JP6483541B2 - Processing method of package substrate - Google Patents

Description

  The present invention relates to a processing method for a package substrate, in which a package substrate in which devices are respectively arranged in a plurality of regions partitioned by a predetermined division line formed in a lattice pattern on the surface of a thermal diffusion substrate is divided along the predetermined division line.

  Devices such as ICs, LSIs, and power devices are sometimes used by being disposed on a heat diffusion substrate called a heat sink so as not to cause a decrease in function due to heat generation. Thus, the package device in which the devices are arranged on the heat diffusion substrate is manufactured by dividing the package substrate in which a plurality of devices are arranged on the surface of the heat diffusion substrate. Note that the thermal diffusion substrate is formed of ceramics having high thermal conductivity such as aluminum nitride in addition to metals such as stainless steel and copper.

  In addition, a plurality of devices are arranged on the surface of the thermal diffusion substrate via a bonding material at a predetermined interval that becomes a line to be divided in the package substrate. In addition, the division | segmentation scheduled line on a thermal-diffusion board | substrate and an outer periphery may be formed by covering with a synthetic resin.

  In order to divide the package substrate along the planned division line and divide the package substrate into individual package devices, a method of irradiating a laser beam along the planned division line is used (for example, see Patent Document 1). A method of cutting with a cutting blade instead of a laser beam is also known.

Japanese Patent Laying-Open No. 2015-037145

  When considering the problem in production efficiency when configuring the package substrate, a thermal diffusion substrate as large as possible is prepared, and a power supply substrate is arranged on the thermal diffusion substrate to configure the package substrate. It is better to divide the package substrate into individual devices.

  However, if a large-sized package substrate, for example, a package substrate having a size of 700 mm × 500 mm is prepared and an attempt is made to perform a dividing process in which each device is divided by one cutting device, the corresponding large package substrate is handled. A cutting apparatus that can divide up to individual devices must be prepared. In particular, when the suction holding portion is configured in the chuck table corresponding to each of the divided devices, the chuck table itself There is a problem that the size and complexity of the processing apparatus increase, and the cost of the processing apparatus increases.

  The present invention has been made in view of the above problems, and its main technical problem relates to a processing method for dividing a package substrate on which a device is arranged on a thermal diffusion substrate, and increases the size of the chuck table. An object of the present invention is to provide a method of processing a package substrate that can be suppressed.

  In order to solve the above-mentioned main technical problem, according to the present invention, a package substrate in which a plurality of devices are arranged on a surface of a thermal diffusion substrate in an area partitioned by a vertical division line and a horizontal division line is individually provided. A package substrate processing method for dividing the package substrate into four package devices, wherein the center vertical division line and the central horizontal division line of the package substrate are cut to obtain an upper left substrate, an upper right substrate, a lower left substrate, and a lower right substrate. A quarter substrate generating step of dividing the quarter substrate, and relief grooves are formed corresponding to the plurality of planned vertical and horizontal division lines in the divided quarter substrate, and the relief grooves A ¼ substrate placing step of placing the ¼ substrate on a chuck table in which holding portions for sucking and holding individual package devices are formed in each of the regions partitioned by The imaging means for imaging at least one corner of the quarter substrate images the corner of the quarter substrate placed on the chuck table, and from the state of the corner thus imaged, the upper left A 1/4 substrate discriminating step for discriminating which of the four quarter substrates of the substrate, the upper right substrate, the lower left substrate, and the lower right substrate, and the vertical division according to the type of the discriminated quarter substrate A mounting position correcting step for correcting the position of the quarter substrate with respect to the chuck table so that the position of the planned line and the horizontal division planned line and the position of the clearance groove of the chuck table coincide with each other; In addition, there is provided a method for processing a package substrate comprising at least a dividing step of dividing a quarter substrate into individual package devices.

  Further, in the dividing step, there is provided a package substrate processing method in which the dividing step irradiates a laser beam to the vertical division planned line and the horizontal division planned line to divide the quarter substrate into individual package devices.

