JP5273462B2 - Sealing apparatus and sealing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve productivity by shortening the curing time of a sealing material while keeping a quality of a sealed article. <P>SOLUTION: In the sealing device 100 for sealing a substrate 102 arranged in a cavity 118, the upper mold 106 includes a cull part 136, a clearance 124 facing the cull part 136 and having a bottom surface 126A formed on the cull part side, an elastic member 134 generating a pushing force on the cull part side in the clearance 124, and a ceramic heater 130 having a contact surface 130A getting in thermal contact with the bottom surface 126A through the added force. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a sealing device and a sealing method by transfer molding.

  In the field of mounting electronic components such as semiconductors, a bare chip having a circuit formed by patterning technology such as exposure is cut out from a wafer, mounted on a substrate such as a lead frame, and further connected to an external terminal by wire bonding or the like. There is a process, followed by a resin sealing process. When this resin sealing is performed, a sealing method called transfer molding has been conventionally employed. This method is to inject a molten sealing material into a cavity in which a sealed product such as the substrate is arranged through a mold runner and gate. There is an advantage that it can be sealed.

  In this method, a so-called thermosetting resin that accelerates curing by applying heat is used as a sealing material. Therefore, after the injection of the sealing material is completed, several minutes are spent as a curing time for curing the sealing material.

  In the case of this transfer molding, since there is a variation in the size of the sealing material to be supplied, a buffer unit that absorbs the volume variation of the sealing material is necessary. The buffer portion that absorbs the volume variation is called a cull portion, and is coupled to a plurality of cavities via a runner and a gate. The cull part has a certain thickness in order to secure a certain buffer volume, but the thickness of the cull part is larger than the thickness of the cavity part. There was a problem that it was long compared to the part.

  Therefore, as a technique for shortening the resin curing time of the sealing material, Patent Document 1 discloses a technique in which heating means such as a heater is provided in a mold. Further, in Patent Document 2, as shown in FIG. 10, there is a sealing device configured to provide heat-absorbing and heat generating bodies 16 and 17 in the vicinity of the cull portion 12 and the cavity 14 of the mold in addition to the heater 10. Proposed. The heat absorption and heating bodies 16 and 17 are surrounded by the heat insulators 18 and 19.

  In Patent Document 2, since the cull portion 12 and the cavity 14 are maintained at the melting temperature of the sealing material by the endothermic action of the heat-absorbing and heating elements 16 and 17 when the sealing material is injected, the sealing material Is maintained at an appropriate value, and the injection rate of the sealing material in the cavity 14 can be maintained at an appropriate value. On the other hand, when the injection process of the sealing material is completed, the inside of the cull part 12 and the cavity 14 is heated to the curing temperature of the sealing material by the heat dissipation action of the heat-absorbing and heating elements 16 and 17, and the sealing material is sealed. Curing of the stopping material will be promoted.

JP 2007-287925 A JP 2000-91367 A

  In the technique described in Patent Document 1, “the entire first upper mold can be heated by the heat generated by the heating source, so that the cal part, the runner, It is possible to minimize the occurrence of temperature distribution in each part such as cavities, especially each part of the substrate surface, and effectively prevent problems such as "warping" in the product. It is said. In other words, this technique does not aim to heat only the vicinity of the cull portion with the heat generated by the heating source, and it is difficult to efficiently heat only the vicinity of the cull portion. In addition, since it is necessary to use a heating source having a capacity capable of heating the entire first upper mold, a problem arises in that a heating source having a larger capacity must be used than a heating source that heats only the vicinity of the cull portion. was there.

  Moreover, in the technique described in Patent Document 2, there is a problem that it is difficult to perform active control such as freely changing the period and timing of heat absorption and heat dissipation due to the function of the “heat absorption and heating element”. there were.

  In the present invention, by locally heating the local part of the cal part with a planar heater installed facing the cal part, the quality of the sealed product is maintained and the curing time of the sealing material is shortened. An object of the present invention is to provide a sealing device and a sealing method capable of improving productivity.

  The present invention provides a sealing device that injects a molten sealing material into a cavity constituted by a first mold and a second mold, and seals an article to be sealed disposed in the cavity. The first mold is provided with a cull portion and a gap facing the cull portion and having a bottom surface formed on the cull portion side, and is pushed toward the cull portion inside the gap. By providing an elastic member that generates pressure and a planar heater provided with a contact surface that is applied with the pressing force and is in thermal contact with the bottom surface, the above problem is solved.

  In the present invention, a planar heater is used to heat the sealing material for the cull portion. The planar heater is disposed so that a pressing force is applied and the bottom surface is in thermal contact with the bottom surface in a gap having a bottom surface formed on the cull portion side. At that time, the planar heater is disposed on the bottom surface of the gap “facing” the cull portion. For this reason, the contact surface of the planar heater is substantially parallel to the upper surface of the cull portion, the distance is relatively short, and the contact surface of the planar heater is not extremely large. Therefore, the thermal influence on the cavity for sealing the sealed product can be reduced, and the sealing material for the cull portion can be effectively heated. At that time, since the planar heater can be heated uniformly within the contact surface, the entire cull portion can be heated uniformly. That is, a homogeneous curing reaction of the sealing material can be promoted.

  Also, the sheet heater is not “fixed” to the bottom surface of the gap, but is pressed by an elastic member and brought into thermal contact with the bottom surface, so that the thermal expansion between the mold (bottom surface of the gap) and the sheet heater is performed. Even if there is a difference in rate, the influence of mutual thermal stress can be reduced. For this reason, it is possible to prevent the planar heater from being damaged by the thermal cycle, and to ensure a stable operation of the planar heater.

  Here, “thermal contact” means contact for heat conduction without a member for heat insulation between the contact surface of the planar heater and the bottom surface of the cull part. Say. Specifically, the contact surface of the planar heater and the bottom surface of the cull portion may be in direct contact with each other, and a thermal conductive grease or a thermal conductive sheet for improving thermal conductivity is interposed between them. May be.

