JP6488921B2 - Rework device and rework method - Google Patents

Description

  The technology disclosed in the present application relates to a rework apparatus and a rework method.

  When a chip is broken or defective on a substrate on which the chip is surface-mounted via solder, rework may be performed to replace the chip. In this chip rework, a rework apparatus for heating the chip is used in order to melt the solder so that the chip can be removed from the substrate.

  As such a rework device, for example, the surface temperature of the heating object is detected by sensors arranged in a lattice pattern, and the temperature distribution of the heating object is minimized by locally heating the heating object. The limit is proposed (for example, see Patent Document 1).

JP 2005-85708 A JP 2004-343111 A

  However, even if the part where the temperature of the chip is low is locally heated, if the temperature of the part tends to decrease due to thermal diffusion or the like, the solder cannot be melted at that part, and the chip is accurately removed from the substrate. It may be difficult to remove.

  Then, the technique which this application discloses aims at enabling it to remove a chip | tip accurately from a board | substrate as one side surface.

  In order to achieve the above object, according to one aspect of the technology disclosed in the present application, a rework device including a preheating mechanism, a laser heating light source, and a control unit is provided. The preheating mechanism preheats the chip surface-mounted on the substrate via the solder, and brings the solder close to the melting temperature. The laser heating light source heats each of the plurality of grids to a temperature equal to or higher than the melting temperature of the solder by sequentially irradiating a plurality of grids obtained by virtually dividing the chip after the chips are preheated by the preheating mechanism. To do. The control unit includes a laser heating light source based on the current temperature of each of the plurality of grids after the chip is preheated by the preheating mechanism, and the temperature increase rate and the temperature decrease rate obtained for each of the plurality of grids. To change the order of irradiating a plurality of grids with laser light.

  According to the technology disclosed in the present application, the chip can be accurately removed from the substrate.

It is a front view of a rework apparatus. It is a figure which shows the state which preheats the BGA chip | tip with the preheating mechanism. It is a figure which shows an example of the temperature distribution of the preheated BGA chip | tip and its peripheral part. It is a figure which shows the state which is heating the grid with a laser heating light source. It is a figure explaining a mode that a temperature rise rate and a temperature fall rate are calculated about each of a some grid. It is a figure which shows an example of the result of having calculated the temperature rise rate, the temperature fall rate, the heating time, and the maintenance time about each of several grids. It is a figure which shows an example of the present temperature obtained about each of several grid, a temperature rise rate, and a temperature fall rate. It is a flowchart which shows the flow of operation | movement of a control unit. It is a figure which shows an example of each temperature change of the some grid heated by the rework apparatus.

  Hereinafter, an embodiment of the technology disclosed in the present application will be described.

  As shown in FIG. 1, the rework device 10 according to the present embodiment includes a pair of preliminary heating mechanisms 12, a warm air machine 14, a laser heating light source 16, a thermo camera 18, and a control unit 20.

  In the present embodiment, the heating object of the rework apparatus 10 is a BGA (Ball Grid Array) chip 22. This BGA chip 22 is an example of a “chip”. The BGA chip 22 has a plurality of ball-shaped solders 24. The plurality of solders 24 are arranged in a matrix on the lower surface of the BGA chip 22, and the BGA chips 22 are surface-mounted on the substrate 26 via the plurality of solders 24.

  In addition to the BGA chip 22, a plurality of components 28 are mounted on the surface of the substrate 26. A plurality of components 30 are also mounted on the back surface of the substrate 26. The plurality of components 30 are located on the back side of the BGA chip 22.

  The pair of preheating mechanisms 12 includes a heater 32. The pair of preheating mechanisms 12 and the warm air machine 14 are disposed on the back side of the substrate 26. The warm air fan 14 is disposed on the back side of the BGA chip 22, and the pair of preheating mechanisms 12 are disposed on both sides of the warm air fan 14.

  The laser heating light source 16 is disposed to face the BGA chip 22. Laser light 34 is output from the laser heating light source 16. The thermo camera 18 is an example of a “detector” and detects the surface temperature of the BGA chip 22. The laser heating light source 16 and the thermo camera 18 are communicably connected to the control unit 20 and are controlled by the control unit 20. The control unit 20 is a personal computer, for example, and executes a plurality of processes to be described later.

  Next, a rework method using the above-described rework device 10 will be described.

  FIG. 8 is a flowchart showing the operation flow of the control unit 20. For the step numbers and the contents of each process in the following description, refer to FIG. 8 as appropriate.

  First, as shown in FIG. 2, the control unit 20 operates the heater 32 of the preheating mechanism 12 (step S1). When the heater 32 is activated, the BGA chip 22 is preheated and the solder 24 is brought close to the melting temperature. Moreover, the warm air machine 14 is operated and the heat of the back surface of the substrate 26 is diffused. In step S2 and subsequent steps described below, the operation of the preheating mechanism 12 may be continued to keep the BGA chip 22 warm, or the operation may be stopped.