  The processing method of the package substrate according to the present invention cuts the center vertical division line and the central horizontal division line of the package substrate and cuts the upper left substrate, the upper right substrate, the lower left substrate, and the lower right substrate into four quarter substrates. A quarter substrate generation step of dividing the substrate into four, and a relief groove is formed corresponding to a plurality of planned vertical division lines and horizontal division planned lines in the divided quarter substrate, and a region defined by the relief grooves A quarter substrate placing step of placing the quarter substrate on a chuck table on which a holding portion for sucking and holding individual package devices is formed, and at least one corner of the quarter substrate. The corner of the quarter substrate placed on the chuck table is imaged by the imaging means for imaging the upper left substrate, the upper right substrate, the lower left substrate, and the lower right substrate from the captured corner state. 4 1/4 A quarter substrate discrimination step for discriminating which of the plates, the position of the vertical division planned line and the horizontal division planned line according to the type of the discriminated quarter board, the clearance groove of the chuck table, A mounting position correcting step for correcting the position of the quarter substrate with respect to the chuck table so that the positions of the chuck table coincide with each other, and a dividing step for dividing the quarter substrate held by the chuck table into individual package devices, By providing a processing method of a package substrate composed at least of the above, it is possible to efficiently divide individual package devices from a large package substrate without requiring a complicated and large chuck table.

  Further, the dividing step according to the present invention is to irradiate the laser beam to the vertical division planned line and the horizontal division planned line and cut the quarter substrate into individual package devices, so that the thermal diffusion substrate is formed of ceramics. Can be cut smoothly, and the productivity is good.

The perspective view of the processing apparatus comprised according to the processing method of this invention. The perspective view of the package board | substrate as a workpiece processed by the processing method of this invention. The principal part perspective view of the package board | substrate cutting device which cuts a package board | substrate with the processing method of this invention. The perspective view of the 1/4 board | substrate produced | generated by the package board | substrate cutting apparatus shown in FIG. The principal part perspective view which shows the implementation state of the 1/4 board | substrate mounting process in the processing method of this invention. The principal part perspective view which shows the implementation state of the 1/4 board | substrate discrimination | determination process in the processing method of this invention. The principal part perspective view which shows the implementation state of the 1/4 board | substrate discrimination | determination process in the processing method of this invention. The figure which shows the state before and behind implementation of the mounting position correction process in the processing method of this invention. The perspective view which shows the correction | amendment means which implements the mounting position correction process in the processing method of this invention. The principal part perspective view which shows the implementation state of the division | segmentation process in the processing method of this invention.

  Hereinafter, a preferred embodiment of a processing method of a package substrate according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a package substrate processing apparatus constructed according to the present invention. A processing apparatus 2 shown in FIG. 1 includes a substantially rectangular apparatus housing. In the processing apparatus 2, a chuck table 3 as a workpiece holding means for holding a workpiece is disposed so as to be movable in a direction (X-axis direction) indicated by an arrow X that is a cutting feed direction. A plurality of suction holding portions 31 are provided on the chuck table 3, and by operating suction means (not shown), it becomes possible to suck and hold a divided quarter substrate 4 described later on the chuck table. It has become. Further, the chuck table 3 includes a rotation mechanism (not shown) and can be rotated by 90 degrees.

  The processing apparatus 2 includes a laser beam irradiation unit 5 that irradiates a workpiece with a laser beam as a processing unit. The laser beam irradiating means 5 includes a casing 51 that can move in the direction indicated by an arrow Y (Y-axis direction) in the figure, and the casing 51 includes a pulse laser beam oscillator that includes a pulse laser beam oscillator and a repetition frequency setting means (not shown). Means are provided. A condenser 52 for condensing the laser beam oscillated from the pulsed laser beam oscillating means is attached to the tip of the casing 51.

  Moreover, the processing apparatus 2 includes an imaging unit 6 for determining the type of a quarter substrate described later. The imaging unit 6 enlarges and captures one of the four corners of the 1/4 substrate enlarged at a low magnification, and transmits the image to a control unit (not shown).