  Further, when the planar heater has a width equal to or smaller than the width of the cull portion in the direction from the cull portion to the cavity, the sealing device is enlarged. As a result, it becomes easy to incorporate a planar heater, and a large design change of the sealing device can be eliminated, and the cull portion can be efficiently heated. Here, the relationship between the width of the cull part and the width in the direction from the cull part to the cavity is such that the width of the planar heater is slightly larger than the width of the cull part from the viewpoint of “heat” that causes fluctuation to some extent. Is also included.

  Further, when a gap is provided between the side surface of the gap with respect to the bottom surface and at least one side surface with respect to the contact surface of the planar heater, the gap insulates heat generated by the planar heater. can do. For this reason, the conduction of heat to the side surface with respect to the bottom surface of the gap can be reduced, the influence of heat on the cavity can be further reduced, and the cull portion can be heated more effectively.

  Further, when the side surface of the air gap with respect to the bottom surface and the side surface of the planar heater with respect to the contact surface do not contact each other, for example, when the planar heater is square in a plan view, it may be in contact only at the corner. Though conceivable, heat dissipation from the side surface of the planar heater with respect to the contact surface is blocked. For this reason, the conduction of heat to the side surface with respect to the bottom surface of the gap can be reduced, the influence of heat on the cavity can be extremely reduced, and the cull portion can be heated more effectively.

  In addition, when a heat insulating member is disposed between the planar heater and the elastic member, it is possible to prevent the heat generated by the planar heater from diffusing to the anti-cull portion side and more effectively. The cull portion can be heated.

  Further, in the case where the heat insulating member is provided with a recess for fitting with the surface heater, the heat insulating member can position the surface heater which is a heating means of the cull portion. The curing reaction can be stabilized more uniformly by stabilizing the position.

  The planar heater is not particularly limited. However, in the case of a ceramic heater, a large watt density can be used as the planar heater. Can be efficiently heated, and the curing rate of the material for sealing the cull portion can be further increased. At the same time, by using a material having a small heat capacity, a rapid temperature rise is possible, and the temperature control of the sealing material for the cull portion can be performed actively in real time. In doing so, the ceramic heater can minimize and optimize the watts required to heat the cull. For this reason, even if it repeats a resin sealing process, the accumulation | storage of the heat | fever in the cavity which seals a sealing product can be minimized, and the influence can be avoided.

The planar heater is not particularly limited numerically. However, watt density of the planar heater, if it is 15W / cm ² or more 55W / cm ² or less is more preferable conditions. Moreover, it is a more preferable condition that the thickness of the planar heater is 0.5 mm or more and 4 mm or less. Furthermore, it is a more preferable condition that the distance between the contact surface and the upper surface of the cull portion is 3 mm or more and 10 mm or less.

  In addition, in the case where a means for causing the planar heater to function at the completion of injection of the molten sealing material into the cavity is provided, the sealing material in the cavity is minimally affected by the planar heater. Therefore, it is possible to shorten the time until the sealed product is taken out without changing the conditions of the resin injection process in the existing sealing device. In other words, since existing process control can be used, process development is not expensive, and productivity can be improved at low cost.

  In addition, when a means for operating the planar heater is provided during the injection of the molten sealing material into the cavity, or at or before the start of the injection, the time until removal of the sealed product is set. Furthermore, since it can shorten, productivity can be improved more.

  In the sealing method of injecting a molten sealing material into a cavity constituted by a mold and sealing an object to be sealed disposed in the cavity, the mold of the sealing material In the process from the supply to the cavity until it is cured to the required hardness in the cavity, a planar heater that opposes the cull part provided in the mold and is pressed against the mold by an elastic member and is in thermal contact with the mold The corresponding effect of the present invention can also be obtained by a sealing method characterized by including a functioning step.

  According to the present invention, productivity can be improved by shortening the curing time of the sealing material while maintaining the quality of the sealed product.

Sectional drawing which showed typically the principal part of the sealing device which concerns on 1st-3rd embodiment of this invention. Fig. 1 is an enlarged schematic view of the vicinity of the cull part. Table showing the results of investigating preferred operating conditions when operating the ceramic heater A graph showing an example of the operating conditions of the ceramic heater shown in FIG. A graph showing the temperature fluctuation of a specific part of the mold when the ceramic heater is functioned repeatedly The figure which showed the relationship between the resin hardening degree which concerns on 1st Embodiment of this invention, and time. The figure which showed the relationship between the resin hardening degree which concerns on 2nd Embodiment of this invention, and time. The graph which shows the temperature change of the metal mold | die of the cull part upper surface center position at the time of not using the heater which concerns on 3rd Embodiment of this invention. The figure which showed the relationship between the resin hardening degree which concerns on 3rd Embodiment of this invention, and time. Sectional drawing which showed the conventional sealing device typically

  Hereinafter, an example of the first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  1 is a cross-sectional view schematically showing a main part of a sealing device according to a first embodiment of the present invention, FIG. 2 is an enlarged schematic view in the vicinity of a cull portion of FIG. 1, and FIG. 3 operates a ceramic heater. FIG. 4 is a graph showing an example of the operating conditions of the ceramic heater shown in FIG. 3, and FIG. 5 is a graph showing the molds when the ceramic heater is repeatedly functioned. FIG. 6 is a graph showing the temperature fluctuation at a specific location, and FIG. 6 is a diagram showing the relationship between the resin curing degree and time. Note that FIG. 1 schematically shows an outline of the sealing device focusing on its function, and does not necessarily match the specific configuration of the actual device.

  First, a schematic configuration of the sealing device will be described with reference to FIG.

  The mold 104 of the sealing device 100 includes an upper mold 106 that is a first mold and a lower mold 108 that is a second mold. Cartridge heaters (not shown) for heating the upper mold 106 and the lower mold 108 are embedded in the upper mold 106 and the lower mold 108, respectively, and in this embodiment, the temperature is maintained at a constant temperature (for example, about 175 degrees). In the present invention, it is not always necessary to keep the temperature of the mold 104 constant.

  The upper mold 106 is further divided into upper and lower parts so as to divide the gap 124, and is mainly composed of a first upper mold 110 and a second upper mold 112 that is superimposed on the first upper mold 110. The first upper mold 110 is provided with a part of the cavity 118 (upper cavity 120) and a cull part 136 for sealing (resin-sealing) the substrate 102, which is an article to be sealed. The second upper mold 112 is attached to the fixed platen via a mounting block, a support plate, etc. (not shown).