  Subsequently, the control unit 20 operates the thermo camera 18 and measures the temperature of the BGA chip 22 and its peripheral portion using the thermo camera 18 (step S2). FIG. 3 shows an example of the temperature distribution of the preheated BGA chip 22 and its peripheral part. In FIG. 3, the darker the dots, the higher the temperature. In this example, as indicated by an arrow A, heat is transmitted to components or structures adjacent to the BGA chip 22, thereby causing thermal diffusion in one part 22 A of the BGA chip 22, and the BGA chip 22 and its surroundings. There is variation in the temperature distribution of the part.

  Next, as shown in FIG. 4, the control unit 20 operates the laser heating light source 16 to heat the BGA chip 22. At this time, the control unit 20 virtually divides the BGA chip 22 into a plurality of grids. In the present embodiment, as an example, the BGA chip 22 is divided into a total of nine grids of three vertically and horizontally. 4 and 5, identification numbers “1” to “9” are assigned to the plurality of grids in order to identify the plurality of grids.

  Then, the control unit 20 causes each of the plurality of grids to be heated by sequentially irradiating the plurality of grids with the laser light 34 from the laser heating light source 16 under certain conditions (step S3). At this time, the control unit 20 heats a plurality of grids in ascending order of numbers, for example. Further, the control unit 20 calculates and stores a temperature increase rate and a temperature decrease rate for each of the plurality of grids when the plurality of grids are sequentially irradiated with the laser light 34 from the laser heating light source 16 (step S4).

  As shown in the balloon of FIG. 5, the temperature increase rate is calculated from the temperature increase during laser light irradiation (laser ON) for a certain period of time. On the other hand, the temperature decrease rate is calculated from the temperature decrease while the laser beam irradiation is stopped (laser OFF).

  FIG. 6 shows a list of temperature increase rates and temperature decrease rates obtained for each of the plurality of grids in FIG. The temperature increase rate and the temperature decrease rate of each of the plurality of grids shown in FIG. 6 are used in the subsequent steps S5 to S11. Below, operation | movement of the control unit 20 is demonstrated based on an example of the temperature rise rate and temperature fall rate of each of the some grid shown by FIG.

  In FIG. 6, the heating time is the time required to heat each grid from the lower limit temperature to the upper limit temperature, and the maintenance time is from the state where each grid is heated to the upper limit temperature until it falls to the lower limit temperature. It takes time. In FIG. 6, the heating time is calculated by “(upper limit temperature−lower limit temperature) / temperature increase rate”, and the maintenance time is calculated by “(upper limit temperature−lower limit temperature) / temperature decrease rate”.

  In the present embodiment, the melting temperature of the solder 24 is “220 ° C.”, and the lower limit temperature of each of the plurality of grids heated by the laser heating light source 16 is “220 ° C.” that is the melting temperature of the solder 24. Is set. Further, the upper limit temperature of each of the plurality of grids heated by the laser heating light source 16 is set to “230 ° C.” which is a temperature equal to or higher than the melting temperature of the solder 24. For example, the upper limit temperature is set to a temperature at which it is possible to suppress thermal influence on peripheral components of the BGA chip 22.

  As shown in the list of FIG. 6, in the example of this embodiment, the total heating time for each of the plurality of grids is “29.2 seconds”, and the maintenance time for each of the plurality of grids. The total is “96.6 seconds”. In this way, the heating conditions (laser light output) in the laser heating light source 16 are adjusted so as to secure a maintenance time several times longer than the heating time. This heating condition is used in steps S5 to S11 later.

  FIG. 7 shows an example of the current temperature for each of the plurality of grids together with the temperature increase rate and the temperature decrease rate described above. The current temperature in this case is a temperature after the grid is preheated by the preheating mechanism 12 and then further heated by the laser heating light source 16 for calculation of the temperature increase rate and the temperature decrease rate. The target temperature range in FIG. 7 is not less than “220 ° C.” that is the above-mentioned lower limit temperature and not more than “230 ° C.” that is the upper limit temperature.

  In an example of the present embodiment, the current temperatures of the grids “6”, “8”, and “9” are “225 ° C.” and are within the target temperature range. On the other hand, the current temperatures of the grids “1”, “2”, “3”, “4”, “5”, “7” are “215 ° C.”, “218 ° C.”, “218 ° C.”, “218 ° C.”, respectively. ”,“ 218 ° C. ”and“ 218 ° C. ”, which are outside the target temperature range.

  The control unit 20 executes the following steps S5 to S11 in order to keep the temperature of the grid, which is a temperature outside the target temperature range, within the target temperature range. In FIG. 9, as an example, grids “1”, “2”, “3”, “4”, “5”, and “7”, which are temperatures outside the target temperature range, are according to the following steps S5 to S11. Temperature change is shown. For temperature changes of the plurality of grids “1”, “2”, “3”, “4”, “5”, “7” in the following steps S5 to S11, refer to FIG. 9 as appropriate.

