JP2009105273A - Resin sealing mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the cure time, and to maintain the high mobility of a resin when the resin flows. <P>SOLUTION: In the resin sealing mold 100, a substrate 130 on which a semiconductor chip 132 is loaded is clamped by upper and lower molds 102 and 104 facing each other and the substrate 130 is sealed using a resin 160 filled inside the molds. In a compression mold 108 constituting the lower mold 104, a sheet heater 140B is embedded at a position closer to the surface of the compression mold 108 than the thickness in the facing direction of the resin 160 filled inside the mold. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technical field of resin sealing in which a molded product on which a semiconductor chip or the like is mounted is sealed with resin.

  In the field of mounting electronic parts such as semiconductors, a bare chip whose circuit is designed by patterning technology such as exposure is cut out from the wafer, mounted on a die, and further connected to an external terminal by wire bonding or the like, and then sealed with resin. There is a process to stop.

  In this resin sealing process, a so-called thermosetting resin that accelerates curing by applying heat is used, but after filling the resin into the cavity, several minutes are spent on the resin curing time (cure time). There was a problem of low productivity (long cycle time).

  As a means for shortening the curing time, the resin package device shown in FIG. 10 is known (see Patent Document 1). This resin package device is a so-called transfer-type device, and in addition to the normal heater 10 provided inside the upper and lower molds disposed to face each other, the heat-absorbing and heating elements 16 and 17 are provided in the vicinity of the cull portion 12 and the cavity 14. It is comprised so that it may provide. Moreover, the heat absorption and heating elements 16 and 17 are surrounded by the heat insulators 18 and 19.

  By using the resin package apparatus having such a configuration, when the resin sealing is pushed out (when the resin flows), the calorie portion 12 and the cavity 14 are melted by the endothermic action of the heat-absorbing and heat-generating bodies 16 and 17. Since the temperature is maintained, the viscosity of the sealing resin is maintained at an appropriate value, and the extrusion speed of the resin in the cavity 14 can be maintained at an appropriate value. Further, at the time when the extrusion process is completed, the inside of the cull part 12 and the cavity 14 is heated to the curing temperature of the sealing resin by the heat radiation action of the heat-absorbing and heating elements 16 and 17, and the curing of the resin is promoted. That's it.

JP 2000-91367 A

  Generally, as the thermosetting resin as the sealing material, a glass filler mixed with epoxy is used. This sealing material has the property of increasing fluidity (decrease in viscosity) within a certain temperature range and promoting curing (increasing viscosity) at a temperature higher than that. If you only want to shorten the resin curing time (cure time), simply increase the mold temperature in advance (in order to ensure resin fluidity, higher than the temperature range where the resin has a low viscosity) ), Or by switching the mold temperature to a higher state from an earlier stage, the resin can be cured more quickly. However, setting the temperature of the mold in advance or switching the temperature of the mold from an earlier stage means that the resin is hardened at the stage of flow, and therefore other problems due to deterioration of the fluidity of the resin Problems (for example, the resin does not spread uniformly, the bonding wire or the like is cut or short-circuited due to an increase in viscosity, or a void occurs) become apparent.

  That is, as shown in FIG. 11, for example, when the temperature of the mold is set high in advance, the “time until resin curing is completed” can be shortened. There is a problem in that the time during which the fluidity of the resin is kept high is short and the resin cannot be filled well. Moreover, even if the heater installed in the mold is controlled, the heat capacity of the mold itself is large, so that the response is poor and it is difficult to change the temperature finely.

  In particular, semiconductor products used for mobile phones and the like in recent years have been made ultra-thin and finer, and the resin has low viscosity to ensure fluidity in order to perform accurate resin sealing. If the use of a low-viscosity resin is premised in this way, more time is required until curing is complete, and at the same time, techniques such as setting the mold temperature high in advance ensure fluidity. There is a problem.

  The present invention has been made to solve such problems, and shortens the time (curing time) until the curing of the resin is completed, and at the same time maintains the fluidity of the resin at the time of resin flow. An object of the present invention is to provide a resin-sealed mold that can be used.

  The present invention clamps a molded product on which a semiconductor chip is mounted with first and second molds facing each other, and seals the molded product using a resin filled in the mold. A mold, wherein at least one of the first and second molds is closer to the surface of the mold than the thickness of the resin filled in the mold in the opposing direction of the mold Further, the above-described problem is solved by arranging the first heater.