  On the other hand, the runner 138, the gate 140, and a part of the cavity 118 (lower cavity 122) are formed in the lower mold 108. A cylindrical pot 142 is formed on the lower mold 108. A resin tablet 146 serving as a sealing material is disposed in the pot 142, and the resin tablet 146 is compressed by the upward movement of the plunger 144 disposed below. The melted sealing material is pumped to the cavity 118 via the cull portion 136, the runner 138, and the gate 140. The lower mold 108 is fixed to the movable platen via a mounting block (not shown), a support plate, and the like. The movable platen is connected to a pressing device (not shown), and by driving the pressing device, the lower die 108 can be moved toward and away from the upper die 106, and the die 104 is closed, clamped and clamped. Open it. Therefore, the sealing device 100 injects the melted sealing material into the cavity 118 constituted by the upper mold 106 and the lower mold 108 to transfer-mold (seal) the substrate 102 disposed in the cavity 118. be able to. However, in the present invention, either the upper mold or the lower mold may be movable.

  Hereinafter, each component will be described in more detail.

  As shown in FIG. 1, the first upper mold 110 has a cull part 136, first and second recesses 114 and 116 in which a substrate 102 to be sealed is disposed, and a cavity into which a sealing material is injected. An upper cavity 120 corresponding to the upper side of the substrate 102 of 118 is provided. Further, the first upper mold 110 is directly provided with a third recess 126 that constitutes the divided gap 124.

  As shown in FIG. 1, the cull portion 136 is for guiding the molten sealing material to the cavity 118 through the runner 138 and the like, and the first upper mold 110 has a disk-shaped depression ( For example, the diameter is 30 mm or less. The cull unit 136 also has a function of securing a certain buffer volume. Therefore, the thickness of the cull part 136 is several times as large as the thickness of the cavity 118. As shown in FIG. 2A, the diameter D3 of the upper surface 136A is smaller than the diameter D2 of the bottom surface portion of the cull portion 136 (D2> D3). For this reason, angle (theta) is larger than 0 degree | times and can make the molten sealing material flow smoothly. In addition, when the cured sealing material for the cull portion 136 is released from the first upper mold 110, it is easy to release because the draft is given by the angle θ.

  As shown in FIG. 1, the third recess 126 is a rectangular depression, and is provided in the first upper mold 110 directly above the cull part 136, that is, facing the cull part 136. The width D1 of the bottom surface 126A provided on the side of the third recess 126 on the side of the cull portion in the direction from the cull portion 136 to the cavity 118 (hereinafter simply referred to as the X direction) is as shown in FIG. A diameter D3 larger than the diameter D3 of the upper surface 136A of 136 (D1> D3) is substantially equal to the diameter D2 of the cull portion 136 (D1≈D2). That is, the width (diameter D2) of the cull portion 136 and the width D1 of the bottom surface 126A (of the gap 124) in the X direction are substantially equal. Further, the distance between the bottom surface 126A and the upper surface 136A of the cull portion 136 is constant (parallel). A ceramic heater 130 which is a planar heater is disposed on the bottom surface 126A.

  In general, a planar heater has a structure in which a heating resistor is sandwiched between insulators, and can be heated uniformly in the plane. At that time, when the heat generated in the heating resistor is transmitted to the heater surface in a short time, it is preferable to use an insulator having a high thermal conductivity (for example, about 10 to 40 W / mK). Further, in the case where the cull part 136 is heated at an appropriate temperature, the planar heater is heated from the same temperature (for example, about 175 degrees) as the mold (upper mold 106, lower mold 108) to several tens to hundreds of degrees. Since the temperature rises, the insulator preferably has high heat resistance (for example, 500 degrees or more). As described above, it is preferable that the planar heater has not only high insulation but also high temperature and high heat resistance, a high temperature rising rate, and a long life, and alumina and aluminum nitride satisfy these conditions. A ceramic heater 130 using a ceramic substrate such as is suitable.

  The ceramic heater 130 is formed by embedding a heating resistor (for example, a high melting point metal such as platinum, tungsten, or molybdenum) as a wiring pattern in a ceramic substrate (a ceramic heating insulator is sandwiched between insulators). Structure), heat can be generated uniformly within the surface of the ceramic substrate. That is, the ceramic heater 130 can generate heat uniformly within the surface of the lower surface (also simply referred to as a contact surface) 130A of the ceramic heater 130 that contacts the bottom surface 126A.

  The thickness of the ceramic heater 130 is basically small, thin, and lightweight as long as ceramic is used as the substrate. However, since ceramic is a brittle material and easily breaks, it is better to increase the thickness from handling. However, if the thickness is large, the heat capacity of the ceramic substrate increases, and even if the heating resistor becomes hot, it takes time for the surface of the ceramic substrate to become hot, which is not preferable for heating the cull portion 136 in a short time. At the same time, if the heat capacity is large, it takes time for the temperature once raised to drop, and even if the function of the ceramic heater 130 is stopped, a later operation cycle is delayed. For this reason, the thickness of the ceramic heater 130 may be reduced. However, if the thickness is too thin as described above, the ceramic heater 130 is easily broken and thus difficult to manufacture and handle. For this reason, the thickness of the ceramic heater 130 is preferably in the range of 0.5 mm to 4 mm.

  In addition, since the ceramic heater 130 can freely design the wiring pattern of the heating resistor, it can basically generate heat at a high watt density. In that sense, a higher watt density is desirable for heating the sealing material of the cull portion 136 in a short time. However, if the watt density is too high, the conduction of heat to the parts other than the cull portion 136 is increased, and a temperature difference is given to each part of the cavity 118 that seals the sealed product, and the sealed product may be warped. There is. On the other hand, when the watt density is low, the curing time of the sealing material of the cull portion 136 cannot be shortened so much and the heating effect becomes low. The resin curing time is related not only to the watt density but also to the functional time of the ceramic heater 130. That is, if the function time is long, the above-described warpage of the sealed product is likely to occur, and conversely, if the function time is short, the degree of shortening of the resin curing time becomes small. Therefore, a more preferable watt density of the ceramic heater 130 and a time for functioning the ceramic heater 130 are obtained by using a heat transport simulation and Kamal's formula (an empirical formula showing the relationship between the temperature change of the thermosetting resin and the resin curing degree). The relationship was examined. In this calculation, the parameter values described in the reference (Yasutada Nakagawa: Transactions of the Japan Society of Mechanical Engineers (C), Vol. 72, No. 713 (2006), 1-6) were adopted as the parameter values of Kamal's formula. . The calculation procedure will be described below.

