Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B28—WORKING CEMENT, CLAY, OR STONE
  • B28D—WORKING STONE OR STONE-LIKE MATERIALS
  • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
  • B28D5/0058—Accessories specially adapted for use with machines for fine working of gems, jewels, crystals, e.g. of semiconductor material
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P54/00—Cutting or separating of wafers, substrates or parts of devices

Definitions

• the invention relates to the processing of integrated circuit units and in particular the processes involved in cutting the units from substrates of a plurality of said units. Further the invention relates to methods for optimizing the rate of processing of said units.
• Integrated circuit units are generally rectilinear, i.e. having straight sides at right angles to each other.
• the most efficient form of dicing or cutting these units from a substrate is generally using a dicing saw which performs a straight cut very quickly in comparison to other such cutting methods.
• An example includes the use of high pressure water jets or alternatively, lasers in order to effect these cuts.
• An example of a system whereby a dicing saw and a profile cutting means are combined to produce a more efficient system for cutting is disclosed in PCT publication no. WO2007/073356, the contents of which are incorporated herein by reference.
• the aforementioned system is arranged to maximize the speed of processing of the integrated circuit units through the cutting zones as profile cutting devices, whilst useful for profile cutting, are inherently slower than a dicing saw. It is the speed of the profile cutting devices that limits their use and it would, therefore, be useful to have a system whereby the rate of processing using a profile cutting device is increased.
• the invention provides A system for cutting a plurality of substrates of integrated circuit units comprising a plurality of tables, each table including a plurality of trays, each tray arranged to receive one of said substrates; each of said tables selectively movable between a respective loading station for receiving said substrates and a cutting station for cutting the substrates, and; a substrate placement device for placing the substrates on the respective trays of said tables; wherein the substrate placement device is arranged to sequentially place substrates on said tables with said tables arranged to sequentially move to the cutting station after receiving the substrates and then return to their respective loading stations for placement of additional substrates.
• the invention provides A method for cutting a plurality of substrates of integrated circuit units comprising the steps of : Providing at least two selectively movable tables; loading a portion of said plurality of substrates to a first of said tables, each table including a plurality of trays, each tray arranged to receive one of said substrates; moving said first table to a cutting station; cutting said substrates; loading a second of said tables with a further portion of said plurality of substrates; moving said cut substrate from said first table; moving the first table to the first loading station; moving the second table to the cutting station; cutting the substrate on the second table; removing the cut substrate from the second table; moving the second table to the second loading station.
• This system is particularly useful where a profiled cutting device is preferred for all the cutting of an integrated circuit unit.
• the increased speed of combining with a dicing saw cannot be benefited.
• the increase of multiple substrates subject to the cutting not just within the cutting zone but also within the pre-processing of the substrates, therefore, increases the rate of units per hour (UPH) and so improving the rate of processing by a profile cutting device.
• UHP units per hour
• the substrates may be completely cut through.
• the cutting device in this case a laser head, may cut through the integrated circuit units but not completely through the substrates.
• the integrated circuits may be located upon a mould such that whilst the integrated circuit units can be completely cut through, the laser head only partially cuts through the underlying mould.
• the integrated circuit units may remain in contact with the substrate and so remain as a single strip even though the units themselves have been singulated.
• the laser head is capable of cutting a variety of materials including metal, ceramic, plastic, glass and other such materials available for use as integrated circuits or moulds for substrates.
• the device 5 may be adapted for use with a conventional dicing saw device.
• the laser head may be adapted to only perform profile cutting of the substrates and, therefore, the integrated circuit units may not be singulated but only having profile cuts taken, and depth control cutting.
• Such substrates may then be delivered to a dicing saw device for completion of the dicing process.
• FIG. 1 is a plan view of a processing device according to one embodiment of the present invention.
• Figure 2 is a flow chart of a process according to a further embodiment of the present invention.
• Figures 3 A to 3 C are elevation views of substrates having cuts of varying depth.
• Figures 1 and 2 show complementary embodiments of the present invention whereby multiple substrates are delivered to multiple tables for alignment and cutting processes so as to increase the UPH of units through the device.
• FIG. 1 shows such a device according to an embodiment of the present invention.
• the device 5 includes a loading mechanism whereby an onloader 20 collates and racks substrates ready for delivery to the device. The substrates are sequentially moved down the onloader 20 until they reach the onset point where upon a pusher 10 pushes them into engagement with an inlet rail 25.
• the device 5 includes a substrate placement device which in this embodiment includes a frame lifter 35 mounted to a linear rail 36.
• the frame lifter 35 engages the substrate within the inlet rail 25 through a vacuum source and lifts the substrate to one of two trays 37A, B located on a first table 40.
• an alignment inspection device which includes an imaging device, such as a camera, 45 mounted to a second linear rail 46.
• the imaging device 45 can move freely along the rail and so check the substrates for their alignment within the trays and the table.
• the table is movable to a cutting zone whereby substrates mounted to the table are cut using a dual laser head 50.
• the now singlulated units are removed from the table by an off loader picker 70 for eventual offloading.
• the table 55 now empty of units, moves back to the linear rail 30.