  The control unit 20 extracts the grid having the lowest current temperature among the plurality of grids from the detection result of the thermo camera 18, and heats the grid to the upper limit temperature by the laser heating light source 16 (step S5). The grid with the lowest current temperature among the plurality of grids is the grid “1”, and the grid “1” is heated to the upper limit temperature. The heating time at this time is calculated by “(upper limit temperature−current temperature) / temperature increase rate”. During the calculated heating time, the control unit 20 operates the laser heating light source 16 and grid “1”. Is irradiated with laser light.

  The control unit 20 then heats the remaining grids to the upper limit temperature by the laser heating light source 16 in the descending order of the temperature increase rate during the maintenance time until the grid heated to the upper limit temperature falls from the current temperature to the lower limit temperature. (Steps S6 to S9).

  That is, first, the control unit 20 heats the grid with the highest temperature rise rate among the plurality of remaining grids to the upper limit temperature by the laser heating light source 16 (step S6). From FIG. 7, the grid with the highest temperature rise rate among the plurality of remaining grids is the grid “3”, and this grid “3” is heated to the upper limit temperature here.

  Next, the control unit 20 sets the shortest maintenance time (hereinafter referred to as the shortest maintenance time) among the maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature, and the remaining grid heating time. Compare (step S7). In other words, the shortest maintenance time is the minimum value of the “remaining maintenance time” calculated by “maintenance time at the upper limit temperature−current time” for the grid heated to the upper limit temperature. The remaining grid heating time is calculated by “(upper limit temperature−current temperature) / temperature increase rate”.

  Then, the control unit 20 determines whether or not the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8).

  For example, when 12 seconds have elapsed, the grid heated to the upper limit temperature is grid “1”. The grid “1” reaches the upper limit temperature of 230 ° C. when 10 seconds elapse, and the current temperature of the grid “1” when 12 seconds elapse is “228 ° C.”. The “maintenance time at the upper limit temperature−current time” = “remaining maintenance time” of the grid “1” is “10−2 = 8 seconds”. At this stage, since the grid heated to the upper limit temperature is only the grid “1”, the shortest maintenance time in this case is “8 seconds”.

  On the other hand, the remaining grids are grids “2”, “4”, “5”, and “7”. Since the current temperatures of the grids “2”, “4”, “5”, and “7” are “218 ° C.”, the grids “2”, “4”, and “5” are calculated from the temperature increase rate shown in FIG. The heating times of “7” and “7” are “3.6 seconds”, “5 seconds”, “4 seconds”, and “4 seconds”, respectively.

  Therefore, at this stage, the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than any heating time of the remaining grid. Therefore, the control unit 20 determines that the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8: YES).

  Then, the control unit 20 heats the grid having the highest temperature increase rate among the plurality of remaining grids to the upper limit temperature by the laser heating light source 16 (step S9).

  At this stage, the grids having the highest temperature increase rate among the plurality of remaining grids are the grids “5” and “7”. Here, the small grid “5” is heated to the upper limit temperature. The heating time in step S9 is calculated by “(upper limit temperature−current temperature) / temperature increase rate”. During the calculated heating time, the control unit 20 operates the laser heating light source 16 to emit laser light. The grid “5” is irradiated.

  Then, the control unit 20 determines whether all the temperatures of the plurality of grids are within the target temperature range based on the detection result of the thermo camera 18 (step S10).

  At this stage, grids “2”, “4”, and “7” are left as grids outside the target temperature range. The control unit 20 repeatedly executes step S7 to step 10 until all the temperatures of the grids “1”, “2”, “3”, “4”, “5”, “7” are within the target temperature range. To do.

  Then, the control unit 20 again compares the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature with the remaining grid heating time (step S7). Further, the control unit 20 determines whether or not the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8).

  For example, when 14 seconds have elapsed, the grids heated to the upper limit temperature are grids “1” and “3”. The grid “3” reaches the upper limit temperature of 230 ° C. after 13 seconds. The current temperatures of the grids “1” and “3” when 14 seconds have elapsed are “226 ° C.” and “229.5 ° C.”, respectively. The “maintenance time at the upper limit temperature−current time” = “remaining maintenance time” of the grid “1” is “10−4 = 6 seconds”. In addition, “maintenance time at upper limit temperature−current time” = “remaining maintenance time” of grid “3” is “20−1 = 19 seconds”. Therefore, the shortest maintenance time in this case is “6 seconds”.

  On the other hand, the remaining grids are grids “2”, “4”, and “7”. Since the current temperatures of the grids “2”, “4”, and “7” are “218 ° C.”, the heating time of the grids “2”, “4”, and “7” from the temperature increase rate shown in FIG. Are “3.6 seconds”, “5 seconds”, and “4 seconds”, respectively.