  First, the temperature of the sealing material for each time passage of the cull part 136 and the cavity 118 is calculated by a heat transport simulation. Next, the degree of resin curing for each elapsed time is calculated from the calculated temperature data of the calorie part 136 and the Kamal equation, and the time (resin curing time) at which the sealed product can be taken out is determined. The results of evaluating the watt density of the ceramic heater 130 and the time for the ceramic heater 130 to function are shown in the table of FIG. Here, the condition 1 is the case where the resin curing time of the sealing material is the case where the heating is performed by the ceramic heater 130 when the resin curing time is 60 seconds when the heating by the ceramic heater 130 is not performed. The curing time is 30 seconds or shorter, that is, the resin curing time is half or shorter. In condition 2, if the temperature rise of the cavity 118 is within about 2 degrees, there is no problem in the sealed product, and the temperature rise of the cavity 118 is 2 degrees or less. The results of FIG. 3 will be described below.

When the watt density of the ceramic heater 130 is 15 W / cm ² , the temperature rise of the cavity 118 is within 2 degrees even if the time for the ceramic heater 130 to function is about 20 seconds, but about 20 seconds to reduce the resin curing time by half. Since the above is necessary, the time for the ceramic heater 130 to function is appropriately about 20 seconds or more.

When the watt density of the ceramic heater 130 is 25 W / cm ² , it takes about 10 seconds or more for the ceramic heater 130 to function for halving the resin curing time, while suppressing the temperature rise of the cavity 118 within 2 degrees. Therefore, it is necessary to set the ceramic heater 130 to function for about 10 seconds to about 15 seconds.

When the watt density of the ceramic heater 130 is 35 W / cm ² , it takes about 10 seconds or more for the ceramic heater 130 to function for halving the resin curing time, while the temperature rise of the cavity 118 is suppressed to within 2 degrees. Therefore, it is necessary to set the ceramic heater 130 to function for about 10 seconds.

When the watt density of the ceramic heater 130 is 45 W / cm ² , in order to reduce the resin curing time by half, the time for the ceramic heater 130 to function may be about 5 seconds, while to suppress the temperature rise of the cavity 118 within 2 degrees. Since it is necessary to set it to about 5 seconds or less, the time for which the ceramic heater 130 is operated is appropriately about 5 seconds or less.

When the watt density of the ceramic heater 130 is 55 W / cm ² , in order to reduce the resin curing time by half, the time for the ceramic heater 130 to function may be about 5 seconds. On the other hand, the temperature rise of the cavity 118 is within 2 degrees. Since it is necessary to make it about 5 seconds or less in order to suppress it, the time for which the ceramic heater 130 is made to function is about 5 seconds or less.

When the watt density of the ceramic heater 130 exceeds 55 W / cm ² , the temperature rise of the cavity 118 can be kept within 2 degrees even if the time for the ceramic heater 130 to function is shorter than about 5 seconds in order to reduce the resin curing time by half. Presumably difficult to suppress. Further, when the watt density of the ceramic heater 130 is less than 15 W / cm ² , the watt density is too low, and it is difficult to reduce the resin curing time by half even if the time for the ceramic heater 130 to function is about 20 seconds or more. It is estimated that.

Therefore, in the present embodiment, watt density of the ceramic heater 130 is 15W / cm ² or more 55W / cm ² or less, the time to function the ceramic heater 130 is 20 seconds or less than 5 seconds, respectively appropriate. Similarly, the resin curing time when no heating with the ceramic heater 130 is evaluated by calculations for the case of 120 seconds, watt density of the ceramic heater 130 is 15W / cm ² or more 55W / cm ² or less, the ceramic heater 130 It is appropriate that the functioning time is 5 seconds or more and 40 seconds or less. Here, the upper limit of the time for the ceramic heater 130 to function is about 1/3 of the resin curing time when the ceramic heater 130 is not heated. Therefore, it is appropriate that the time for which the ceramic heater 130 is functioned be 5 seconds or longer and not more than 1/3 of the resin curing time when heating by the ceramic heater 130 is not performed. That is, in the present embodiment, the ceramic heater 130 does not have to function over the entire resin curing time.

An example satisfying the above condition is shown in FIG. In FIG. 4, the watt density of the ceramic heater 130 is 35 W / cm ² , and the time for the ceramic heater 130 to function is 10 seconds. The graph TC indicates the temperature at the center of the sealing material of the cull portion 136, and the graph HN indicates the degree of cure at the center of the sealing material of the cull portion 136. In order to take out the sealed product, the degree of cure of the sealing material needs to be about 95%. The graph HN has a degree of cure of 95% in about 20 seconds, and it can be seen that the sealing material is cured and can be taken out within 30 seconds.

  As a means for causing the ceramic heater 130 to function, the simplest method is to turn it on and off, the power supply circuit can be simplified, and cost reduction and reliable heat generation control can be realized. At the same time, the heat generation operation of the ceramic heater 130 that rapidly increases in temperature can be controlled. However, the present invention is not limited to this, and the ceramic heater 130 may function by other methods. For example, PWM (pulse width modulation) or the like can be used as the functional means, and the thermal shock to the ceramic heater 130 can be reduced by easily changing the power supply amount to the ceramic heater 130 in an analog manner. It is possible to extend the life of 130.