  Further, the processing apparatus 2 includes a correction unit 7 that corrects the mounting position of the quarter substrate, and the correction unit 7 includes a suction plate 71, a pulse motor 72, and a correction arm 73. And the monitor 8 which displays the various information from the control part which is not shown in figure including the image imaged by the above-mentioned imaging means 6 is provided.

FIG. 2 shows a perspective view of a package substrate as a workpiece. The package substrate 20 shown in FIG. 2 has a plurality of ICs, LSIs, and power devices 23 with a predetermined interval to be a grid-like division planned line 22 on the surface of a heat diffusion substrate 21 made of a stainless steel plate having a thickness of 0.3 mm. Is disposed via a bonding agent.
Although not shown in FIG. 2, the synthetic resin is formed on the thermal diffusion substrate 21 so as to fill the outer periphery and the division line 22 for dividing the package substrate 20 into individual power devices 23. It may be coated.

Below, the processing method of the package substrate based on this invention is demonstrated in detail.
In processing the package substrate, a quarter substrate generation process is first performed. The quarter substrate generation step is executed by the package substrate cutting apparatus 9 shown in FIG. 3 provided separately from the processing apparatus 2 shown in FIG. In FIG. 3, only the main part of the package substrate cutting apparatus 9 is shown, and the parts not constituting the main part of the present invention are omitted as appropriate.

  The package substrate cutting apparatus 9 includes at least a holding table 91 as a holding unit that holds the package substrate 20 on the heat diffusion substrate 21 side, and a cutting unit 92 that cuts the workpiece held on the holding table 91. doing. The holding table 91 is formed in a rectangular shape in plan view, and includes a suction chuck support base 911 and a suction chuck 912 mounted on the suction chuck support base 911. The suction chuck 912 is made of breathable porous ceramics, and holds the package substrate 20 on a mounting surface which is the surface of the suction chuck 912 by a suction action by a suction means (not shown). Relief grooves 913 and 914 are provided at positions corresponding to the vertical division line 22 a passing through the center of the substrate 20 and the horizontal division line 22 b passing through the center of the package substrate 20.

  The holding table 91 is configured to be rotated 90 degrees by a rotating mechanism (not shown). The holding table 91 configured in this manner is moved in the machining feed direction indicated by the arrow X in FIG. 3 by a cutting feed means (not shown).

  The cutting means 92 includes a spindle housing 921 arranged substantially horizontally, a rotating spindle 922 rotatably supported by the spindle housing 921, and a cutting blade having a thickness of 200 μm attached to the tip of the rotating spindle 922. 923, and the rotary spindle 922 is rotated by a servo motor (not shown) disposed in the spindle housing 921.

  Hereinafter, a quarter substrate generation process performed using the package substrate cutting apparatus 9 will be described in detail. In the 1/4 substrate generation step, first, the heat diffusion substrate 21 side of the package substrate 20 is placed on a placement surface which is the surface of the suction chuck 912 of the holding table 91 and a suction means (not shown) is operated. The package substrate 20 is sucked and held on the holding table 91. Therefore, the surface of the package substrate 20 held on the holding table 91 is the upper side on which the device 23 is placed. At this time, the vertical division planned line 22a passing through the center of the package substrate 20 is on the escape groove 913 on the suction chuck 912, and the horizontal division planned line 22b passing similarly through the center is on the escape groove 914 on the suction chuck 912. It is arranged to be located.

  An imaging unit (not shown) is provided near the tip of the spindle housing 921, and the holding table 91 holding the package substrate 20 is positioned directly below the imaging unit by a cutting feed unit (not shown). An alignment operation for detecting a machining area to be cut by a control means (not shown) is executed.

  When the alignment for detecting the cutting area of the package substrate 20 held on the holding table 91 is performed as described above, the holding table 91 holding the package board 20 is moved to the cutting work area, and the package board is moved. One end of the 20 vertical division lines 22 a is positioned immediately below the cutting blade 923. Then, while rotating the cutting blade 923, a predetermined amount is cut and fed downward (lowered) from the upper retreat position.