  In this way, the heater is placed in the vicinity of the mold side surface of the mold (position closer to the mold surface than the thickness of the resin filled in the mold in the opposite direction), thereby contacting the mold. It has become possible to finely control the temperature of the resin used. That is, for example, when it is desired to maintain the fluidity of the resin at a high level, the first heater is set to “a temperature range in which the fluidity can be maintained at a high level”, and immediately after the flow is completed, the temperature is set to a temperature range that promotes curing. Switch until. Here, in the present invention, a heater is laid near the surface of the mold. In recent years, considering that the thickness of the resin mold in the opposite direction (for example, the thickness of the cavity) is often less than 1 mm, the position is substantially equivalent to the surface of the mold. Because of this position, it is possible to control the temperature of the resin in real time while avoiding the influence of the heat capacity of the mold.

  Unlike the technique described in Patent Document 1, the present invention does not release accumulated heat, unlike the technique in which the heat-absorbing and heating elements 16 and 17 are provided in the vicinity of the cull portion 12 and the cavity 14. Therefore, it is possible to actively control the heating.

  Further, if the first heater is configured so as to be exposed on the mating mold side surface, the temperature of the resin can be controlled most finely.

  On the other hand, if a protective layer is formed on the opposite mold side of the first heater, it is possible to prevent the first heater disposed on the mold from being damaged by repeated resin sealing operations. it can.

  For example, by making the thickness in the facing direction of the protective layer 0.1 to 1 times the thickness in the facing direction of the resin filled in the mold, without impairing the spirit (purpose) of the present invention, It is possible to exhibit excellent protection performance.

  At this time, for example, if a heat insulating layer is formed on the opposite mold side of the first heater, the heat generated by the first heater can be more efficiently transferred to the resin side (for example, cavity, calf). , Runner side).

  For example, by making the thickness in the facing direction of the heat insulating layer 1 to 10 times the thickness in the facing direction of the resin filled in the mold, excellent heat insulating properties are secured while maintaining structural strength. It becomes possible to do. Depending on the characteristics of the material constituting the heat insulation layer, if it is less than 1 time, sufficient heat insulation effect cannot be exhibited, and if it exceeds 10 times, the structural strength of the entire mold is low. We cannot secure enough.

  Of course, the second heater is embedded in the mold in which the first heater is disposed, instead of being controlled only by the first heater disposed in the vicinity (or surface) of the mold surface. With the configuration, the role of maintaining the mold having a large heat capacity at a predetermined temperature can be entrusted to the built-in second heater, so that the first heater only takes into account the acceleration of resin curing. Design becomes possible.

  Further, at least one of the first and second molds is composed of a frame-shaped mold having a through-hole and a compression mold that can be fitted into the through-hole and slid to the mating mold side, It is advantageous in practice if the first heater is laid on the surface of the compression mold. That is, the compression mold that constitutes the first or second mold can be handled as a separate part from the frame mold that similarly constitutes the mold, and only the compression mold is processed if necessary. It is sufficient to use the conventional mold as it is for the frame-shaped mold portion. In some cases, it is only necessary to lay the first heater on the surface of the compression mold, and it is not necessary to process the compression mold itself.

  At this time, if the area in which the first heater is disposed is the same as the surface area of the compression mold, the temperature of the resin in the cavity can be uniformly controlled.

  By applying the present invention, high-quality resin sealing can be completed in a short cycle time.

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

  FIG. 1 is a schematic configuration diagram of a resin-sealed mold 100 that is an example of an embodiment of the present invention. FIG. 2 is an enlarged view centering on the heater unit 140. FIG. 3 is an enlarged view centering on the heater unit 140 and showing the relationship with the cavity thickness H1. FIG. 4 is a schematic sealing process diagram of the resin sealing mold 100. FIG. 5 is a diagram showing the relationship between the degree of cure (viscosity) of resin and time when the resin-sealed mold 100 according to the present invention is used. For ease of explanation and understanding, the drawings are partially exaggerated in scale, etc., and are not necessarily the same as the ratio of each part constituting an actual mold.

<Configuration of resin-sealed mold>
The resin-sealed mold 100 is composed of an upper mold 102 and a lower mold 104 that are arranged facing each other in the vertical direction. The upper mold 102 and the lower mold 104 are connected to a press mechanism (not shown), and can be brought into contact with and separated from each other at a predetermined timing.