• the key aspect of the invention is the ability of the system to have in this embodiment, two tables 40, 55 operating simultaneously. That is, whilst the first table is undergoing cutting, the second table is being loaded with substrates and undergo alignment inspection. When the table undergoing cutting is finished, it moves back to the linear rail so that it can be further loaded with substrates and the next table moves to the cutting zone.
• the units are removed by unit removal device, such as a picker 70 and subsequently moved to a further inspection 75 whereby the units are inspected for defects.
• unit removal device such as a picker 70
• a further inspection 75 whereby the units are inspected for defects.
• inspection occurs at the outlet vision inspection zone 75 from underneath.
• the imaging device 75 moves along a linear rail and this together with movement of the picker 70 along its dedicated rail 80, permits full inspection of all the units held within the picker.
• the inspected units are then delivered to an off loader whereby strips of units are pushed by pusher 85 to an off loading rack 90 for delivery to the customer.
• Figure 2 shows a more detailed process for an embodiment of the present invention.
• the process as detailed in Figure 2 may be applied to a device such as that shown in Figure 1 or to another device falling within the present invention.
• the process begins 100 with loading of a magazine 105.
• the strip is loaded onto an inlet rail 110 which is pushed to the inlet rail.
• the strip is loaded to a first laser table 115 through first loading a strip to a first tray of the laser table using a strip picker and then the same strip picker loading a subsequent strip to the second tray within the first laser table.
• the strips undergo an orientation inspection 120 whereby an imaging device checks from above the strips lying in each of the first and second trays of the first laser table.
• the orientation inspection station is in communication with a control system 125 whereby the signal received from the orientation check is recorded against the respective strip.
• the alignment information may be gained from a variety of inspection protocols including an eight corner check, whereby fiduciary marks for key points on the strip are identified, up to an "all line check" whereby each individual line of units is separately inspected.
• This has the advantage of ensuring alignment to be checked and recorded but suffering from a much longer inspection period. Accordingly the designer of the device will determine whether the greater assurance of alignment of the strip is balanced against the increase in inspection time. It will be noted that for an "all line check", the period of inspection approximates that of the cutting of a substrate by the laser head.
• the calculation of the alignment 130 will use the alignment vision check for each of the trays from the first laser table and calculate:
• the strip picker In parallel but staggered from the processing of the first laser table, when the strip picker is free from loading the first laser table, it will then load strip to the second laser table which has just had singulated units removed from it and returned to a loading position.
• the second laser table follows an identical path to that of the first laser table including an orientation check 155 calculation of the strip alignment 160 and subsequent laser cutting 165 and eventually having the singulated units removed from the second laser table 170.
• the present invention seeks to optimize the UPH for the device by maximizing use of individual functional stations within the device including the strip picker alignment check and laser heads.
• delay in usage of the functional stations is more a function of the varying processing times for each station.
• the strip picker becomes available for loading of strip once the table has been loaded and sent to the alignment check.
• the alignment check can be made available for a subsequent laser table when the present laser table is sent to cutting. It follows this is equally applicable for the laser cutting heads and the off loader picker.
• the tables are capable of carrying two substrates.
• the invention is not limited to merely two substrates per table but could have many substrates and equally each table may be adapted to receive several strips but process only those actually present.
• a laser table may be capable of holding say four strips with the alignment check being used to identify whether each tray within the table is actually being occupied.
• the alignment check can identify this and ensure that the laser heads off loader picker and subsequent stations are informed of the actual number of strips to process.
• the process continues after- engaging the off loader picker whereby the units are taken to a laser cutting check 180 which might be a sampling check, i.e. randomly or selectively choosing units to inspect or a full check of each unit.
• the motor position may then be calculated.
• This information can be sent to a laser cutting check control system 190 which will recall and transmit the vision signal cutting quality and cutting position.
• the units are then off loaded to an off loader magazine 185. In this embodiment the units are off loaded as a strip and then individual lines of units can be pushed to the off loader magazine 195.
• cutting at the cutting station may execute a full cut, and so singulating individual units from the substrate.
• Figures 3 A to 3 C show varying types of partial cuts that may also be possible according to specific embodiments of the present invention.
• the units such as QFN
• the units will involve a very slow process.
• a QFN typical substrate having a copper strip 205 of thickness 0.2 mm, mounted on a plastic mold 200 of thickness 0.7 mm, only full cutting is practical.
• the depth is subject to greater control.
• the present invention permits cutting of the copper 205 only, as shown in Figure 3 A in order to increase sawing speed as following process.
• this system is able to control 0.2mm cutting depth with certain cutting width by multiple cutting of the Beam. This can be extended to cutting the entire copper strip, and partially cut the mold. In this case, the units have been singulated, but are maintained as a strip due to the partial cut of the mold, as shown in Figure 3B.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Dicing (AREA)
• Laser Beam Processing (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

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• 2008
  • 2008-05-02 SG SG200803452-2A patent/SG142402A1/en unknown
• 2009
  • 2009-05-04 JP JP2011507379A patent/JP5420640B2/ja not_active Expired - Fee Related
  • 2009-05-04 WO PCT/SG2009/000158 patent/WO2009134212A1/en not_active Ceased
  • 2009-05-04 KR KR1020107027093A patent/KR20110013440A/ko not_active Withdrawn
  • 2009-05-04 US US12/990,491 patent/US20110036339A1/en not_active Abandoned
  • 2009-05-04 CN CN2009801165598A patent/CN102046344A/zh active Pending

Patent Citations (3)

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