  As shown in FIG. 2A, the width d1 of the ceramic heater 130 in the X direction is smaller than the width D1 of the bottom surface 126A of the third recess 126 (D1> d1). Since the ceramic heater 130 can be disposed on the bottom surface 126A without being inclined, the distance between the upper surface 136A of the cull portion 136 and the lower surface (contact surface) 130A of the ceramic heater 130 can be made constant (that is, parallel). In this embodiment, the width d1 in the X direction of the ceramic heater 130 is set to be slightly smaller than the diameter D2 of the bottom surface portion of the cull portion 136 (d1 <D2). For this reason, in addition to heating the cull portion 136, the thermal influence on other portions can be minimized. Such an effect is obtained until the width d1 is substantially equal to the diameter D2 of the bottom surface portion in the cull portion 136 (d1≈D2). The ceramic heater 130 is square or rectangular in plan, and the cull portion 136 is a circular depression and is intended for “heat”, so this magnitude relationship is not strict.

  Further, as shown in FIG. 2A, because of the “facing” relationship, the distance d2 between the contact surface (lower surface 130A) and the upper surface 136A of the cull portion 136 is shorter than the width d1 of the ceramic heater 130. The width (diameter D2) of the cull portion 136 and the width D1 of the bottom surface 126A of the third recess 126 are substantially equal. Therefore, the upper surface 136A of the cull portion 136 is not greatly distorted by the injection pressure of the sealing material, and the mold 104 can have a long life. Furthermore, since the ceramic heater 130 generates heat uniformly in the plane, the ceramic heater 130 can uniformly heat the cull portion 136 without deviation. Note that the width D1 of the bottom surface 126A of the third recess 126 does not necessarily have to be substantially equal to the width D2 of the cull portion 136. Even if the width D1 is increased to such an extent that it is not greatly distorted by the injection pressure of the sealing material. good.

  More specifically, the distance d2 between the contact surface (lower surface 130A) and the upper surface 136A of the cull part 136 is more preferably 3 mm or more and 10 mm or less. When the plunger 144 is raised and the sealing material is injected into the cavity 118, a high pressure (for example, 10 to 20 MPa) is applied to the upper surface 136A of the cull portion 136. Due to this high pressure, the upper surface 136A of the cull portion 136 is distorted, and the bottom surface 126A of the opposed third recess 126 is also distorted, which may reduce the contact area between the bottom surface 126A and the contact surface (lower surface 130A). . That is, when the contact area decreases, the heating of the cull portion 136 becomes insufficient, and the temperature of the ceramic heater 130 rises too much, so that the heating resistor of the ceramic heater 130 may be disconnected. If the distance d2 mentioned above is 3 mm or more, such a fear can be avoided in this embodiment. The reason why the distance d2 is 10 mm or less is that the cull part 136 can be heated effectively in a shorter time. In addition, although such a numerical value is limited to this embodiment, in other embodiment, it can obtain | require suitably by experiment etc.

  In addition, the side surface of the third recess 126 with respect to the bottom surface 126A (also referred to as the side surface of the gap 124 with respect to the bottom surface 126A or simply the side surface of the space 124) 126B and the side surface 130C with respect to the contact surface (lower surface 130A) of the ceramic heater 130 (simply referred to as the ceramic heater 130). (Also referred to as a side surface 130C) as shown in FIG. 2 (A). Since the thermal conductivity of air is as low as one hundredth to several thousandth that of ceramic, heat C generated from the side surface 130C of the ceramic heater 130 due to the presence of the gap 125 (FIG. 2A) Is cut off, the heat B diffusing around the cull portion 136 is small, and the heat A for heating the cull portion 136 is large, so that the heat conduction to other than the cull portion 136 can be effectively reduced. However, the case where the side surface of the ceramic heater 131 abuts on the side surface 127B of the third recess as shown in FIG. 2B is not excluded. This is because the ceramic heater 131 originally generates heat uniformly in the surface, so that the heat A to the cull portion 137 is overwhelmingly large and brings about a corresponding effect.

  As a method of arrangement for “thermal contact” of the ceramic heater 130, the ceramic heater 130 may be in direct contact with the bottom surface 126 </ b> A of the third recess 126, or may be in thermal contact with the heat conduction sheet. However, in this embodiment, the thermal contact with the bottom surface 126A of the third concave portion 126 is ensured by applying the heat conductive grease to the lower surface 130A of the ceramic heater 130. As the thermal conductive grease, silicon grease mixed with a filler having high thermal conductivity can be used. Note that siloxane may be generated from silicon grease, and when generation of siloxane becomes a problem, non-silicone grease may be used.

  As shown in FIG. 1, the ceramic heater 130 is given a pressing force by an elastic member 134 through a heat insulating member 132. The elastic member 134 applies a pressing force to press the ceramic heater 130 and the heat insulating member 132 toward the bottom surface 126 </ b> A of the third recess 126 within the gap 124 formed by the third recess 126 and the fourth recess 128. generate. Specifically, a compressed spring (coil spring, leaf spring, disc spring, etc.), rubber having high heat resistance, or the like can be used as the elastic member 134. As shown in FIG. 1, since the elastic member 134 is provided with a gap 134A on both sides thereof, even if the thermal conductivity of the elastic member 134 itself is high, the heat is insulated by the gap 134A. Can be reduced. Here, the thermal expansion coefficient differs between the ceramic substrate of the ceramic heater 130 and the bottom surface 126 </ b> A (metal) of the third recess 126. However, by using the elastic member 134 in combination with the use of the thermal conductive grease, the lower surface 130A of the ceramic heater 130 and the bottom surface 126A of the third recess 126 do not give stress due to thermal expansion. At this time, even if the ceramic heater 130 is not fixed to the bottom surface 126 </ b> A of the third recess 126, the heat of the ceramic heater 130 can be efficiently transferred to the cull portion 136 by making it come into thermal stable contact. For this reason, it is possible to avoid applying stress to each other even when the temperature of the ceramic heater 130 rises, and it is possible to avoid occurrence of problems such as cracking of the ceramic heater 130 due to fixing.

  As shown in FIG. 2A, the heat insulating member 132 is a plate-like member, and is provided with a concave portion 132A for fitting and positioning the ceramic heater 130 on the surface on the cull portion side. The width of the recess 132A is slightly larger than the width d1 of the ceramic heater 130, and the recess 132A is provided at the center of the heat insulating member 132. For this reason, the uniform gap 125 can be stably ensured at the both ends of the ceramic heater 130 by the positioning. As the heat insulating member 132, a material having high heat resistance (for example, heat resistance of 200 ° C. to 500 ° C.) and low thermal conductivity (for example, a material mainly containing glass fiber or mica) can be used.

