processing performed for the above four devices 22, but the area adjacent to the device 22 (X ₄ , Y ₁ ), (X ₃ , Y ₂ ) is also That is to say, the area where the device is lacking is such that the pulsed laser light is not irradiated. The Y-axis scanner 82 acts on the damper that absorbs the laser light at the timing when the pulsed laser is irradiated to the area where the device is lacking. 83 adjusts the deflection of the laser light, and stops the irradiation of the laser light toward the light collector 54. In this way, the program for performing through-hole processing for four devices can be implemented roughly as it is.

Furthermore, assuming that the number of devices 22 arranged in the processing feed direction on the semiconductor wafer 20 is not an even number, at the beginning or the end of the processing feed direction, it is impossible to form a group with 4 devices, and 2 Examples of groups of devices to form. In this case, by the same means as described above, for areas where the device is lacking, the irradiation direction of the laser light is deviated toward the damper 83 every time, and the irradiation of the laser light from the light collector 54 is stopped. With this, it is possible to perform through-hole processing substantially the same as in the case of forming a group with the above-mentioned four devices for a group formed by two devices.

Since the above-mentioned first embodiment of the present invention is configured as described above, it is possible to perform the simultaneous implementation while maintaining the maximum repetition frequency (for example, 10 kHz) that does not cause cracks in the formation of one through hole. Through hole processing where laser light is irradiated to the positions corresponding to the plural electrode pads can improve productivity. In addition, in this embodiment, the repetition frequency of the laser beam oscillator 51 is set to 40 kHz, and the oscillation frequency in the X-axis direction and Y-axis direction of the elliptical orbit generating means is set to 10kHz, but the present invention is not limited to this. As long as the repetition frequency M of the pulsed laser light oscillated by the laser light oscillator 51 is set to a multiple of 4, the shaking frequency becomes the repetition frequency M by means of elliptical orbit generation. 1/4, it is possible to implement control that achieves the same effects as in the present embodiment.

Hereinafter, the second embodiment of the present invention will be described. In addition, in this second embodiment, the same laser processing apparatus 1 as the above-mentioned first embodiment can be used. Only the laser beam irradiation means 5 and the elliptical orbit positioning means 8 have different through-hole processing procedures. Only the different points are explained, and the explanation for the same points is omitted.

The laser beam irradiation step of the second embodiment is the same as that of the first embodiment. The electrode pads at the same position of the four devices 22 included in the same group are irradiated sequentially while drawing an elliptical orbit. The points of the laser beam irradiating step of the irradiating light are common. However, in this embodiment, the laser beam irradiation step is performed for the four devices constituting a group, and the laser beam irradiation becomes the first two devices partially The through-hole processing is performed, the through-hole processing is partially performed, and the laser beam is irradiated for the second time. The other two devices perform through-hole processing on the remaining unprocessed parts, thereby making the other two After the through holes of all the electrode pads of each device are processed, the laser beam irradiation step is performed to cut the two devices corresponding to all the electrode pads and the through holes are processed from the group to The two devices that have not been partially processed through hole processing and the two unprocessed devices adjacent to the machining feed direction form a new group. The four devices contained in the new group The point of positioning the elliptical orbit, and sequentially implementing the laser light irradiation step and the elliptical orbit positioning step is different from the first embodiment.

Regarding the laser beam irradiation step and the elliptical orbit positioning step of the second embodiment, similar to the first embodiment, the case where the through-hole processing is performed on each device 22 arranged in the enlarged area in the upper part of FIG. 4 , More specifically. In addition, in this embodiment, by sequentially attaching numbers to the plural electrode pads arranged in each device, they are divided into the odd-numbered first electrode pad group and the even-numbered second electrode pad group. Electrode pad group, set the position information, and execute the laser light irradiation step for the 4 devices forming a group, the laser light irradiation step is the first for the 4 devices The electrode pad group and the unprocessed electrode pad group of the second electrode pad group are irradiated with pulsed laser light while drawing an elliptical orbit, thereby welding all the electrodes corresponding to the two devices After the through-hole processing of the pad is completed, cut the two devices that have been processed for all the through-holes of the electrode pads from this group, and perform it on either the first electrode pad group or the second electrode pad group The two devices for through-hole processing and the two unprocessed devices adjacent to the machining feed direction form a new group, and the four devices included in the new group locate the elliptical orbit. First, the unprocessed electrode pad group in the second electrode pad group is subjected to the laser light irradiation step and the elliptical orbit positioning step, so that the through holes for the two devices are processed in sequence.

