JP5906527B2 - Mold and resin molding apparatus provided with the same - Google Patents

Description

  The present invention relates to a mold and a resin mold apparatus using the mold.

  For example, in a transfer mold apparatus, a temperature control mechanism for a mold having a cavity is provided, and from the start of filling a mold resin into the cavity from the pot to the resin curing, and further, from the removal of the package part from the mold. A technique for controlling the temperature so that the mold can be performed under an optimum temperature condition has been proposed.

  Specifically, the lower mold supported by the platen of the mold is divided into a plurality of blocks in which cavities, runners, pots and the like are formed, and heaters are arranged between and on the divided blocks. Yes. In addition, sub-heaters and cooling tubes are alternately arranged in the horizontal direction in the vicinity of the cavity in each of the divided blocks. The block is provided with a temperature sensor so that detected temperature information is transmitted to the temperature control unit. The temperature control unit controls the heating operation or cooling operation of the heater, the sub heater, and the cooling tube based on the temperature information (see Patent Document 1).

JP 63-126714 A

However, when controlling the temperature of the mold, the most important is the temperature of the mold surface that touches the molded product, not the heat capacity of the entire mold. When performing transfer molding, since the mold resin flows, the flow rate of the mold resin is high near the gate and the mold surface temperature is difficult to rise, whereas the flow rate of the mold resin after flowing into the cavity is slow, The mold surface temperature is likely to rise. Therefore, the temperature distribution of the mold surface temperature tends to vary.
Especially when molding thin package parts, if the temperature control is not finely controlled, the bonding reliability between the semiconductor chip and the connection terminal may be lowered, and the temperature range and timing for heat-curing the mold resin are not appropriate. There is a risk of quality degradation. Moreover, since the heater is arrange | positioned between the divided blocks and the side like patent document 1, the whole divided block is heated. Thus, when temperature control is performed by heating the entire mold, it is impossible to manage the mold surface temperature in detail. Further, if the sub-heater and the cooling tube are arranged in the same row with respect to the molded product, it is difficult to control the temperature of the mold surface quickly and within a predetermined temperature range.

  The present invention solves the above-mentioned problems of the prior art, a mold mold capable of finely adjusting the mold surface temperature and adjusting it within a predetermined temperature range, and a resin mold having the mold mold and improved in molding quality. To provide an apparatus.

In order to achieve the above object, the present invention comprises the following arrangement.
That is, an upper mold base and a lower mold base each provided with a first heating device and a first temperature sensor, an upper mold chase supported by the upper mold base, and a lower mold chase supported by the lower mold base An upper mold insert and a lower mold insert that are supported by the upper mold chase and the lower mold chase so as to be insertable / removable, and at least one of which is formed with a cavity recess, and the upper chase, the lower mold chase, and the upper mold chase At least one of the mold insert and the lower mold insert is provided with a cooling device and a second heating device in this order from the side close to the cavity recess, and a second temperature sensor is provided in the vicinity of the cavity recess. It is characterized by .

  If the mold is used, the cooling device and the second die are inserted into the at least one of the upper mold insert and the lower mold insert from the side close to the cavity recess, based on the temperature information detected by the temperature sensor provided in the vicinity of the cavity recess. By operating the second heating device or the cooling device provided with the heating devices in this order, the mold surface temperature of the upper die or the lower die or both can be adjusted to a desired temperature range.

  Moreover, in this invention, it is preferable to adjust and maintain the surface temperature of the said mold clamping surface in a desired temperature range by carrying out on-off control of the said cooling device and a 2nd heating apparatus. Thus, the mold surface temperature can be finely adjusted as compared with the case where the mold surface temperature is adjusted by heating the entire mold.

  Further, in the present invention, the cooling pipe through which the refrigerant of the cooling device circulates is piped so as to flow from the front side of the mold, to make a U-turn at the back side in the longitudinal direction of the mold and to flow out from the front side. preferable. Thereby, the assembly and maintenance of the cooling device can be performed on the front side of the upper mold and the lower mold insert, so that workability is good.