  Therefore, at this stage, the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than any heating time of the remaining grid. Therefore, the control unit 20 determines that the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8: YES).

  Then, the control unit 20 heats the grid having the highest temperature increase rate among the plurality of remaining grids to the upper limit temperature by the laser heating light source 16 (step S9).

  At this stage, the grid having the highest temperature rise rate among the plurality of remaining grids is the grid “7”. Accordingly, the grid “7” is heated to the upper limit temperature.

  Then, the control unit 20 determines whether all the temperatures of the plurality of grids are within the target temperature range based on the detection result of the thermo camera 18 (step S10).

  At this stage, grids “2” and “4” are left as grids outside the target temperature range. Therefore, the control unit 20 returns to step S7 described above to heat the grids “2” and “4” to the upper limit temperature.

  Then, the control unit 20 again compares the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature with the remaining grid heating time (step S7). Further, the control unit 20 determines whether or not the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8).

  For example, after 17 seconds, the grids heated to the upper limit temperature are grids “1”, “3”, “5”, and “7”. The grids “5” and “7” reach the upper limit temperature of 230 ° C. when 15 seconds have elapsed and when 17 seconds have elapsed, respectively. The current temperatures of the grids “1”, “3”, “5”, and “7” when 17 seconds have elapsed are “223 ° C.”, “228 ° C.”, “229 ° C.”, and “230 ° C.”, respectively. “Maintenance time at upper limit temperature−current time” = “remaining maintenance time” of grid “1” is “10−7 = 3 seconds”, and “maintenance time at upper limit temperature of grid“ 3 ” “Current time” = “remaining maintenance time” is “20−4 = 16 seconds”. In addition, “maintenance time at upper limit temperature−current time” = “remaining maintenance time” of grid “5” is “20−2 = 18 seconds”, and “upper limit temperature of grid“ 7 ” “Maintenance time−Current time” = “Remaining maintenance time” is “20−0 = 20 seconds”. Therefore, the shortest maintenance time in this case is “3 seconds”.

  On the other hand, the remaining grids are grids “2” and “4”. Since the current temperatures of the grids “2” and “4” are “218 ° C.”, the heating time of the grids “2” and “4” is “3.6 seconds, respectively, based on the temperature increase rate shown in FIG. ”,“ 5 seconds ”.

  Therefore, at this stage, the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is shorter than the remaining grid heating time. Therefore, the control unit 20 determines that the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is shorter than the remaining grid heating time (step S8: NO).

  Then, the control unit 20 causes the laser heating light source 16 to reheat the grid closest to the lower limit temperature to the upper limit temperature among the grids heated to the upper limit temperature (step S11).

  At this stage, the grid whose current temperature is closest to the lower limit temperature among the grids heated to the upper limit temperature is the grid “1”. Therefore, the grid “1” is reheated to the upper limit temperature. The heating time in this step S11 is calculated by “(upper limit temperature−current temperature) / temperature increase rate”. During the calculated heating time, the control unit 20 operates the laser heating light source 16 and the grid “ 1 "is irradiated with a laser beam. After step S11, the control unit 20 returns to the above-described step S7 in order to heat the above-mentioned grids “2” and “4” to the upper limit temperature again.

  Then, the control unit 20 again compares the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature with the remaining grid heating time (step S7). Further, the control unit 20 determines whether or not the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8).

  For example, when 22 seconds have elapsed, the grids heated to the upper limit temperature are grids “1”, “3”, “5”, and “7”. The grid “1” is reheated and reaches the upper limit temperature of 230 ° C. after 22 seconds. The current temperatures of the grids “1”, “3”, “5”, and “7” when 22 seconds have elapsed are “230 ° C.”, “225.5 ° C.”, “226.5 ° C.”, and “227.5”, respectively. ° C ". “Maintenance time at upper limit temperature−current time” = “remaining maintenance time” of grid “1” is “10−0 = 10 seconds”, and “maintenance time at upper limit temperature of grid“ 3 ” “Current time” = “remaining maintenance time” is “20−9 = 11 seconds”. In addition, “maintenance time at upper limit temperature−current time” = “remaining maintenance time” of grid “5” is “20−7 = 13 seconds”, and “upper limit temperature of grid“ 7 ” “Maintenance time−Current time” = “Remaining maintenance time” is “20−5 = 15 seconds”. Therefore, the shortest maintenance time in this case is “10 seconds”.

  On the other hand, the remaining grids are grids “2” and “4”. Since the current temperatures of the grids “2” and “4” are “218 ° C.”, the heating time of the grids “2” and “4” is “3.6 seconds, respectively, based on the temperature increase rate shown in FIG. ”,“ 5 seconds ”.

  Therefore, at this stage, the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than any heating time of the remaining grid. Therefore, the control unit 20 determines that the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8: YES).