As shown in Figure 7-1(a), in the second embodiment, four devices 22 (X ₁ , Y ₄ ), (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), ), (X ₁ , Y ₅ ) to form a group, and two devices 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ) to form a group. In other words, as there are virtual devices 22', 22' on the left side of the figure of device 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ) to form a group, the elliptical orbit will be positioned on device 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ) electrode pads are partially irradiated in order to perform the first through hole processing of the device 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ) Pulse laser light to perform through-hole processing. In addition, in the timing of irradiating the pulsed laser light on the virtual devices 22', 22', the Y-axis scanner 82 and the damper 83 are used to stop the laser light irradiation from the light collector 54.

Here, the case where the above-mentioned "partially" through hole processing is performed will be explained. First, as for the plural electrode pads arranged on each device 22, like the _one shown in FIG. 4, numbers are given in order like P ₁ to P ₂₀ . Then, according to each number, the electrode pads (P ₁ , P ₃ , P ₅ , P ₇ , P ₉ , P ₁₁ , P ₁₃ , P ₁₅ , P ₁₇ , P ₁₉ ) are grouped together to be the odd A group of electrode pads is grouped into the even-numbered electrode pads (P ₂ , P ₄ , P ₆ , P ₈ , P ₁₀ , P ₁₂ , P ₁₄ , P ₁₆ , P ₁₈ , P ₂₀ ) and set as the first Two electrode pad group. Moreover, not all the electrode pads P ₁ to P ₂₀ provided in each device 22 are formed with through holes in sequence, but as shown in FIG. 7-1(a), for the odd-numbered electrode pads That is, only the electrode pads of the first electrode pad group are processed in order through holes.

If in this way, only the first electrode pad group of the device 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ), that is, "partially" through-hole processing, is stored in the control means 9 The control program to cut the virtual device 22', 22' from the group to partially implement the device 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ) and adjacent to the device 22 (X _{1, Y 4), (X} 1, Y 5) of the machining feed direction of unprocessed means _{22 (X 2, Y 4)} , (X 2, Y 5) to form a new group. Then, the laser light irradiation means 5 and the elliptical orbit positioning means 8 are activated, and the laser light irradiation step is further implemented. Here, regarding the first electrode pad group composed of the odd-numbered electrode pads of the device 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ), the through hole processing has been performed, so this time In any of the four devices, the through hole processing is also performed on the second electrode pad group composed of the unprocessed even-numbered electrode pads. After the processing is completed, as shown in Fig. 7-2(b), it corresponds to all of the devices 22 (X ₁ , Y ₄ ) and (X ₁ , Y ₅ ) that are subjected to the second through-hole processing The through holes of electrode pads P ₁ ~P ₂₀ are processed. On the other hand, the device 22 (X ₂ , Y ₄ ), (X ₂ , Y ₅ ) added to the new group is the first laser light irradiation, and only for the even-numbered electrode The second electrode pad group formed by the pads is irradiated with laser light, only partially forming through holes.

Once the above-mentioned through-hole processing is completed, all the through-hole processed devices 22 (X ₁ , Y ₄ ), (X ₁ , Y ₅ ) are cut from the group, so that only the second electrode pad group is connected. The hole processing device 22 (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), and the two unprocessed devices 22 (X ₃ , Y ₄ ), (X ₃ , Y) adjacent to the processing feed direction ₅ ) To form a new group, perform the same through hole processing as above. That is, through the first through-hole processing of the device 22 (X ₂ , Y ₄ ), (X ₂ , Y ₅ ), the second electrode pad group composed of the even-numbered electrode pads The through-hole processing has already been performed, so this time through-hole processing is performed on the first electrode pad group composed of the odd-numbered electrode pads. After the processing is completed, as shown in Fig. 7-2(c), all the electrodes corresponding to the device 22 (X ₂ , Y ₄ ), (X ₂ , Y ₅ ) of the second through-hole processing The processing of pads P ₁ to P ₂₀ is complete. In addition, by repeating such processing in sequence, it is possible to perform through-hole processing for the device 22 arranged in the processing feed direction. However, when the through-hole processing for the last two devices 22 grouped is completed, due to The adjacent unprocessed device does not exist. Therefore, it is possible to process the two devices 22 (X ₁ , Y ₄ ) and (X ₁ , Y ₅ ) that were initially processed as virtual devices 22' and 22', so It is assumed that the virtual devices 22', 22' locate the elliptical orbits to form a group and perform through-hole processing. With this, the through holes of all the devices 22 arranged in the machining feed direction can be processed.

According to the second embodiment described above, the through-hole processing for the four devices is performed while the through-hole processing for the two devices is completed sequentially. Therefore, the through-hole processing for the four devices is performed simultaneously For comparison with the completed first embodiment, the X-axis scanner 81 is used to adjust the deflection angle of the laser beam so that it can follow the semiconductor wafer 20 that is being processed and fed in the X-axis direction. The incident angle of the circular laser beam is within the allowable range and proper processing is performed.