  Further, the resin mold apparatus includes any one of the molds described above. This improves the molding quality of the molded product.

  If the mold is used, the mold surface temperature can be finely adjusted within a predetermined temperature range, and if a resin mold apparatus equipped with the mold is used, the molding quality can be improved.

It is sectional drawing of the mold metal mold | die with which resin was supplied in the state opened. It is sectional drawing of the mold metal mold | die in which the pressure reduction space was formed by performing mold closing operation. It is sectional drawing of the mold metal mold | die which the mold closing operation was completed. It is sectional drawing of the mold metal mold | die with which resin filling operation was completed. It is a plane perspective view of a lower mold. It is a graph which shows an example of temperature control of metal mold | die surface temperature.

  Hereinafter, preferred embodiments of a mold and a resin molding apparatus according to the present invention will be described in detail with reference to the accompanying drawings. First, a schematic configuration of the resin mold apparatus will be described. The workpiece W and the mold resin, which are to-be-molded products, are supplied to the mold mold opened and clamped by closing the mold. Then, resin mold is performed by pressure-feeding the mold resin melted by the transfer mechanism to the cavity. The mold clamping mechanism uses a known electric motor as a drive source and moves the movable mold up and down by a link mechanism such as a toggle link. The transfer mechanism is configured to fill the cavity with mold resin by moving the plunger inserted into the pot up and down by a drive source.

  In FIG. 1, a schematic configuration of an upper mold 2 and a lower mold 3 constituting the mold 1 will be described. In the following description, the upper mold 2 is described as a fixed mold, and the lower mold 3 that moves toward and away from the upper mold 2 is described as a movable mold. As an example of the workpiece W, a workpiece in which a plurality of semiconductor chips are flip-chip connected to a wiring board is used.

  An upper chase 5 is assembled to an upper mold base 4 provided in the upper mold 2. An upper mold center insert 6 is assembled to the upper mold chase 5 at a position facing a pot described later, and upper mold inserts 7 are assembled to both sides of the upper mold center insert 6.

  In the upper mold base 4, a first heating device (base heater) 4 a and a first temperature sensor 4 b (first temperature adjustment unit) are installed in close proximity to each other at a plurality of locations. Further, a sealing material 8 (O-ring or the like) is provided on the outer peripheral edge portion on the clamp surface side of the upper mold base 4. The clamp surface of the upper mold insert 7 is provided with a suction hole communicating with a suction device (not shown), and the workpiece W is sucked and held. The upper chase 5 is provided with a vacuum suction path (not shown). The vacuum suction path is connected to a decompression mechanism having a vacuum pump for degassing from a closed space formed in the mold 1 closed with the mold.

  A lower chase 10 is assembled to a lower mold base 9 provided in the lower mold 3. A lower mold insert 11 is assembled to the lower mold chase 10. A pot insert (lower mold center insert) 12 is assembled at a position facing the upper mold center insert 6 of the lower mold 3 (see FIG. 5). A cylindrical pot 12 a is assembled to the pot insert 12. Further, a plunger 13 supported by a known transfer mechanism is inserted into the pot 12a so as to be movable up and down. The lower mold insert 11 is disposed on both sides of the pot insert 12 (see FIG. 5).

  In the lower mold base 9, a first heating device (base heater) 9a and a first temperature sensor 9b (first temperature adjusting unit) are provided close to each other at a plurality of locations. On the clamping surface of the lower mold insert 11, a runner gate 11a and a cavity recess 11b are formed. A second temperature sensor 11c is built in the vicinity of the cavity recess 11b. Also, on both sides of the pot 12a, resin passages 12b continuous with the runner gate 11a are formed at the clamp surface side end of the pot 12a.