  Note that the heat insulating member 132 is not necessarily used. However, by using the heat insulating member 132, the heat transmitted to the elastic member 134 can be thermally insulated and the heat diffused to the side opposite to the cull portion of the ceramic heater 130 can be positively conducted to the cull portion 136. Efficient heating can be realized. At the same time, local stress concentration when the elastic member 134 locally presses the ceramic heater 130 can be avoided, so that problems such as cracks in the ceramic heater 130 can be prevented and the life of the ceramic heater 130 can be extended. Is possible.

  Next, a procedure for incorporating the ceramic heater 130 into the gap 124 in this embodiment will be described below.

  First, thermal conductive grease is applied to the lower surface 130 </ b> A of the ceramic heater 130, and the ceramic heater 130 is placed on the bottom surface 126 </ b> A of the third recess 126 with a certain pressing force. At that time, it is arranged (thermally contacted) so that air does not enter between the bottom surface 126A of the third recess 126 and the lower surface (contact surface) 130A of the ceramic heater 130. The heat insulating member 132 is inserted into the third recess 126, and the ceramic heater 130 is fitted into the recess 132A to adjust the position. Then, the elastic member 134 is disposed on the heat insulating member 132. When the fourth recess 128 formed in the second upper mold 112 is aligned with the third recess 126, it is confirmed that the elastic member 134 is compressed by the fourth recess 128, and the first upper mold 110 and The second upper mold 112 is fixed with a bolt or the like (not shown).

  Next, FIG. 5 shows the result of examining the heat accumulation state in the mold 104 when the ceramic heater 130 is repeatedly functioned when the above-described more preferable conditions of the ceramic heater 130 are satisfied. FIG. 5 shows the result of performing the cycle 100 times with the process cycle in which the ceramic heater 130 is functioned being about one minute. FIG. 5 (A) shows temperature changes in 1 to 10 cycles and 91 to 100 cycles of the position Q on the cull side of the end of the upper cavity 120. FIG. 5 (B) shows temperature changes in 1 to 10 cycles and 91 to 100 cycles of the position P at the center of the upper surface 136A of the cull portion 136. FIG.

  In synchronism with the process cycle of the ceramic heater 130, the temperature changes at about 50 degrees with respect to the reference temperature (about 175 degrees) at the position P, but the temperature rises only slightly at the position Q. The change is also very small. Moreover, even if it sees even if it overlaps 1-10 cycles and 91-100 cycles, the temperature cycle of 1-10 cycles and 91-100 cycles has overlapped substantially in the position P and Q. That is, it can be seen that even if the ceramic heater 130 is repeatedly functioned, the heat accumulation state hardly changes in the cull portion 136 and the cavity 118.

  Next, a resin sealing procedure in this embodiment will be described.

  The transfer molding process is a process consisting of a machine time process, a resin injection process, and a resin curing process, and forms one cycle. In the machine time step, the mold 104 is opened to take out the sealed sealed product, the mold 104 is brushed, and the substrate 102 and the sealing material (resin tablet 146), which are the sealed products, are removed. It is a process of setting, mold closing, and mold clamping. The resin injection process is a process in which the sealing material is melted and injected into the cavity 118 for sealing the sealed product. The resin curing step is a step of curing the sealing material until the hardness is such that the sealed product can be taken out. The thermosetting resin used as the sealing material has a property of being melted and then cured when given heat. Therefore, the higher the temperature applied to the sealing material, the shorter the time required for curing. . Therefore, in order to shorten the curing time, the mold 104 should be set as high as possible. However, if the temperature exceeds a certain temperature, the sealing material is cured during the injection of the sealing material and the sealing is performed. It will stop. For this reason, the mold 104 is set to a temperature suitable for the sealing material to be used. Below, it demonstrates using FIG. 1 focusing on the resin injection | pouring process and the resin hardening process among 1 cycle of a resin sealing process.

  First, in a state where the plunger 144 is placed at the lower limit position in the pot 142, the resin tablet 146 is set in the pot 142, and the plunger 144 rises.

  Next, the resin tablet 146 is pumped by the rise of the plunger 144 while being melted by the heat from the mold 104 and the plunger 144, and the inside of the cavity 118 that seals the sealed product through the cull portion 136, the runner 138, and the gate 140. Injected into.

  After the injection into the cavity 118 is completed, the ceramic heater 130 functions and the cull part 136 is heated for several seconds to several tens of seconds while being clamped by the upper mold 106 and the lower mold 108. The ceramic heater 130 is caused to function by a control unit (not shown) of the sealing device 100.

  After the function of the ceramic heater 130 is stopped, the mold is opened when the sealing material is cured, and the sealed sealed product is taken out.

  FIG. 6 shows a resin curing step in resin sealing according to this embodiment. The graph of the code | symbol H1 represents the mode of resin curing in this embodiment, and the graph of the code | symbol R represents the mode of conventional resin curing without a ceramic heater. The state of the resin curing here is intended for the sealing material of the cull portion 130 that controls the resin curing time.

  In the present embodiment, for example, the control unit (not shown) of the sealing device 100 functions and heats the ceramic heater 130 at the time T1 when the resin injection step t1 is completed, whereby the curing is completed in the conventional resin curing step. It is possible to shorten the time t2 required for the time to the time t3. That is, the resin curing step can be shortened by time t4 (= t2-t3). The time t4 can also be said to be a reduction in time from the start of the resin injection process to the hardness at which the sealed product can be taken out. In this embodiment, since the ceramic heater 130 is caused to function when the resin injection process is completed, the process is the same as the conventional resin sealing process until the injection into the cavity 118 is completed. Since the heat of the ceramic heater 130 has little influence on the sealing material in the cavity 118, the sealing is performed from the time when the resin injection process is completed without changing the resin injection process in the existing sealing device 100. The time until the product is taken out can be shortened. That is, since the process related to the cavity 118 for sealing the conventional sealed product can be used as it is, the conventional manufacturing know-how can be inherited as it is, and a high-quality sealed product can be manufactured. At the same time, the cost of process change can be minimized, and the resin sealing process can be accelerated at low cost. That is, since existing processes can be used, process development is not expensive and productivity can be improved at low cost.