  Then, the control unit 20 heats the grid having the highest temperature increase rate among the plurality of remaining grids to the upper limit temperature by the laser heating light source 16 (step S9).

  At this stage, the grid having the highest temperature rise rate among the plurality of remaining grids is the grid “2”. Therefore, the grid “2” is heated to the upper limit temperature. The grid “2” reaches the upper limit temperature of 230 ° C. after 26 seconds.

  Then, the control unit 20 determines whether all the temperatures of the plurality of grids are within the target temperature range based on the detection result of the thermo camera 18 (step S10).

  At this stage, the grid “4” is left as a grid outside the target temperature range. Therefore, the control unit 20 returns to step S7 described above to heat the grid “4” to the upper limit temperature.

  Then, the control unit 20 again compares the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature with the remaining grid heating time (step S7). Further, the control unit 20 determines whether or not the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8).

  For example, when 25 seconds have elapsed, the grids heated to the upper limit temperature are grids “1”, “3”, “5”, and “7”. The current temperatures of the grids “1”, “3”, “5”, and “7” when 25 seconds have elapsed are “227 ° C.”, “224 ° C.”, “225 ° C.”, and “226 ° C.”, respectively. “Maintenance time at upper limit temperature−current time” = “remaining maintenance time” of grid “1” is “10−3 = 7 seconds”, and “maintenance time at upper limit temperature of grid“ 3 ” “Current time” = “remaining maintenance time” is “20−12 = 8 seconds”. In addition, “maintenance time at upper limit temperature−current time” = “remaining maintenance time” of grid “5” is “20−10 = 10 seconds”, and “upper limit temperature of grid“ 7 ” “Maintenance time−Current time” = “Remaining maintenance time” is “20−8 = 12 seconds”. Therefore, the shortest maintenance time in this case is “7 seconds”.

  On the other hand, the remaining grid is the grid “4”. Since the current temperature of the grid “4” is “218 ° C.”, the heating time of the grid “4” is “5 seconds” from the temperature increase rate shown in FIG.

  Therefore, at this stage, the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time. Therefore, the control unit 20 determines that the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is longer than the remaining grid heating time (step S8: YES).

  Then, the control unit 20 heats the grid having the highest temperature increase rate among the plurality of remaining grids to the upper limit temperature by the laser heating light source 16 (step S9).

  At this stage, the grid having the highest temperature rise rate among the plurality of remaining grids is the grid “4”. Therefore, the grid “4” is heated to the upper limit temperature. The grid “4” reaches the upper limit temperature of 230 ° C. after 30 seconds.

  As described above, in the present embodiment, the laser light 34 is irradiated to the plurality of grids based on the current temperature of each of the plurality of grids and the temperature increase rate and the temperature decrease rate obtained for each of the plurality of grids. The order is changed.

  Then, the control unit 20 determines whether all the temperatures of the plurality of grids are within the target temperature range based on the detection result of the thermo camera 18 (step S10).

  For example, when 34 seconds have elapsed, all of the grids “1”, “2”, “3”, “4”, “5”, and “7” are within the target temperature range. In this case, the control unit 20 determines that all the grids are within the target temperature range (step S10: YES). When the control unit 20 determines that all the grids are within the target temperature range, the control unit 20 stops the heating by the laser heating light source 16 and ends the series of processes. Although not particularly illustrated, the grids “6”, “8”, and “9” are within the target temperature range after about 34 seconds.

  As described above, all the grids “1” to “9” are within the target temperature range, and the solder 24 is melted in each of the plurality of grids, so that the BGA chip 22 can be removed from the substrate 26. It becomes a state. The BGA chip 22 is automatically removed from the substrate 26 by, for example, a robot hand, or is removed from the substrate 26 by a manual operation by an operator.

  Next, the operation and effect of this embodiment will be described.

  As described in detail above, in steps S5 to S9 of the present embodiment, a plurality of grids based on the current temperature of each of the plurality of grids and the temperature increase rate and temperature decrease rate obtained for each of the plurality of grids. The order in which the grid is irradiated with the laser light is changed. Therefore, the temperature of multiple grids can be accurately kept within the target temperature range compared to the case where the order of heating is determined based on the current temperature alone because the temperature change is predicted based on the temperature increase rate and the temperature decrease rate. Can do. Thereby, even when thermal diffusion occurs in one portion 22A of the BGA chip 22, the solder 24 of each grid can be brought into a molten state by keeping the temperature of the plurality of grids within the target temperature range. 26 can be accurately removed.

  In step S5 of the present embodiment, the grid having the lowest current temperature among the plurality of grids is first heated to the upper limit temperature. Accordingly, the remaining grid (the grid whose current temperature is higher than the previous grid) can be sequentially heated to the upper limit temperature during the maintenance time until the grid previously heated to the upper limit temperature falls to the lower limit temperature. it can. Thereby, the temperature of a some grid can be efficiently stored in the target temperature range.