  A cooling device 14 (cooling pipe) and a second heating device 15 (second temperature adjustment unit) are provided in a plurality of locations in series in the height direction in this order from the side close to the cavity recess 11b of the lower die chase 10. . The cooling device 14 and the heating device 15 are not necessarily in series in the height direction, but when they are in series, the mold surface temperature can be finely adjusted with good balance. That is, the cooling device 14 and the second heating device 15 each have a temperature gradient around the center during heating and cooling, but at this time, they are arranged at positions that are not in series (in other words, shifted positions). If this is the case, the temperature gradient in the mold cannot be controlled symmetrically, and the temperature may become uneven on the surface of the cavity recess 11b. For example, the temperature is low at the upper position of the cooling device 14 and the temperature is higher at the upper position of the second heating device 15. However, the temperature gradient may be made uniform by arranging the cooling device 14 and the second heating device 15 so as to be shifted by a half cycle of the temperature gradient. For example, the heating by the second heating device 15 disposed between them due to the symmetrical temperature gradient formed by the adjacent cooling devices 14 can be transferred to the surface of the cavity recess 11b in contrast. The cooling device 14 and the second heating device 15 may be provided in the lower mold insert 11 when the thickness of the lower mold insert 11 is sufficient.

  As will be described later, the cooling device 14 and the second heating device 15 can be adjusted to maintain the temperature of the mold clamping surface within a desired temperature range by controlling the temperature by on / off control. Thereby, the mold surface temperature can be finely adjusted as compared with the case where the mold temperature is adjusted by adjusting the output of the heating device for heating the entire mold.

  In FIG. 5, the cooling device 14 provided in the lower mold 3 has a cooling pipe 14a through which the refrigerant circulates from the front side of the lower mold chase 10 and penetrates the lower mold chase 10 in the lower mold longitudinal direction. It is piped so that it makes a U-turn at the back side of the base 9 and returns to the near side again to flow out. As a result, the assembly and maintenance of the cooling device 14 can be performed on the front side of the lower die chase 10, so that workability is good. In addition, the effect is particularly high in a configuration in which access to the back surface of the press is difficult, such as a modular mold apparatus in which a plurality of presses are arranged.

  In addition, a refrigerant | coolant may be made to flow in from the pot insert 12 side, and may be made to flow in from the reverse. In this case, the cavity recess 11b can be evenly cooled by using the temperature difference between the return and return of the refrigerant by flowing from the higher temperature side (for example, the pot insert 12 side). In addition, by cooling the pot insert 12 side with a low-temperature refrigerant, the resin remaining in the pot 12a after resin filling and the resin in the upper part (cal) can be quickly cooled, and the molding cycle time is shortened. be able to. The cooling device 14 may adopt a configuration in which the refrigerant is not returned into the lower mold chase 10.

Next, the resin molding operation of the resin molding apparatus will be described with reference to FIGS.
In FIG. 1, when the mold 1 is in the mold open state, the workpiece W and the mold resin are carried in by a conveying device (not shown). Specifically, the workpiece W is sucked and held by the upper mold insert 7 of the upper mold 2 so that the semiconductor chip faces downward, the resin tablet 16a is loaded in the pot 12a of the lower mold insert 11, and the granule resin is loaded in the cavity recess 11b. 16b (which may be powder resin, liquid resin, etc.) is supplied. In addition, in the product with high resin filling property, it is not always necessary to supply the resin to the pot 12a and the cavity recess 11b, and only one of them may be used.

  Next, the lower mold 3 is raised by operating the mold clamping mechanism while operating the pressure reducing mechanism provided in the upper mold 2. As shown in FIG. 2, when the sealing material 8 provided on the clamp surface of the upper mold base 4 comes into contact with the clamp surface of the lower mold base 9, a closed space is formed in the mold 1 and pressure reduction proceeds. Further, the resin supplied to the pot 12a and the cavity recess 11b is heated and melted.

  In FIG. 3, when the clamping operation between the upper mold 2 and the lower mold 3 is completed, the mold clamping mechanism is stopped. At this time, the workpiece W sucked and held by the upper mold insert 7 is clamped by the upper mold insert 7 and the lower mold insert 11, and the semiconductor chip is accommodated in the cavity recess 11b.