  The lower mold 104 includes a frame-shaped mold 106 having a through-hole 106A that penetrates in the opposite direction, and a compression mold 108 that is fitted in the through-hole 106A and can be moved back and forth up and down. The frame-shaped mold 106 is supported from the flange portion of the compression mold 108 via a spring 110. A heater unit 140 is disposed on the surface of the compression mold 108, that is, the surface on the upper mold 102 side (details of the heater unit 140 will be described later). Further, an internal heater (cartridge heater) 108 is embedded in the compression mold 108, so that the temperature of the entire compression mold 108 can be maintained at a predetermined temperature.

  In this embodiment, the heater unit 140 is disposed only on a part of the surface of the compression mold 108. However, a configuration in which the heater unit 140 is disposed on the entire surface area of the compression mold 108 is employed. It is also possible. With such a configuration, the temperature of the resin 160 in the cavity 170 can be more uniformly controlled.

  On the other hand, a suction mechanism (not shown) is provided on the surface of the upper mold 102 (surface on the lower mold 104 side), and a substrate (molded product) 130 conveyed into the mold by a conveyance mechanism (not shown). Can be adsorbed and held.

  In addition, the code | symbol 150 in FIG. 1 is the release film (mold release) for preventing that the resin 160 as a sealing material adheres to the metal mold | die surface, or improving the mold release property of the molded product after resin sealing. Film). A space formed by clamping the substrate 130 with the upper mold 102 and the lower mold 104 is a cavity 170.

<Configuration of heater unit>
Next, the configuration of the heater unit 140 will be described. The heater unit 140 includes, for example, a sheet-like seat heater (first heater) 140B configured by an electric heater and the like, and a protective plate (protective layer) 140A disposed on the upper surface of the sheet heater 140B, that is, on the cavity 170 side. And a heat insulating layer 140C formed between the seat heater 140B and the compression mold 108 (on the upper die 102 side).

  The protection plate 140A is made of, for example, the same material as that of the compression mold 108, and has a strength that can sufficiently protect the seat heater 140B from the pressure at the time of resin sealing. That is, the protection plate 140A here is a member that constitutes the compression mold 108 itself as well as the heater unit 140. In other words, the seat heater 140B is disposed so as to be embedded in the mold by the thickness of the protective plate 140A. Further, the heat insulating layer 140C conducts heat from the seat heater 140B to the compression mold 108 side in order to efficiently guide the heat generated by the seat heater 140B to the cavity 170 side via the protective plate 140A. It is provided for the purpose of preventing. The heat insulation layer is formed of a material such as ceramic. Of course, the material of the heat insulating layer is not limited to ceramic, and heat insulating layers of various materials and structures can be used as long as the heat generated by the seat heater 140B can be effectively cut off. In addition, the heat insulating layer 140C in the present embodiment is arranged to be adjacent to the seat heater 140B, but may be separated.

  Further, as shown in FIG. 3, in the present embodiment, the thickness of the protective plate 140A (the thickness in the opposing direction of the upper mold 102 and the lower mold 104) H2 is the thickness of the cavity 170 at the completion of the compression process (upper mold). The thickness of the resin 160 filled between the lower mold 104 and the lower mold 104 in the facing direction is required to be not more than 1 times H1. That is, the seat heater 140B is disposed at a position closer to the surface of the mold than the thickness of the resin 160 filled in the mold in the opposing direction of the mold. Similarly, the thickness H3 of the heat insulating layer 140C (the thickness in the facing direction of the upper mold 102 and the lower mold 104) H3 is desirably 1 to 10 times in comparison with the thickness H1 of the cavity 170 at the completion of the compression process. This depends on the characteristics of the material constituting the heat insulation layer, but if it is less than 1 time, sufficient heat insulation effect cannot be exhibited. This is because sufficient strength cannot be secured sufficiently.

  In the present invention, these protective plate (protective layer) 140A and heat insulating layer 140C are not necessarily essential components. For example, when the seat heater 140B itself has a structure that can sufficiently withstand repeated resin sealing, the seat heater 140B may be exposed on the mold surface. The same applies to the heat insulating layer 140C. For example, when the thermal conductivity of the material itself constituting the mold is low, a structure in which the heat insulating layer is omitted is also possible.

  In the present embodiment, the seat heater 140B is laid on the surface of the compression mold 108, which is advantageous in terms of enforcement. That is, the compression mold 108 constituting the lower mold 104 can be handled as a separate part from the frame mold 106 constituting the lower mold 104, and only the compression mold 108 is processed if necessary. As a result, the conventional mold can be used as it is for the portion of the frame-shaped mold 106. In some cases, it is only necessary to lay the seat heater 104B on the surface of the compression mold 108, and it is not necessary to process the compression mold 108 itself.

<Operation of resin-sealed mold>
Next, a resin sealing process using the resin sealing mold 100 will be briefly described with reference to FIG.