  Further, the ceramic heater 130 is used to heat the sealing material of the cull portion 136. The ceramic heater 130 is disposed in a space 124 formed with a bottom surface 126A on the cull portion side so that a pressing force is applied and the bottom surface 126A is in thermal contact with the contact surface 130A. At this time, the ceramic heater 130 is disposed on the bottom surface 126 </ b> A of the gap 124 “facing” the cull portion 136. Therefore, specifically, the distance d2 between the lower surface 130A (contact surface) of the ceramic heater 130 and the upper surface 136A of the cull portion 136 is substantially constant (parallel), and the distance is the width d1 of the ceramic heater 130 in the X direction. Shorter relationship. For this reason, the thermal influence on the cavity 118 that seals the sealed product can be reduced, and the sealing material of the cull portion 136 can be effectively heated. At that time, since the ceramic heater 130 can be uniformly heated within the contact surface 130A, the entire cull portion 136 can be uniformly heated. That is, a homogeneous curing reaction of the sealing material can be promoted. Further, since the ceramic heater 130 can be used as a planar heater having a large watt density, it is possible to efficiently heat the thick cull portion 136 while being small in size. The curing rate can be further increased. At the same time, the heat capacity can be reduced, the temperature can be increased rapidly, and the temperature control of the sealing material of the cull portion 136 can be performed in real time in an active manner. In doing so, the ceramic heater 130 can minimize and optimize the watts required to heat the cull 136. For this reason, even if the resin sealing step is repeatedly performed, it is possible to minimize the accumulation of heat in the cavity 118 for sealing the sealed product and to avoid the influence.

  Further, the ceramic heater 130 is not “fixed” to the bottom surface 126A of the gap 124, but is pressed by the elastic member 134 and is brought into thermal contact with the bottom surface 126A. ) And the ceramic heater 130, the influence of the mutual thermal stress can be reduced. For this reason, it is possible to avoid the ceramic heater 130 from being damaged by the thermal cycle, and to ensure a stable operation of the ceramic heater 130.

  In addition, since the ceramic heater 130 has a width d1 that is smaller than or substantially equal to the width (diameter D2) of the cull portion 136 in the X direction, the ceramic heater 130 can be easily incorporated without increasing the size of the sealing device 100. And the big design change of the sealing device 100 can be made unnecessary, and the cull part 136 can be heated efficiently. At this time, since it is not necessary to change the design of the most important part (cavity 118) as the mold 104, there is almost no problem of an increase in cost for carrying out the invention even in view of the configuration.

  Further, since the gap 125 is provided between the side face 126B with respect to the bottom face 126A of the gap 124 and both side faces (both ends) with respect to the contact face 130A of the ceramic heater 130 and is not in contact with each other, the gap 125 is generated in the ceramic heater 130. Heat can be insulated. For this reason, the conduction of heat to the side face 126B through the gap 125 can be reduced, the influence of the heat on the cavity 118 can be further reduced, and the cull part 136 can be heated more effectively.

  Further, since the heat insulating member 132 is disposed between the ceramic heater 130 and the elastic member 134, the heat generated in the ceramic heater 130 is prevented from diffusing to the anti-cull side, and the cull portion is more effectively prevented. 136 can be heated.

  Further, since the heat insulating member 132 is provided with a concave portion 132A for fitting with the ceramic heater 130, the heat insulating member 132 can position the ceramic heater 130 as a heating means to the cull portion 136. The amount of heat can be stabilized in position to stabilize the curing reaction more uniformly.

  Therefore, according to the present invention, productivity can be improved by shortening the curing time of the sealing material while maintaining the quality of the sealed product.

  Next, an example of the second embodiment of the present invention will be described. FIG. 7 shows a resin curing step in resin sealing according to the present embodiment. The graph of the code | symbol H2 represents the mode of resin curing in this embodiment, and the graph of the code | symbol R represents the mode of conventional resin curing without a ceramic heater. The present embodiment is the same as the first embodiment regarding the structure of the sealing device, but the resin sealing process is different. Hereinafter, the resin injection process and the resin curing process will be mainly described with reference to FIG.

  First, in a state where the plunger 144 is placed at the lower limit position in the pot 142, the resin tablet 146 is set in the pot 142, and the plunger 144 rises.

  Next, the resin tablet 146 is pumped by the rise of the plunger 144 while being melted by the heat from the mold 104 and the plunger 144, and the inside of the cavity 118 that seals the sealed product through the cull portion 136, the runner 138, and the gate 140. Injected into.

  During the injection into the cavity 118, the ceramic heater 130 is operated to heat the cull portion 136 for several seconds to several tens of seconds. The ceramic heater 130 is caused to function by a control unit (not shown) of the sealing device 100.

  After the function of the ceramic heater 130 is stopped, the mold is opened when the sealing material is cured, and the sealed sealed product is taken out.

  In the present embodiment, since heating is performed by the ceramic heater 130 in the middle of the resin injection process (time T2), it is necessary to adjust the conditions so that the sealing material being injected does not harden. However, the time t5 from the start of the resin injection process to the resin curing is shorter than the time t1 + t2 until the conventional resin curing process is completed, and the shortened time t6 is the resin curing shortening of the first embodiment. Longer than time t4. This is because heating is performed by the ceramic heater 130 in the middle of the resin injecting step, so that the resin injecting time is shortened and the resin curing time is also shortened. That is, productivity can be further improved than in the first embodiment.

  Next, an example of the third embodiment of the present invention will be described. FIG. 9 shows a resin curing step in resin sealing according to this embodiment. The graph of the code | symbol H3 represents the mode of resin curing in this embodiment, and the graph of the code | symbol R represents the mode of conventional resin curing without a ceramic heater. The present embodiment is the same as the first embodiment regarding the structure of the sealing device, but the resin sealing process is different. Before describing the resin sealing step, the aim in the present embodiment will be described with reference to FIG.