  Next, in FIG. 4, the transfer mechanism is operated to raise the plunger 13, and the molten resin in the pot 12a is filled into the cavity recess 11b through the resin passage 12b and the runner gate 11a. Then, it is cured by heating and pressing for a predetermined time (cure).

Here, an example of the temperature adjustment operation of the mold surface temperature (cavity recess) of the cooling device 14 and the second heating device 15 will be described with reference to FIG.
First, in FIG. 6A, when the resin is supplied to the mold 1, the second heating device 15 is operated in advance so that the mold surface temperature is higher than the molding temperature (corresponding to Tl in the figure) ( The granular resin 16b is supplied and forcibly melted, and then the heating of the second heating device 15 is turned off and the cooling device 14 is operated. Molding is performed after the mold surface temperature is lowered to a predetermined molding temperature and stabilized. Thereby, the time required for melting the granular resin 16b can be shortened compared with melting at the molding temperature. At this time, even if the heating of the second heating device 15 is turned off, the temperature is not excessively lowered because the heating is performed by the first heating devices 4a and 9a.

  Further, since the mold surface temperature is easily displaced, the predetermined temperature is maintained while the cooling device 14 or the second heating device 15 is controlled to be turned on / off while the temperature is detected by the second temperature sensor 11c. For example, when the mold surface temperature is lowered by operating the cooling device 14, heating with only the first heating devices 4 a and 9 a returns the temperature when the temperature by the cooling device 14 is excessively lowered. It takes time. However, since the second heating device 15 is provided adjacent to the cooling device 14, the temperature can be raised quickly. Therefore, since the temperature can be rapidly lowered by the cooling device 14, the time required for sealing the workpiece can be shortened. Similarly, even if the temperature is rapidly raised by the second heating device 15, overshoot or the like does not occur. As described above, since the temperature can be quickly adjusted with respect to the mold surface where the temperature is easily displaced, the mold surface temperature (cavity recess 11b) of the mold 1 is finely adjusted within a predetermined temperature range. The temperature can be adjusted accurately with respect to a predetermined set temperature, and can be maintained at the predetermined temperature for a long time.

  Further, as shown in FIG. 6B, when the transfer mechanism is operated after the mold is closed and the workpiece W is clamped, the runner gate 11a side has a high resin flow rate and the temperature is difficult to rise. A heating operation by the device 15 is performed to increase the temperature of the resin to a high temperature (corresponding to Th in the same figure), and the plunger 13 is raised to make it easy to fill the cavity recess 11b with the resin. Further, as shown in FIG. 6C, the cooling operation by the cooling device 14 is performed at a low temperature (corresponding to Tl in the figure) in parallel to increase the viscosity of the resin filled in the cavity recess 11b and decelerate the flow. It is also possible to prevent wire flow from occurring at the time of front contact. In the case of a resin having a curing temperature lower than a temperature suitable for filling with the resin, an appropriate curing temperature can be obtained.

  Moreover, as shown in FIG.6 (d), it can also be made low temperature (equivalent to Tl in the same figure) by performing the cooling operation of the cooling device 14 between completion of mold | curing and mold opening. In this case, after the heating operation of the second heating device 15 is stopped, the cooling operation of the cooling device 14 is performed to lower the surface temperature of the mold 1 to a predetermined temperature, and then the mold opening is performed. As a result, the temperature drop of the resin after the mold is opened and the pressure is released can be reduced, and warping due to shrinkage can be effectively prevented.

  As described above, by controlling the operation of the second heating device 15 or the cooling device 14 in which the cooling device 14 and the second heating device 15 are provided in this order from the side close to the cavity recess 11b, the mold The mold surface temperature (cavity recess 11b) of the mold 1 can be finely adjusted within a predetermined temperature range, and if the resin mold apparatus provided with the mold 1 is used, the molding quality can be improved. it can.