  As shown in FIG. 4A, the upper mold 102 and the lower mold 104 are initially separated from each other. In this state, the substrate 130 having the semiconductor chip 132 mounted on the surface of the upper mold 102 is conveyed and sucked and held by a conveyance mechanism (not shown). On the other hand, a resin 160 as a sealing material is poured into the cavity 170 of the lower mold 104 (the portion where the step between the frame-shaped mold 106 and the compression mold 108 is formed) by a transport mechanism (not shown) ( More precisely, since the release film 150 is adsorbed and held on the surface of the lower mold 104, it is put on the release film 150). In this embodiment, the resin 160 is a preform resin preliminarily molded into a predetermined shape. Of course, it is not limited to the preform resin in this way, and various forms of resin such as powder, granule, and pellet may be used.

  At this time, the temperature of the entire compression mold 108 is maintained within a predetermined temperature range (a temperature range in which the flowability of the charged resin 160 is high) by an internal heater 108A provided in the compression mold 108. Has been. As a result, at the same time as the resin 160 is charged into the cavity 170, the resin starts to melt and the fluidity is improved. On the other hand, the seat heater 140B (heater unit 140) disposed in the compression mold 108 is not operating.

  Next, as shown in FIG. 4B, the upper mold 102 and the lower mold 104 come into contact with each other. By this operation, the resin 160 put into the cavity 170 is compressed, and the cavity 170 is uniformly filled (compression process). At this point in time, the seat heater 140B (heater unit 140) disposed in the compression mold 108 is not operating, and the fluidity of the resin 160 is exclusively due to the internal heater 108A provided inside the compression mold 108. The mold temperature is maintained in a high temperature range. As a result, the flow of the resin 160 does not induce a short circuit / cut of a bonding wire or the like provided on a semiconductor chip or the like, and the resin 160 is uniformly filled into the cavity 170 due to its high fluidity. It is possible to make it.

  Subsequently, as shown in FIG. 4C, when the compression process by the compression mold 108 is completed (or before and after), the seat heater 140B (heater unit 140) disposed in the compression mold 108 operates. Then, the temperature of the resin 160 filled in the cavity 170 is heated to a curing temperature range at a stretch. As described above, the seat heater 140B (heater unit 140) in the present embodiment is disposed on the surface of the compression mold 108 via only the protective plate 140A, and can quickly change the temperature of the resin 160. . Further, since the heat insulating layer 140C is provided under the seat heater 140B, the heat generated in the seat heater 140B (heater unit 140) can be efficiently passed into the cavity 170 without escaping to the entire compression mold 108. To the side of the resin 160 filled in the.

  Note that the time when the operation of the seat heater 140B is not necessarily required to be the same as the completion of the compression process. For example, control is performed so as to operate in a certain temperature range (for example, a temperature range in which the resin fluidity is high) before the compression process ends, and to switch the temperature simultaneously with (or before and after) the compression process ends. Also good.

  FIG. 5 shows the relationship between the degree of cure (viscosity) of resin and time when resin sealing is performed by such a process. As shown in FIG. 5, when resin sealing is performed using the resin sealing mold 100 to which the present invention is applied, the degree of curing of the resin rapidly increases as soon as the compression process is completed. ing. That is, until the compression process is completed, the fluidity of the resin as the resin material is kept high, and at the same time, the resin is quickly cured at the stage where the resin flow is finished, and the time until the resin is completely cured (Cure time) is shortened. As a result, it is possible to complete the resin sealing in a short cycle time while maintaining a high resin sealing quality by uniformly filling the cavity with the resin in a state where the resin fluidity is high.

  Further, when shifting to the next sealing operation, it is necessary to lower the temperature around the cavity 170 to a temperature range where the resin fluidity is high. In the present embodiment, since the sheet heater 140B is disposed on the surface of the mold only through the protective plate 140A, for example, the temperature is simply and quickly lowered by applying air to the mold surface with a blower or the like. Can be made.

<About another embodiment of the present invention>
Further, in the above embodiment, the heater unit 140 is provided only on the compression mold side 108 constituting the lower mold 104, but a configuration provided on the upper mold 102 side may be adopted. For example, as shown in FIG. 6, the heater unit 240 </ b> A is laid on the surface of the compression mold 208, and at the same time, the heater unit 240 </ b> B is similarly laid on the surface of the upper mold 202 side on which the substrate 230 is sucked and fixed. It may be adopted. In this way, it is possible to control the temperature of the substrate 230 as the molded product from the vertical direction in a more uniform state, and to prevent “warping” of the substrate 230 after sealing. In this case, the heater unit 240B laid on the upper mold 202 side need not have the same configuration as the heater unit 240A provided on the compression mold 208 side. That is, as in this embodiment, when the upper mold 202 is not in direct contact with the resin as the sealing material but is in contact with the substrate 230, the size and set temperature of the heater unit 240B are appropriately set. Can be changed and adjusted.