  Further, in steps S7 to S9 of the present embodiment, the remaining grids are sequentially heated to the upper limit temperature during the maintenance time until the grid heated to the upper limit temperature falls to the lower limit temperature. At this time, the remaining grid is heated in descending order of the temperature increase rate. For this reason, as many grids as possible can be heated to the upper limit temperature during the maintenance time until the grid heated to the upper limit temperature falls to the lower limit temperature. Therefore, the efficiency at the time of keeping the temperature of the plurality of grids within the target temperature range can be improved.

  Further, in steps S8 and S11 of the present embodiment, when the shortest maintenance time from the current temperature to the lower limit temperature in the grid heated to the upper limit temperature is shorter than the remaining grid heating time, the current temperature is set to the lower limit. The grid closest to the temperature is reheated to the upper limit temperature. Thereby, since it can suppress that the grid heated to the upper limit temperature falls below lower limit temperature, the efficiency at the time of keeping the temperature of a some grid in a target temperature range can be improved also by this. .

  In steps S5, S9, and S11 of this embodiment, the heating time by the laser heating light source 16 is set for each of the plurality of grids based on the current temperature and the temperature increase rate. Accordingly, since the heating time can be set accurately, each grid can be appropriately heated to the upper limit temperature.

  Next, a modification of this embodiment will be described.

  In the above embodiment, the heating object of the rework device 10 is the BGA chip 22, but a chip surface-mounted on the substrate 26 via the solder 24 other than the BGA chip 22 may be the heating object. good.

  In the above embodiment, since the current temperatures of the grids “6”, “8”, and “9” are within the target temperature range, the remaining grids other than the grids “6”, “8”, and “9” are excluded. Are sequentially heated in step S5 to step S11. However, for example, when the current temperatures of the grids “6”, “8”, and “9” are outside the target temperature range, all of the plurality of grids “1” to “9” are included in steps S5 to S11. It may be heated. Further, the number of grids heated in step S5 to step S11 may be any number among the plurality of grids.

  Further, in the above embodiment, the BGA chip 22 is divided into a total of nine grids of three each in the vertical and horizontal directions, but any number of grids may be divided.

  In steps S5, S9, and S11 of the above embodiment, the heating time is set for each of the plurality of grids based on the current temperature and the temperature increase rate. During the set heating time, the control unit 20 operates the laser heating light source 16 to irradiate the grid with laser light. However, the control unit 20 may operate the laser heating light source 16 until it is detected using the thermo camera 18 that the grid is heated to the upper limit temperature.

  In the above embodiment, the thermo camera 18 is used as an example of the “detector”. However, in addition to the thermo camera 18, a detector that detects the temperature of each of the plurality of grids may be used.

  Moreover, in the said embodiment, whenever the process shown with the flowchart of FIG. 8 is performed, the temperature rise rate and temperature fall rate are calculated and memorize | stored about each of a some grid. However, the temperature increase rate and the temperature decrease rate for each of the plurality of grids may be stored in the control unit 20 in advance. And in the process shown by the flowchart of FIG. 8, the process of step S3-S4 may be omitted.

  When the type of the BGA chip 22 is different for each substrate 26, the temperature increase rate and the temperature decrease rate for each of the plurality of grids are stored in the control unit 20 in advance for each type of the BGA chip 22. Also good. Similarly, in the process shown in the flowchart of FIG. 8, the processes in steps S3 to S4 may be omitted.

  In the process shown in the flowchart of FIG. 8, when the processes of steps S <b> 3 to S <b> 4 are omitted, the current temperature of the grid described above corresponds to the temperature after the grid is preheated by the preheating mechanism 12.

  Moreover, the modification which can be combined among said several modifications may be combined suitably.

  As mentioned above, although one embodiment of the technique disclosed in the present application has been described, the technique disclosed in the present application is not limited to the above, and various modifications may be made without departing from the spirit of the present invention. Of course, it is possible.

  In addition, the following additional remark is disclosed regarding one Embodiment of the technique which the above-mentioned this application discloses.