In addition, in the above-mentioned second embodiment, as a means of "partially" performing through-hole processing on the two devices that are irradiated with laser light for the first time, electrode welding is divided into odd-numbered or even-numbered electrodes. The through-hole processing is performed by using a pad, but the means of performing the through-hole processing "partially" is not limited to this. For example, instead of performing through-hole processing on the odd-numbered electrode pads in the above second embodiment, and perform through-hole processing on the electrode pads P ₁ to P ₅ , P ₁₁ to P ₁₅ , and perform the processing for the remaining electrodes Welding pads P ₆ ~ P ₁₀ , P ₁₆ ~ P ₂₀ through-hole processing can achieve the same effect. and. In the second embodiment, 20 electrode pads are arranged in two rows L1 and L2, but the arrangement of the electrode pads is not limited to this. There are also cases where only one row of electrode pads are provided for the device, or it may be assumed that there are 10 in one row and 2 in the other row. Various arrangements such as the arrangement pattern of the electrode pads can also be the same as the second row. In the embodiment, the electrode pads are divided into two groups to partially perform through-hole processing.

Moreover, when performing through-hole processing corresponding to one electrode pad in the above-mentioned laser processing conditions, the output can be adjusted so that the through-hole processing can be irradiated 10 times with pulsed laser light, so it can be replaced by The second embodiment is generally divided into odd-numbered and even-numbered to perform through-hole processing, but only 5 times each of which performs laser sequentially on all the electrode pads of the 4 devices forming a group of 1 Processing of light irradiation. In this way, the two devices that are the first irradiation of the laser beam are processed only partially for each electrode pad. Then, by irradiating the second laser beam to the other two devices that have been irradiated with the laser beam five times, the through holes for all the electrode pads of the other two devices Finished processing. As a result, as in the above-mentioned second embodiment, the through holes for the two devices can be processed in sequence, and the same effects as those obtained in the above-mentioned second embodiment can be obtained without changing the first time. And the second laser beam irradiation method can simplify the processing equipment. In this way, the means for "partially" performing the through-hole processing can adopt various modifications.

Furthermore, in the above-mentioned embodiment, the position information of each device of the wafer stored in the control means and the position information of each device of the plural electrode pads formed on each device are described as "device 22(X ₁ , Y ₄ ), (X ₁ , Y ₅ )", or "P ₁ ~P ₁₀ (x ₁ , y ₁ ), (x ₁ , y ₂ ), (x ₁ , y ₃ )..., (x ₁ , y ₁₀ )”, but the position information of each device and the position information of each device of the plural electrode pads formed on each device are not limited to this. The position information of each device is based on the device selected on the wafer to form a group, or to separate the processed devices while performing the through-hole processing, as long as it is to distinguish the device on the wafer Group each other, or separate which device from the group, and the available information is sufficient, either in any form. In addition, the format of the position information of each device of the plural electrode pads formed on each device is the same as the above, as long as the position of each device of the corresponding electrode pad can be distinguished from the position of other electrode pads. , Whichever form can be used.

5‧‧‧Laser light irradiation method

7‧‧‧Oval orbit generation method

8‧‧‧Elliptical orbit positioning method

20‧‧‧Semiconductor Wafer

36‧‧‧Suction table

51‧‧‧Pulse laser light oscillator

52‧‧‧Output adjustment method

53‧‧‧Mirror

53’‧‧‧Scanning mirror

54‧‧‧Concentrator

71‧‧‧Y-axis resonance scanner

72‧‧‧X-axis resonance scanner

81‧‧‧X-axis scanner (acoustic optical element (AOD))

82‧‧‧Y-axis scanner (acoustic optical element (AOD))

83‧‧‧Dampener

711、721‧‧‧Scanning mirror

Claims (8)