  Further, as shown in FIG. 7, the heater unit 440 disposed in the compression mold 408 may be configured to be detachable via an insert 408A, for example. With such a configuration, it becomes easy to appropriately replace heater units having different performances.

<Application example to transfer system>
In the above description, the so-called “compression mold” is described as an example. However, the present invention can be widely applied to transfer type resin-sealed molds. FIG. 8 and FIG. 9 show application examples to a transfer mold.

  When applied to a transfer mold, not only the cavity but also the first heater (for example, a seat heater) is disposed at a position corresponding to the cull part or the runner part, so that the cull part or the runner part flows. The temperature of the resin and the staying resin can be positively managed. In the example shown in FIGS. 8 and 9, first heaters (local heaters) 46 and 546 are disposed on or near the surfaces of the cull portions 36 and 536. With such a configuration, in the curing process, the resin existing in the cull portions 36 and 536 having a thickness (A2) in the resin is more actively cured, thereby aligning the curing timing with the runner portion 50 and the like. Is possible. In this case, the positions of the first heaters (local heaters) 46 and 546 from the mold surface are the thicknesses of the resin filled in the positions corresponding to the first heaters (local heaters) 46 and 546 (that is, What is necessary is just to arrange | position to the position nearer to the mold surface than the cull portions 36 and 536 (thickness A2).

  The present invention can be widely applied to a resin molding die using a thermosetting resin.

Schematic configuration diagram of a resin-sealed mold that is an example of an embodiment of the present invention Enlarged view centering on the heater unit An enlarged view centered on the heater unit, showing the relationship with the cavity thickness Schematic sealing process diagram of resin-sealed mold that is an example of an embodiment of the present invention The figure which showed the relationship between the hardening degree (viscosity) of resin at the time of using the resin sealing metal mold | die concerning this invention, and time The figure which showed the 2nd Embodiment of this invention The figure which showed the 3rd Embodiment of this invention The figure which showed the 4th Embodiment of this invention The figure which showed the 5th Embodiment of this invention Resin package device described in Patent Document 1 Figure showing the relationship between the degree of cure (viscosity) of resin and time

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Resin sealing mold 102 ... Upper mold 104 ... Lower mold 106 ... Frame-shaped mold 106A ... Through-hole 108 ... Compression mold 108A ... Internal heater 110 ... Spring 130 ... Substrate (molded article)
132 ... Semiconductor chip 140 ... Heater unit 140A ... Protection plate (protection layer)
140B ... Heater 140C ... Heat insulation layer 150 ... Release film 160 ... Resin (sealing resin)
170 ... cavity

Claims (9)

A resin-sealed mold that clamps a molded product on which a semiconductor chip is mounted with opposing first and second molds and seals the molded product using a resin filled in the mold. And
At least one of the first and second molds has a first heater at a position closer to the mold surface than the thickness of the resin filled in the mold in the opposing direction of the mold. A resin-sealed mold characterized in that is disposed. In claim 1,
The first heater is exposed on the surface of the mating mold. A resin-sealed mold. In claim 1,
A resin-sealed mold, wherein a protective layer is formed on the mold side of the first heater. In claim 3,
The resin-sealing mold, wherein the thickness of the protective layer in the facing direction is 0.1 to 1 times the thickness in the facing direction of the resin filled in the mold. In any one of Claims 1 thru | or 4,
A resin-sealed mold, wherein a heat insulating layer is formed on the opposite mold side of the first heater. In claim 5,
The resin-sealing mold, wherein the thickness of the heat insulating layer in the facing direction is 1 to 10 times the thickness of the resin in the facing direction filled in the mold. The resin-sealed mold according to any one of claims 1 to 6, wherein a second heater is embedded in a mold in which the first heater is disposed. In any one of Claims 1 thru | or 7,
At least one of the first and second molds is composed of a frame-shaped mold having a through-hole and a compression mold that can be fitted into the through-hole and slidable on the counterpart mold side,
The first heater is disposed in the compression mold. A resin-sealed mold. In claim 8,
The area where the first heater is disposed is the same as the surface area of the compression mold.

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