JP2006088619A - Seal-molding apparatus and manufacturing method for resin-sealed semiconductor package using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal-molding apparatus which can obtain a resin-sealed semiconductor package which is hard to cause wire flow even when fine-line wires are formed, and a manufacturing method for a resin-sealed semiconductor package using it. <P>SOLUTION: The seal-molding apparatus having a mold clamping mechanism and a molding plunger advancing/retracting mechanism. The seal-molding apparatus has: a bottom mold 1 having a resin receiving part 7 for receiving a sealing resin formed at the upper part of the tip end face 3a in a bottom mold cavity section 4 in the state of the molding plunger 3 being retracted and loaded with a molding plunger 3 for compression molding movably back and forth so as to compress a sealing resin fed to the resin receiving part by the tip end face to constitute a bottom molding surface of the bottom mold cavity for molding in the state of the molding plunger 3 being advanced; a mold composed of this bottom mold 1 and a top mold 2 capable of being clamped by the mold clamping mechanism 6; and a resin feeder 20 which feeds an agitated-melted resin MR for sealing to the above resin receiving part 7 in the state of this mold being opened. The area of the tip end surface 3a of this molding plunger 3 is at least 90% to the area of the bottom molding surface of the bottom mold cavity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sealing molding apparatus for manufacturing a resin-encapsulated semiconductor package in which semiconductor devices such as transistors and ICs are encapsulated with resin, and a method for manufacturing a resin-encapsulated semiconductor package using the same.

  A transfer mold apparatus is used as a method for efficiently molding a resin-encapsulated semiconductor package (so-called package or resin-encapsulated semiconductor device) by encapsulating a semiconductor device (semiconductor chip) such as a transistor, IC, or LSI with resin. Transfer molding is widely used (for example, Patent Document 1).

  This method involves heating and melting an uncured resin (hereinafter simply referred to as a resin) such as an epoxy molding material mainly composed of an epoxy resin and a filler, and injecting it into a mold using a transfer molding machine. For example, a semiconductor chip mounted on a lead frame or a tape substrate is sealed by molding and curing in a high temperature and high pressure state.

  The resin-encapsulated semiconductor device (resin-encapsulated semiconductor package) manufactured by this method is excellent in reliability because the epoxy resin composition is completely covered with the semiconductor chip, and is densely molded with a mold. Since the appearance of the package is also good, most of the resin-encapsulated semiconductor devices are currently manufactured by this method.

  In molding by this transfer mold apparatus, a tablet of a thermosetting resin to be sealed is put in a pot, and the resin received in the pot is fed to the mold cavity while being melted. Curing is performed in a state where the sealing resin is sufficiently filled in the mold cavity portion, and the resin-encapsulated semiconductor package is molded.

  In contrast, a sealing resin sheet made of an uncured resin is disposed on at least the active surface side of the semiconductor chip connected to the external lead structure via the bonding wire, and the sealing resin sheet is disposed on the semiconductor chip. A method for manufacturing a resin-encapsulated semiconductor device including a sealing step in which a semiconductor chip is sealed by being cured while being pressed (hereinafter, this may be abbreviated as a compression molding method) has been proposed. (For example, Patent Document 2).

  Further, when the sheet-like resin R is directly molded in the cavity, as shown in FIG. 15, molding plungers 3 and 3 ′ are arranged in the lower mold 1 and the upper mold 2, and compression molding is performed by the molding plungers 3 and 3 ′. A method has been proposed (for example, Patent Document 3). Moreover, as shown in FIG. 16, this plunger 3 may be provided only in the lower mold | type 1. FIG.

  The cavity molding portion 4 of the lower mold 1 is slidably provided with a molding plunger 3 whose bottom surface is the tip surface 3a. Further, a molding plunger 3 ′ is slidably provided on the cavity molding portion 4 of the upper mold 2 so that the upper bottom surface of the cavity becomes the tip surface 3 a ′.