  When the cutting feed is performed in this way, the holding table 91 is moved in the direction of arrow X in FIG. 3 at a predetermined cutting feed speed, and on the package substrate 20 held by the holding table 91 as shown in FIG. When the cutting is performed along the vertical division line 22a passing through the center and the cutting blade 923 reaches the other end of the division line 22a, the movement of the holding table 91 is stopped and the cutting blade 923 is moved to the upper retracted position. Raise up to. As a result, the package substrate 20 is divided along a vertical division planned line 22a passing through the center of the package substrate 20 shown in FIG.

  Next, the holding table 91 is rotated by 90 degrees, and passes through the center of the package substrate 20 held by the holding table 91, and cuts in the same manner as described above along the horizontal division planned line 22b orthogonal to the vertical division planned line 22a. Execute.

  When the above-described cutting process is completed, the package substrate 20 formed with a large size is formed into an upper left substrate 4a, an upper right substrate 4b, a lower left substrate 4c, and a lower right substrate 4d, as shown in FIGS. The quarter substrate generation process is completed. 4A to 4D have substantially the same dimensions in plan view.

  Next, the 1/4 substrate is placed on the chuck table 3 of the package substrate processing apparatus 2 of the present invention shown in FIG. 1, and the steps subsequent to the 1/4 substrate placing step are executed. Hereinafter, the ¼ substrate placement process, the ¼ substrate discrimination process, and the placement position correction process will be described in detail with reference to FIGS.

  The package substrate processing apparatus 2 shown in FIG. 1 has a storage box (not shown) that stores a plurality of quarter substrates 4 created in the previous process, and a transfer arm (not shown). When the 1/4 substrate placement process as shown in FIG. 5 is started, the transfer arm takes out the 1/4 substrate 4 from the storage box and places it on a predetermined position on the chuck table 3 that is uniformly set. It is supposed to be. As described above, the chuck table 3 has a plurality of suction holding portions 31, and each suction holding portion 31 is provided with a suction hole 32, and between each suction holding portion 31, 31. In addition, a relief groove 33 for escaping a laser beam used in a splitting process described later is provided. When the quarter substrate 4 is placed on the chuck table 3, a suction means (not shown) is operated to suck and hold the quarter substrate 4 on the chuck table 3, so that the quarter substrate placement is performed. The placing process ends.

  Here, as is clear from the description of FIGS. 4A to 4D, the ¼ substrates 4 a to 4 d are obtained by dividing the package substrate 20 into four parts, and a plurality of pieces are formed on the upper surface of the thermal diffusion substrate 21. From the relationship of disposing the devices 23, the outer peripheral portion of the region where the plurality of devices 23 are disposed is set to be larger (for example, 10 mm) than the width (for example, 1.2 mm) of the division line between the devices 23. Therefore, although the external dimensions of the quarter substrates 4a to 4d are the same, the distance from the outer peripheral end of each of the quarter substrates 4a to 4d to the device 23 and the distance to each division line are different. Based on the outer peripheral shape of the quarter substrates 4a to 4d, when the substrate is uniformly placed on the chuck table 3, the division set on the quarter substrate depends on which quarter substrate is placed. The positional relationship between the planned line and the relief groove 33 on the chuck table 3 is different, and even if the quarter substrate can be arranged at a certain position, it cannot proceed to the process of dividing into the package devices as they are. Problems arise.

  In order to deal with the above problems, in the present invention, after the quarter substrate placement process is completed, the quarter substrate discrimination process is executed. In the quarter substrate discrimination step, first, the upper left corner of the quarter substrate 4 arranged on the chuck table 3 (FIGS. 6-1 (a), (b), FIGS. 6-2 (c), ( The area indicated by A in d) is imaged by the imaging means 6. The image data (images indicated by A ′ in FIGS. 6-1 (a), (b), FIGS. 6-2 (c), and (d)) captured by the imaging unit 6 are not illustrated. Sent to.