  As the above-mentioned resin in the cavity, a granule resin that is relatively easy to measure is selected. However, a powder resin, a tablet, or the like may be used. As the tablet, in addition to the mini-tablet that is usually mass-produced, various shapes such as a plate shape that is smaller than the cavity and a cylindrical (disk) shape can be adopted. Moreover, although the tablet used the resin in a pot, granule resin, liquid resin, or powder resin may be sufficient.

Further, as the workpiece W of each embodiment, a wafer plate used for WLP (Wafer Level Package) or a carrier plate used for E-WLP (Embedded Wafer Level Package) to which a semiconductor chip is attached can be appropriately employed. Further, it may be a lead frame on which an LED chip is mounted, a QFN, or a ceramic substrate. In addition, various substrates such as a resin substrate or a ceramic substrate on which a flip chip type semiconductor chip is mounted as the workpiece W may be used, and an underfill may be applied while overmolding. Further, the work W does not necessarily have to be mounted with a semiconductor chip, and may be a substrate or a lead frame on which a stiffener for fixing a reflector or a heat sink of the LED is formed. As described above, the workpiece W may be any object used in various resin molding methods, and any workpiece W can obtain the above-described advantageous effects.
In the mold 1, the upper mold 2 is a fixed mold and the lower mold 3 is a movable mold. However, the lower mold 3 may be a fixed mold and the upper mold 2 may be a movable mold, or both may be movable molds.

  In addition, the structure which performs the above-mentioned temperature control operation | movement can also be used for the molding die for compression molding apparatuses. In this case, the same effect as the above-described configuration can be obtained. For example, the mold can be melted positively by supplying a resin other than liquid such as granules, powder, blocks, etc. into the mold with the mold temperature set in advance.

  In addition, the second heating device 15 and the cooling device 14 can be arranged other than the cavity recess 11b to adjust the temperature. For example, a configuration in which the temperature of a runner or a cull is adjusted may be used. The second heating device 15 and the cooling device 14 are preferably provided at a position adjacent to the cavity concave portion 11b filled with the molten resin for the convenience of temperature adjustment reaction, but the surface on which the substrate of the workpiece W is attached. May be provided. In addition, if the cavity concave portion is a mold die formed in both the upper mold 2 and the lower mold 3, the same configuration may be provided for both. In this case, the temperature of the packages on both sides can be made uniform, and warpage can be prevented.

W Work 1 Mold 2 Upper mold 3 Lower mold 4 Upper mold base 4a, 9a First heating device (base heater)
4b, 9b First temperature sensor 5 Upper die chase 6 Upper die center insert 7 Upper die insert 8 Sealing material 9 Lower die base 10 Lower die chase 11 Lower die insert 11a Runner gate 11b Cavity recess 11c Second temperature sensor 12 Pot Insert 12a Pot 12b Resin path 13 Plunger 14 Cooling device 14a Cooling pipe 15 Second heating device 16a Resin tablet 16b Granular resin

Claims (4)

An upper mold base and a lower mold base each provided with a first heating device and a first temperature sensor;
An upper chase supported by the upper mold base and a lower chase supported by the lower mold base;
An upper mold insert and a lower mold insert that are supported by the upper mold chase and the lower mold chase, respectively, so that they can be inserted and removed, and at least one of which has a cavity recess,
At least one of the upper mold chase, the lower mold chase, the upper mold insert, and the lower mold insert is provided with a cooling device and a second heating device in this order from the side close to the cavity recess, and in the vicinity of the cavity recess. A mold mold, wherein a second temperature sensor is provided. The mold according to claim 1, wherein the mold surface temperature of the cavity recess is adjusted and maintained within a desired temperature range by controlling on and off the cooling device and the second heating device . The cooling pipe in which the refrigerant of the cooling device circulates is piped so as to flow in from the front side of the mold, make a U-turn on the back side in the mold longitudinal direction, and flow out from the front side . Mold mold. A resin mold apparatus comprising the mold according to any one of claims 1 to 3.

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