  In such an apparatus, the sheet-like resin SR is placed on and put into the upper surface of the lead frame F and the cavity molding portion 4 of the lower mold 1, respectively. The sheet-shaped resin SR starts to melt as soon as it comes into contact with the upper mold 2 and the lower mold 1. When the sheet-shaped resin SR is put into the lower mold 1, the upper mold 2 continues to descend together with the lead frame F, clamps the lead frame F with the lower mold 1, and clamps the upper mold simultaneously with completion of the mold clamping. The molding plunger 3 'in 3 is lowered (retracted) to a predetermined position and stopped. Next, the molding plunger 3 in the lower mold 1 is raised (advanced) and the resin is compression-molded to obtain the resin-encapsulated semiconductor package P in which the semiconductor device H of the lead frame F is sealed with the resin. .

According to such a compression molding method, the sealing process can be automated and inlined, and it is suitable for increasing the size and thickness of the package, meeting the requirements for high package accuracy and high package reliability. It has been proposed that it can be used as a method for manufacturing a corresponding resin-encapsulated semiconductor device.
JP-A-8-111465 (prior art column and FIG. 19) JP-A-6-275767 (FIGS. 10 and 11) JP-A-8-330342 (FIGS. 13 and 14)

  However, according to the transfer molding apparatus described in Patent Document 1, a considerable portion of the resin tablet made of an expensive resin material is discarded as an unnecessary cured resin. Moreover, since the resin tablet is originally manufactured on the assumption that it is used as a sealing resin, the cured resin to be discarded also has a high quality sufficient to satisfy the requirements for the sealing resin. Therefore, high-quality resin is discarded, and there is a problem from the viewpoint of not only cost but also effective use of resources.

  In addition, the cull portion and the runner portion are designed according to the size (outer diameter) of the resin tablet. Therefore, there is a certain limit even if an attempt is made to improve the resin yield (ratio of the resin used as the sealing resin to the used tablet resin) for the resin tablet to reduce the discarded portion.

  Moreover, according to such a transfer molding apparatus, a resin tablet having a different size must be used every time the size of the mold cavity is different. Thereby, it is necessary to stock a plurality of types of resin tablets, and the inventory management of the resin tablets becomes complicated.

  In addition, it is necessary to prepare a transporting and loading mechanism corresponding to each size of such a resin tablet, which hinders downsizing of the resin sealing device and simplification of the mechanism.

  On the other hand, according to the compression molding method described in Patent Document 2 and Patent Document 3, since the cull, runner, and gate are not required, the amount of waste resin of the unnecessary resin based on the cal resin or the like is eliminated. Further, since the cull part, the runner part, and the gate part are not required, the mold and the entire apparatus can be made compact.

  However, in recent years, with the increase in size of semiconductor chips due to the high integration of resin-encapsulated semiconductor devices, the size of packages for resin-encapsulated semiconductor devices has also increased, while the packaging space has been miniaturized. Wires are becoming thinner and more dense, and this trend is expected to become stronger in the future.

  Here, according to the conventional compression molding method, there is a problem that a wire flow occurs. Thus, a highly reliable sealing molding apparatus or a method for manufacturing a resin-encapsulated semiconductor package that can cope with a case where the wire is further thinned has not been proposed. In particular, when the resin-encapsulated semiconductor package is thinned and a semi-hard gold wire having a wire diameter of about 20 μm and a length of several millimeters is used, the bonding wire is deformed and contact with the adjacent bonding wire occurs. Cheap. This problem is also a problem in the case where a so-called inner lead bonding method in which electrical connection with a chip is directly made at the tip of a lead such as a film carrier via a bump or the like.

  Under such circumstances, the present applicant has previously made a sealing molding apparatus that can obtain a resin-sealed semiconductor package in which wire flow hardly occurs even when the wire is thinned, and sealing molding using the same. A patent application has already been filed for a method for producing a body (see Japanese Patent Application No. 2003-89640 filed on Mar. 28, 2003).

  According to this application, a sealing molding apparatus having a mold clamping mechanism and a molding plunger advance / retreat mechanism has been proposed. In this sealing molding apparatus, the lower mold cavity portion is formed with a resin receiving portion for receiving the sealing resin at the upper portion of the tip surface in a state where the molding plunger is retracted, and the tip surface is resin in a state where the molding plunger is advanced. A lower mold in which a molding plunger for compression molding that forms and forms the bottom molding surface of the lower mold cavity while compressing the sealing resin supplied to the receiving portion is removably loaded, and the lower mold and the mold clamping mechanism And a resin supply device for supplying the resin for agitation and stirring to the resin receiving portion in a state where the mold is opened.