(Appendix 1)
A preheating mechanism for preheating a chip surface-mounted on a substrate via solder and bringing the solder close to a melting temperature;
After the chip is preheated by the preheating mechanism, a plurality of grids obtained by virtually dividing the chip are sequentially irradiated with laser light to heat each of the plurality of grids to a temperature equal to or higher than the melting temperature of the solder. A laser heating light source,
The laser heating based on the current temperature of each of the plurality of grids after the chip is preheated by the preheating mechanism and the temperature increase rate and temperature decrease rate obtained for each of the plurality of grids. A control unit for changing the order of irradiating the plurality of grids with laser light from a light source;
A rework device comprising:
(Appendix 2)
The control unit heats the grid having the lowest current temperature among the plurality of grids to an upper limit temperature higher than the melting temperature of the solder by the laser heating light source after the chips are preheated by the preheating mechanism. The remaining grids among the plurality of grids during the maintaining time until the grid heated to the upper limit temperature among the plurality of grids falls to the lower limit temperature that is the melting temperature of the solder Heating to the upper limit temperature by the laser heating light source in descending order of
The rework device according to appendix 1.
(Appendix 3)
The control unit calculates a maintaining time until the grid is heated to the upper limit temperature among the plurality of grids until the grid is lowered to the lower limit temperature based on a current temperature and the temperature decrease rate, and among the plurality of grids Calculate the heating time until the temperature rises to the upper limit temperature based on the current temperature and the temperature increase rate for the remaining grid, and when the shortest shortest maintenance time among the maintenance times is longer than the heating time, Heating the grid having the highest temperature increase rate among the remaining grids to the upper limit temperature by the laser heating light source;
The rework device according to appendix 2.
(Appendix 4)
The control unit calculates a maintaining time until the grid is heated to the upper limit temperature among the plurality of grids until the grid is lowered to the lower limit temperature based on a current temperature and the temperature decrease rate, and among the plurality of grids Calculate the heating time until the temperature rises to the upper limit temperature based on the current temperature and the temperature increase rate for the remaining grid, and when the shortest shortest maintenance time among the maintenance times is shorter than the heating time, Reheating the grid whose current temperature is closest to the lower limit temperature among the grid heated to the upper limit temperature to the upper limit temperature by the laser heating light source,
The rework device according to appendix 2 or appendix 3.
(Appendix 5)
The control unit sets a heating time by the laser heating light source based on the current temperature and the temperature increase rate for each of the plurality of grids.
The rework device according to any one of appendix 1 to appendix 4.
(Appendix 6)
The control unit stops heating by the laser heating light source when the temperature of the plurality of grids heated to the upper limit temperature falls within a target temperature range between the upper limit temperature and the lower limit temperature. ,
The rework device according to any one of appendix 1 to appendix 5.
(Appendix 7)
A detector for detecting the temperature of each of the plurality of grids;
The control unit sequentially irradiates the plurality of grids preheated by the preheating mechanism with laser light from the laser heating light source, and calculates the temperature increase rate from the detection result of the detector for each of the plurality of grids. calculate,
The rework device according to any one of supplementary notes 1 to 6.
(Appendix 8)
A detector for detecting the temperature of each of the plurality of grids;
The control unit sequentially irradiates the plurality of grids preheated by the preheating mechanism with laser light from the laser heating light source, and calculates the temperature decrease rate from the detection result of the detector for each of the plurality of grids. calculate,
The rework device according to any one of appendix 1 to appendix 7.
(Appendix 9)
Preheating the chip surface-mounted on the substrate via solder by a preheating mechanism, bringing the solder close to the melting temperature,
Based on the current temperature of each of the plurality of grids obtained by virtually dividing the chip and the temperature increase rate and the temperature decrease rate obtained for each of the plurality of grids, a laser is emitted from the laser heating light source to the plurality of grids. The order of irradiating light is changed, and the plurality of grids are sequentially irradiated with laser light from the laser heating light source to heat each of the plurality of grids to a temperature equal to or higher than the melting temperature of the solder.
Rework method including that.
(Appendix 10)
After preheating the chip by the preheating mechanism, the grid having the lowest current temperature among the plurality of grids is heated by the laser heating light source to an upper limit temperature higher than the melting temperature of the solder, Among the plurality of grids, the remaining grids are heated in the descending order of the temperature increase rate during the maintenance time until the grid heated to the upper limit temperature falls to the lower limit temperature which is the melting temperature of the solder. Heating to the upper limit temperature by a light source;
The rework method according to appendix 9, including the above.
(Appendix 11)
Regarding the grid heated to the upper limit temperature among the plurality of grids, the maintenance time until the temperature falls to the lower limit temperature is calculated based on the current temperature and the temperature decrease rate, and the remaining grid among the plurality of grids Based on the current temperature and the rate of temperature increase, the heating time until the temperature rises to the upper limit temperature is calculated.If the shortest shortest maintenance time is longer than the heating time among the maintenance times, the remaining grid Heat the grid having the highest temperature rise rate to the upper limit temperature by the laser heating light source,
The rework method according to appendix 10, including
(Appendix 12)
Regarding the grid heated to the upper limit temperature among the plurality of grids, the maintenance time until the temperature falls to the lower limit temperature is calculated based on the current temperature and the temperature decrease rate, and the remaining grid among the plurality of grids The heating time until the temperature rises to the upper limit temperature is calculated based on the current temperature and the temperature rise rate. If the shortest shortest maintenance time is shorter than the heating time, the heating time is increased to the upper limit temperature. Further, the grid whose current temperature is closest to the lower limit temperature among the grids is reheated to the upper limit temperature by the laser heating light source,
The rework method according to Supplementary Note 10 or Supplementary Note 11, including the above.
(Appendix 13)
For each of the plurality of grids, a heating time by the laser heating light source is set based on the current temperature and the temperature increase rate.
The rework method as described in any one of appendix 9-appendix 12 including this.
(Appendix 14)
When the temperature of the plurality of grids heated to the upper limit temperature falls within a target temperature range between the upper limit temperature and the lower limit temperature, heating by the laser heating light source is stopped.
The rework method according to any one of Supplementary Note 9 to Supplementary Note 13, including:
(Appendix 15)
The temperature of each of the plurality of grids is detected by a detector, and the plurality of grids preheated by the preheating mechanism are sequentially irradiated with laser light from the laser heating light source, and each of the plurality of grids is Calculating the temperature increase rate from the detection result of the detector;
The rework method as described in any one of appendix 9-appendix 14 including this.
(Appendix 16)
The temperature of each of the plurality of grids is detected by a detector, and the plurality of grids preheated by the preheating mechanism are sequentially irradiated with laser light from the laser heating light source, and each of the plurality of grids is Calculating the temperature decrease rate from the detection result of the detector;
The rework method according to any one of Supplementary Note 9 to Supplementary Note 15, including:
(Appendix 17)
When the temperature of the plurality of grids heated to the upper limit temperature falls within a target temperature range between the upper limit temperature and the lower limit temperature, and the solder is in a molten state in each of the plurality of grids. Stop the irradiation of laser light to the plurality of grids, and remove the chip from the substrate,
The rework method according to any one of Supplementary Note 9 to Supplementary Note 16, including:

DESCRIPTION OF SYMBOLS 10 Rework apparatus 12 Preheating mechanism 14 Hot air machine 16 Laser heating light source 18 Thermo camera (an example of a detector)
20 Control unit 22 BGA chip (an example of a chip)
24 Solder 26 Substrate 34 Laser light

Claims (6)

A preheating mechanism for preheating a chip surface-mounted on a substrate via solder and bringing the solder close to a melting temperature;
After the chip is preheated by the preheating mechanism, a plurality of grids obtained by virtually dividing the chip are sequentially irradiated with laser light to heat each of the plurality of grids to a temperature equal to or higher than the melting temperature of the solder. A laser heating light source,
The laser heating based on the current temperature of each of the plurality of grids after the chip is preheated by the preheating mechanism and the temperature increase rate and temperature decrease rate obtained for each of the plurality of grids. A control unit for changing the order of irradiating the plurality of grids with laser light from a light source;
A rework device comprising: The control unit heats the grid having the lowest current temperature among the plurality of grids to an upper limit temperature higher than the melting temperature of the solder by the laser heating light source after the chips are preheated by the preheating mechanism. The remaining grids among the plurality of grids during the maintaining time until the grid heated to the upper limit temperature among the plurality of grids falls to the lower limit temperature that is the melting temperature of the solder Heating to the upper limit temperature by the laser heating light source in descending order of
The rework apparatus according to claim 1. The control unit calculates a maintaining time until the grid is heated to the upper limit temperature among the plurality of grids until the grid is lowered to the lower limit temperature based on a current temperature and the temperature decrease rate, and among the plurality of grids Calculate the heating time until the temperature rises to the upper limit temperature based on the current temperature and the temperature increase rate for the remaining grid, and when the shortest shortest maintenance time among the maintenance times is longer than the heating time, Heating the grid having the highest temperature increase rate among the remaining grids to the upper limit temperature by the laser heating light source;
The rework apparatus according to claim 2. The control unit calculates a maintaining time until the grid is heated to the upper limit temperature among the plurality of grids until the grid is lowered to the lower limit temperature based on a current temperature and the temperature decrease rate, and among the plurality of grids Calculate the heating time until the temperature rises to the upper limit temperature based on the current temperature and the temperature increase rate for the remaining grid, and when the shortest shortest maintenance time among the maintenance times is shorter than the heating time, Reheating the grid whose current temperature is closest to the lower limit temperature among the grid heated to the upper limit temperature to the upper limit temperature by the laser heating light source,
The rework apparatus according to claim 2 or claim 3. The control unit sets a heating time by the laser heating light source based on the current temperature and the temperature increase rate for each of the plurality of grids.
The rework apparatus as described in any one of Claims 1-4. Preheating the chip surface-mounted on the substrate via solder by a preheating mechanism, bringing the solder close to the melting temperature,
Based on the current temperature of each of the plurality of grids obtained by virtually dividing the chip and the temperature increase rate and the temperature decrease rate obtained for each of the plurality of grids, a laser is emitted from the laser heating light source to the plurality of grids. The order of irradiating light is changed, and the plurality of grids are sequentially irradiated with laser light from the laser heating light source to heat each of the plurality of grids to a temperature equal to or higher than the melting temperature of the solder.
Rework method including that.

Images