A wafer processing method, a processing method in which a plurality of devices divide a wafer formed on the surface by a predetermined dividing line, and is characterized by including: a position information memory step, which is related to the position information of each device of the wafer The position information of each device of the plurality of electrode pads formed on each device is stored together; the elliptical orbit generation step is to take each other and 2 adjacent 4 devices as a group, and generate a group including through the The elliptical trajectory of the four electrode pads at the same position in each device; the laser beam irradiation step is to trace the elliptical trajectory while targeting the positions of the four electrode pads corresponding to the four electrode pads by pulse The laser light irradiation means irradiate the pulsed laser light; and the elliptical orbit positioning step, which is to position the elliptical orbit in a way that corresponds to the positions of the four electrode pads to be processed next; while processing them relatively For the wafer and pulse laser light irradiation means, the laser light irradiation step and the elliptical orbit positioning step are performed sequentially, and the through hole processing for forming the through hole corresponding to the electrode pad is performed on the wafer . For example, in the method of processing a wafer in the scope of the patent application, in the step of irradiating the laser light, in a state in which the elliptical orbit can pass through the four electrode pads, a plurality of Pulse laser light is irradiated to the through hole processing corresponding to the positions of the four electrode pads. For example, the wafer processing method of item 1 or 2 of the patent application, which In this case, by performing the laser beam irradiation step for the four devices constituting a group, the two devices whose laser beam irradiation becomes the first time are partially processed through holes. Part of the through-hole processing is performed, and the laser beam is irradiated for the second time. The other two devices perform through-hole processing on the remaining unprocessed parts, thereby treating all the electrodes of the other two devices. After the through-hole processing of the pad is completed, by performing the laser light irradiation step, the two devices corresponding to all the electrode pads and the through-hole processing are cut from the group, so that the through-hole is not partially performed The two devices processed and the two unprocessed devices adjacent to the processing feed direction are formed into a new group, and the elliptical orbits are positioned for the four devices contained in the new group, and the elliptical orbits are sequentially implemented The laser light irradiation step and the elliptical orbit positioning step. For example, the method of processing a wafer in the third item of the scope of patent application, wherein, by sequentially assigning numbers to plural electrode pads arranged in each device, they are divided into odd-numbered first electrode pad groups and The position information is set by the even-numbered second electrode pad group, and the laser light irradiation step is for any unprocessed among the first electrode pad group and the second electrode pad group of the four devices One electrode pad group is irradiated with pulsed laser light while drawing an elliptical orbit, so that the through holes of all the electrode pads corresponding to the two devices are processed, and all the electrodes are cut from the group. The two devices where the through-holes of the pads are processed are the two devices that are through-hole-processed only in either the first electrode pad group or the second electrode pad group, and are adjacent to the machining feed direction 2 unprocessed devices to form a new group, the new group contains The elliptical orbit is positioned by the four devices of the first and second electrode pad groups, and the laser light irradiation step and the elliptical orbit positioning step are performed for the unprocessed electrode pad groups among the first and second electrode pad groups, and the elliptical orbit positioning steps The through hole of the device is finished. For example, the wafer processing method of the first or the second item of the scope of the patent application, in which the outer periphery of the wafer cannot be grouped by 4 devices adjacent to each other and 2 devices, by less than 4 The individual devices can be grouped together to stop the laser beam irradiating the areas lacking in the device. A laser processing device, comprising: holding means for holding a wafer on a plane defined by the X-axis and Y-axis, and the wafer is formed on the surface by dividing a predetermined line into a plurality of devices; The ray irradiating means irradiates the wafer held by the holding means with laser light to perform processing, and is characterized by having: position information memory means, which is memorized together with the position information of each device of the wafer The position information of a plurality of electrode pads formed in each device; an elliptical orbit generating means, which is a group of 4 devices adjacent to each other and 2 devices, and generates according to the position information of the electrode pads An elliptical orbit including a circle passing through four electrode pads arranged at the same position; an elliptical orbit positioning means, which positions the elliptical orbit at a position corresponding to the four electrode pads to be processed; and Laser beam irradiation means, which draws the elliptical orbit while irradiating pulsed laser beams at the positions corresponding to the four electrode pads, while processing and feeding the wafer and pulsed laser beams relative to each other while operating The laser light irradiation means and the elliptical orbit positioning means form a through hole. For example, the laser processing device of item 6 of the scope of patent application, wherein the laser light irradiation means includes: an oscillator, which oscillates pulsed laser light at a repetition frequency M that is a multiple of 4; and a concentrator, which The pulsed laser light oscillated by the oscillator is concentrated on the wafer held by the holding means. The elliptical orbit generating means is arranged between the oscillator and the concentrator, with a repetition frequency of M An X-axis resonance scanner with a repetition frequency of 1/4 to shake the irradiation direction of the laser light to the X-axis direction, and a repetition frequency of 1/4 of the repetition frequency M to shake the irradiation direction of the laser light to the Y-axis The direction of the Y-axis resonant scanner is formed to generate an elliptical orbit that distributes the pulsed laser light to each electrode pad whose position information is stored in the position information memory means. The elliptical orbit positioning means is formed by: The elliptical orbit generated by the orbit generating means is composed of an X-axis scanner that moves the elliptical orbit in the X-axis direction and a Y-axis scanner that moves the elliptical orbit in the Y-axis direction. According to the electrode pads stored in the position information storage means Position information, the elliptical orbit is positioned to pass the 4 electrode pads of the processing object. For example, the laser processing device of item 7 of the scope of patent application, which For the sine curve generated by the Y-axis resonant scanner, the sine curve generated by the X-axis resonant scanner is only π/2 phase shifted.

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