  The sealing molding apparatus according to such a prior invention has a feature that a sealed molded body is obtained in which the wire flow hardly occurs even when the wire is thinned. Moreover, according to the sealing molding apparatus which concerns on such prior application invention, the process of shape | molding a resin tablet becomes unnecessary. Moreover, the sealing molding apparatus can be reduced in size and simplified, and the amount of high-quality resin discarded can be reduced. As a result, the manufacturing cost can be reduced and the resin can be effectively used. The sealing molding apparatus and the manufacturing method of the sealing molding using the same can be provided.

  Here, an object of the present invention is to further effectively and effectively improve the sealing molding apparatus according to the above-described prior invention.

  According to the researches of the present inventors, even when the tip surface of the molding plunger is, for example, a circular shape that is easy to design, the effect of the invention of the prior application can be obtained, but the shape of the tip surface and the shape of the bottom molding surface It has been found that a resin-encapsulated semiconductor package with reduced unfilled, external voids, internal voids, wire flow, and resin disposal rate can be obtained by making them as identical as possible.

  In addition, since the tip surface of the molding plunger may be slightly smaller than the bottom molding surface, it is necessary to design it so that the ideal tip surface shape is substantially similar to the bottom molding surface. Is preferred. Here, the substantially similar shape includes the similar shape, and further includes, for example, an improved design such as providing a curvature in the shape of the corner portion.

  Further, according to the study by the present inventors, when the area of the molding plunger is 90% or more of the area of the bottom molding surface of the lower mold cavity, there is no wire flow, and It was found that unfilled, external voids, internal voids, and resin disposal rate can be reduced.

  That is, according to the first aspect of the invention, the outer shape of the tip surface of the molding plunger is designed to be substantially similar to the shape of the bottom molding surface of the lower mold cavity, which is smaller within the range of 0.1 to 0.5 mm. It is characterized by being.

  In addition, the second invention is characterized in that the area of the tip surface of the molding plunger is 90% or more with respect to the area of the bottom molding surface of the lower mold cavity.

  According to such a sealing molding apparatus, (a) a resin supply step of supplying a sealing resin in a state where the resin is stirred and melted in a state where the mold is opened, and (b) a mold clamping mechanism (C) Compression that raises the tip surface of the molding plunger to the molding surface and seals and cures the semiconductor device with the molten resin received in the resin receiving portion. A method for manufacturing a resin-encapsulated semiconductor package comprising sequentially performing a molding step and (d) a demolding step of opening a mold and taking out the obtained resin-encapsulated semiconductor package.

  In addition, according to the method for manufacturing a resin-sealed semiconductor package using such a sealing molding apparatus, the amount of resin used can be reduced because there is less wire flow and no need for cull, runner and gate. In addition, it is possible to make the mold compact and the equipment compact, and further reduce the cost.

  Further, according to the present invention, since the resin supplied to the mold is melted by stirring, the preheating time in the mold can be reduced and the production cycle can be improved.

  In addition, the sealing resin supplied to the resin supply device may be in the form of powder or granule, and does not need to be in the form of a sheet or resin tablet. There is no need for inventory management when using resin tablets.

  In addition, the bottom surface of the resin-encapsulated semiconductor package obtained as described above has an uneven line along the outer shape of the tip surface of the molded plunger. If dicing is performed within the frame of the uneven line, the performance of the molded product Does not directly affect the appearance.

  According to this invention, the flow direction of the molten resin in the sealing member is a direction substantially perpendicular to the sealing member, and is caused by the fact that the resin is uniformly melted and the amount of resin to flow is small. In addition, the flow rate of the molten resin around the sealing member may be slow, and no wire flow occurs even if the sealing member is loaded with the fine wire of the wire, and after the resin is received in the mold Providing a practically beneficial effect of providing a sealing molding apparatus capable of shortening the preheating process time, shortening the molding cycle, drastically reducing the amount of resin waste, and a method for producing a resin-sealed semiconductor package using the sealing molding apparatus. Demonstrate.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated about the same or equivalent site | part member as the sealing molding apparatus demonstrated by the prior art.