  The image shown in the A ′ area of FIG. 6A is an enlargement of the upper left corner of the quarter substrate, and the outer peripheral edge in the X coordinate axis direction and the upper left corner at the upper left corner of the quarter substrate. The distance from the nearest device 23 in the part is a (= 10 mm), and the distance between the outer peripheral end in the Y coordinate axis direction and the nearest device 23 is also a (= 10 mm). Then, when the image indicated by the A ′ area is transmitted to the control unit, the control unit performs well-known pattern matching based on the transmitted image information of the area A ′ and image information registered in advance. Then, it is determined that the quarter substrate shown in FIG. 6A is the “upper left substrate 4a” shown in FIG.

  Similarly to the above, the image shown by the A ′ area in FIG. 6B is the distance between the outer peripheral end in the Y coordinate axis direction at the upper left corner of the quarter substrate and the nearest device 23 at the upper left. Is a (= 10 mm), and the distance between the outer peripheral end in the X coordinate axis direction and the nearest device 23 is b (= 0.5 mm). Then, when the image shown in the A ′ area is transmitted to the control unit, the image information formed by the outer peripheral end and the nearest device 23 and the well-known image information based on the pre-registered image information Image processing means such as pattern matching determines that the ¼ board shown in FIG. 6B is the “upper right board 4b” shown in FIG. In the cases shown in FIGS. 6-2 (c) and 6-2 (d), the quarter substrate shown in FIGS. 4 (c) and 4 (d) is processed by the same processing as described above. It is determined that they are “lower left substrate 4c” and “lower right substrate 4d”, respectively, and the ¼ substrate determination process is completed. By providing the 1/4 substrate discriminating step, it is possible to determine which pattern of the 1/4 substrate 4 is a 1/4 substrate, regardless of which direction of the 1/4 substrate 4 is placed on the chuck table. it can. In the present embodiment, the numerical values of a and b shown in FIGS. 6-1 and 6-2 have been described as 10 mm and 0.5 mm, respectively, but the numerical values are merely examples. In addition, the widths a and b represented in the drawings are not represented so as to match the actual dimension values for convenience of explanation.

  When the 1/4 substrate discrimination process is completed, it is determined which of the 1/4 substrates 4 mounted on the chuck table 3 is, and the placement position correcting process is executed. The placement position correcting process executed when the quarter substrate 4 placed on the chuck table 3 is the upper left substrate 4a will be described in detail below with reference to FIGS.

  FIG. 7A shows a state where the upper left substrate 4 a is placed on the chuck table 3. In FIG. 7 (a), the outer periphery formed on the package substrate before 1/4 division is uniformly placed by the 1/4 substrate placement step based on the external dimensions of the quarter substrate 4. Due to the presence of the portion, the division line 22 formed by the device 23 is shifted from the escape groove 33 provided in the chuck table 3, and the division step cannot be executed as it is. Here, as described above, since the quarter substrate 4 is determined to be the upper left substrate 4a, the corner portion of the upper left device 23 from the outer peripheral end in the X-axis direction and the Y-axis direction. It is known that the dimensions up to point P are each a.

  The mounting position correcting step is executed using the correcting means 7 shown in FIG. In the upper left part on the chuck table 3, a target point P ′ is set in advance so that all the scheduled division lines can be matched by matching the corner P point of the upper left device 23 on the ¼ substrate. The coordinate point of P ′ on the chuck table 3 in the processing apparatus 2 is stored in the control unit. Then, the correction arm 72 of the correction means 7 is moved back and forth and moved up and down to make the P point of the 1/4 substrate 4a determined in the 1/4 substrate determination step coincide with the coordinates of the target point P ′. The ¼ substrate 4a is sucked by the suction plate 71 by operating upward. The suction plate 71 is configured to be rotatable by a pulse motor 72 driven by a control signal from the control unit, so that the position of the point P matches the target point P ′ and the chuck table 3 And the quarter substrate 4a is placed on the chuck table 3 again, and a suction means (not shown) is provided. It operates and is sucked and held by the sucking and holding part of the chuck table 3, and the mounting position correcting step is completed.