  FIG. 8 shows a temperature measurement result at a position P at the center of the upper surface 136A of the cull portion 136 when the resin tablet 146 is melted at the cull portion 136 without using the ceramic heater 130. The temperature at the position P in the center of the upper surface 136A of the cull portion 136 decreases by several tens of degrees from T0 when the resin tablet 146 contacts the upper surface 136A of the cull portion 136, and it takes a considerable time to return to the original temperature. Yes. This phenomenon is considered to occur not only at the position P but also around the cull portion 136. The temperature drop around the cull portion 136 after the start of injection of the sealing material T0 is that the temperature of the resin tablet 146 to be set is room temperature and is considerably lower than the temperature of the mold 104, and the sealing material is This is thought to be caused by the loss of heat due to the latent heat of fusion when melting. In the present embodiment, the ceramic heater 130 is caused to function simultaneously with the start of the resin injecting step so as to compensate for the temperature drop around the cull portion 136. Hereinafter, the resin injection process and the resin curing process will be mainly described with reference to FIG.

  First, in a state where the plunger 144 is placed at the lower limit position in the pot 142, the resin tablet 146 is set in the pot 142, and the plunger 144 rises.

  Next, the resin tablet 146 is pumped by the rise of the plunger 144 while being melted by the heat from the mold 104 and the plunger 144, and the inside of the cavity 118 that seals the sealed product through the cull portion 136, the runner 138, and the gate 140. Injected into.

  The ceramic heater 130 is caused to function as the plunger 144 rises, and the cull portion 136 is heated for several seconds to several tens of seconds. The ceramic heater 130 is caused to function by a control unit (not shown) of the sealing device 100.

  After the function of the ceramic heater 130 is stopped, the mold is opened when the sealing material is cured, and the sealed sealed product is taken out.

  Also in this embodiment, basically, as in the second embodiment, it is necessary to adjust the conditions so that the sealing material being injected is not cured. However, by causing the ceramic heater 130 to function simultaneously with the start of the resin injection process (time T3), the time t7 from the start of the resin injection process to the resin curing is equal to the time t1 + t2 until the conventional resin curing process is completed. The shortened time t8 is shorter than the resin curing shortened time t6 of the second embodiment. This is due to the fact that the resin curing process is started at the same time as the resin injecting process, thereby shortening the resin injecting time and further shortening the resin curing time. That is, productivity can be further improved than in the second embodiment.

  In this embodiment, the case where the ceramic heater 130 is caused to function simultaneously with the start of resin injection has been described. However, the ceramic heater 130 may be caused to function before the resin injection step is started.

  Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment. That is, it goes without saying that improvements and design changes can be made without departing from the spirit of the present invention.

  In the above embodiment, the first mold is the upper mold 106 and the second mold is the lower mold 108, but the present invention is not limited to this. For example, the first mold may be a lower mold and the second mold may be an upper mold.

  In the above embodiment, the sealing material is a thermosetting resin. However, the present invention is not limited to this, and the sealing material is not limited to the resin, and may be other thermosetting materials. Absent.

DESCRIPTION OF SYMBOLS 100 ... Sealing device 102 ... Substrate 104 ... Die 106 ... Upper mold 108 ... Lower mold 110, 111 ... First upper mold 112 ... Second upper mold 118 ... Cavity 120 ... Upper cavity 122 ... Lower cavity 124 ... Air gap 126 ... Third recess 126A ... bottom surface of third recess 128 ... fourth recess 130, 131 ... ceramic heater 130A ... lower surface (contact surface) of ceramic heater
132, 133 ... heat insulating member 134 ... elastic member 136, 137 ... Cull part 136A ... upper surface of the cull part 138 ... runner 140 ... gate 142 ... pot 144 ... plunger 146 ... resin tablet

Claims (14)

In a sealing device for injecting a molten sealing material into a cavity constituted by a first mold and a second mold, and sealing an article to be sealed disposed in the cavity,
Each of the first molds is provided with a cull portion and a gap facing the cull portion and having a bottom surface formed on the cull portion side.
An elastic member that generates a pressing force on the side of the cull inside the gap;
A planar heater provided with a contact surface that is provided with the pressing force and is in thermal contact with the bottom surface;
A sealing device comprising: In claim 1,
The planar heater has a width equal to or smaller than a width of the cull portion in a direction from the cull portion to the cavity. In claim 1 or 2,
A sealing device, wherein a gap is provided between a side surface of the gap with respect to the bottom surface and at least one side surface with respect to the contact surface of the planar heater. In any one of Claims 1 thru | or 3,
The sealing device, wherein a side surface of the gap with respect to the bottom surface does not contact a side surface of the planar heater with respect to the contact surface. In any one of Claims 1 thru | or 4,
A heat insulating member is disposed between the planar heater and the elastic member. In claim 5,
A sealing device, wherein the heat insulating member is provided with a recess that fits with the planar heater. In any one of Claims 1 thru | or 6.
The planar heater is a ceramic heater. In any one of Claims 1 thru | or 7,
Watt density of the planar heater, seal and wherein the 15W / cm ² or more 55W / cm ² or less. In any one of Claims 1 thru | or 8.
The thickness of the said planar heater is 0.5 mm or more and 4 mm or less. The sealing device characterized by the above-mentioned. In any one of Claims 1 thru | or 9,
The distance between the said contact surface and the upper surface of the said cull part is 3 mm or more and 10 mm or less. The sealing device characterized by the above-mentioned. In any one of Claims 1 thru | or 10.
A sealing device comprising: means for causing the planar heater to function when injection of the molten sealing material into the cavity is completed. In any one of Claims 1 thru | or 10.
A sealing device, comprising means for causing the planar heater to function during the injection of the molten sealing material into the cavity. In any one of Claims 1 thru | or 10.
A sealing device comprising: means for causing the planar heater to function at the start of injection of the molten sealing material into the cavity or before. In a sealing method for injecting a molten sealing material into a cavity constituted by a mold and sealing an article to be sealed disposed in the cavity,
In the process from supplying the sealing material to the mold until it is cured to the required hardness in the cavity, it is opposed to the cull portion provided in the mold and pressed against the mold by an elastic member. And a step of causing the planar heater that is in thermal contact to function.

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