  After the above-described position correction process is completed, the dividing process shown in FIG. 9 is executed. As described above, before entering the dividing step, the coordinates P ′ on the chuck table 3 and the coordinates P of the quarter substrate 4a to be processed are grasped and the positions are adjusted so that the two coordinates coincide. Based on the coordinates, the casing 51 of the laser beam irradiation means 5 is moved back and forth and moved up and down, and the chuck table 3 is operated so that the ¼ substrate is placed directly under the condenser 52 of the laser beam irradiation means 5. Position one end of the planned split line. And the condensing point of the pulse laser beam irradiated from the collector 52 is matched with the surface vicinity of the thermal diffusion board | substrate 21 in a division | segmentation planned line.

  Next, the chuck table 3 is irradiated in a predetermined direction in the direction indicated by the arrow X1 in FIG. Move at machining feed rate. At this time, assist gas injection means (not shown) is provided in the vicinity of the condenser 52, and air is injected at a pressure of 1 Mpa to blow off debris generated by laser processing to the laser processing portion. The debris blown off by the jetting means is pushed into the escape groove 33 of the chuck table 3 and does not come out to the surface.

  When the pulse laser beam reaches the other end of the division line to be irradiated, the irradiation of the pulse laser beam is stopped and the movement of the chuck table 3 is stopped. And if the said laser processing is implemented along all the division | segmentation planned lines formed in the predetermined direction of the thermal diffusion board | substrate 21 mentioned above, the chuck table 3 will be rotated 90 degree | times, The thermal diffusion substrate is divided along the division lines in the direction orthogonal to each other, and the division process is performed along all the division lines formed in the predetermined direction as described above, and the division process is completed. .

  Even when the division is performed along all the division lines, the suction holding portions 31 and the suction holes 32 on the chuck table 3 are provided corresponding to the individual package devices. It is possible to maintain the state of being held by the suction holding unit 31 on the table 3 and being held in the state of a ¼ substrate. If the suction state of the suction holding unit is released, the individual package devices after the division are removed. It can be easily recovered.

In addition, the cutting by the laser beam irradiation means used for the said division | segmentation process is performed on the following process conditions, for example.
Laser beam wavelength: 1 μm
Average output: 150W
Repetition frequency: 18 kHz
Condensing spot diameter: 50 μm
Processing feed rate: 160 mm / sec

  As described above, the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to the above-described embodiment. For example, instead of the laser beam irradiation means used as the processing means in the dividing step, cutting is performed. It is also possible to use a blade cutting means.

2: Processing device 3: Chuck table 4a, 4b, 4c, 4d: 1/4 substrate 5: Laser beam irradiation means 6: Imaging means 7: Correction means 9: Package substrate cutting device 20: Package substrate 21: Thermal diffusion substrate 22a, 22b: Scheduled line 23: Power device 91: Holding table

Claims (2)

A package substrate processing method for dividing a package substrate, in which a plurality of devices are arranged on a surface of a thermal diffusion substrate in a region partitioned by a vertical division line and a horizontal division line, into individual package devices,
A quarter substrate generation step of dividing the center vertical division line and the central horizontal division line of the package substrate into four quarter substrates: an upper left substrate, an upper right substrate, a lower left substrate, and a lower right substrate; ,
Escape grooves are formed corresponding to a plurality of planned vertical division lines and horizontal division planned lines in the divided 1/4 substrate, and individual package devices are sucked and held in each of the regions defined by the escape grooves. A 1/4 substrate placing step of placing the 1/4 substrate on the chuck table on which the holding portion is formed;
The imaging means for imaging at least one corner of the quarter substrate images the corner of the quarter substrate placed on the chuck table, and from the state of the corner thus imaged, the upper left A 1/4 substrate discriminating step for discriminating which of the 4 1/4 substrates of the substrate, the upper right substrate, the lower left substrate, and the lower right substrate;
The position of the 1/4 substrate with respect to the chuck table is set so that the position of the vertical division planned line and the horizontal division planned line corresponding to the determined type of the 1/4 substrate coincide with the position of the escape groove of the chuck table. A mounting position correction process to be corrected;
A dividing step of dividing the quarter substrate held on the chuck table into individual package devices;
A processing method of a package substrate comprising at least   The package substrate processing method according to claim 1, wherein the dividing step divides the quarter substrate into individual package devices by irradiating a laser beam to the vertical division planned line and the horizontal division planned line.