  FIG. 1 is a plan view for explaining a lower mold cavity block as a lower mold used in a sealing molding apparatus according to an embodiment of the present invention, and FIG. 2 is a cross section taken along line XX of FIG. FIG.

  In these figures, reference numeral 1 denotes a lower mold cavity block that is replaceable with respect to the lower mold or a lower mold, and a cavity molding part (mold part) 4 as a product molding part is provided at the center. The bottom surface 4a of the mold part 4 has the same rectangular shape as the bottom surface shape of the resin-encapsulated semiconductor package, and the outline of the bottom surface 4a is indicated by reference numeral 4ab.

  A central portion is penetrated in a cylindrical shape substantially similar to the bottom surface 4a, leaving a bottom surface 4a having a width w of 0.1 mm to 0.5 mm formed in a fringe shape around the inner wall of the through portion 5 A molding plunger 3 that is slidably contacted and movable up and down is loaded.

  As a result, the shape of the distal end surface 3a of the molded plunger 3 surrounded by the outer shape line indicated by reference numeral 3ab is substantially similar to the outer shape of the bottom surface 4a, and the outer shape of the bottom surface 4a indicated by the outer shape line 4ab. Designed smaller than.

  Here, in contrast to the area 100 of the bottom surface surrounded by the outline 4ab, in the present invention, the area of the front end surface 3a surrounded by the outline 3ab needs to be 90 or more. When the area ratio is 90% or more, the yield of the wire flow is dramatically improved. A preferable range of this area ratio is 93% or more, and particularly preferably 95% or more. The upper limit of the area ratio is not particularly specified, but is about 98% in design.

  Thereby, when the front end surface 3a of the molding plunger 3 has the same height as the bottom surface 4a, the lower mold cavity portion becomes equal to the mold portion 4. In addition, although uneven lines are formed on the bottom of the molded product according to the weight variation of the amount of resin received, this uneven line is unlikely to cause a problem in practical use. it can. Further, in a package such as batch molding, there is no problem in appearance if dicing is performed within the frame of the concavo-convex lines when it is divided (diced) individually after molding.

  The molding plunger 3 can be advanced and retracted by an advancing and retracting mechanism 6 for compression molding. The advance / retreat mechanism 6 is not particularly limited. For example, a mechanism that can accurately control the advance / retreat amount by a servo motor, an encoder, or the like is used. The ball screw is rotated by a timing belt or the like under the control of a servo motor (not shown) to convert the rotation of the servo motor into a vertical movement. The position of the front end surface 3a of the molding plunger 3 can be moved back and forth to a desired position while the position of the servo motor is controlled by an encoder.

  Here, “for compression molding” means an advancing / retreating mechanism capable of holding the pressure necessary for compression molding. When the pressure needs to be controlled, a pressure sensor such as a pressure sensor is provided at an arbitrary position. It is assumed that a mechanism capable of controlling the molding pressure is provided. Such a pressure control mechanism is known, and for example, a pressure detector such as a load cell is interposed between the molding plunger 3 and the advance / retreat mechanism 6 to maintain a necessary pressure by the pressure detected by the pressure detector. Can do.

  The resin receiving portion 7 for receiving the resin is formed on the front end surface 3a by retreating the position of the front end surface 3a of the molding plunger 3 from the position of the lower surface 4a of the mold portion 4 (hereinafter referred to as a mold alignment position). In FIG. 2, the molding plunger 3 is retracted, and the resin receiving portion 7 is formed on the distal end surface 3a.

  Here, in the present invention, a predetermined amount of sealing resin melted with stirring is supplied to the resin receiving portion 7.

  The sealing resin used in the present invention is not particularly limited, but is supplied in a heated and agitated state in the resin supply device, so that the thermal stability in the heated injection unit or cylinder is good. It is preferable that the fluidity is particularly good in the mold part 4 and it is hardened quickly. Such a sealing resin is known, for example, an epoxy resin, a phenol resin curing agent, as disclosed in JP-A-8-67741, JP-A-8-67742, JP-A-8-67745, An example is an epoxy resin sealing material containing a curing accelerator and an inorganic filler as essential components. As such a sealing resin, a powder or granular resin can be used as it is.

  The sealing resin can be supplied by an injection device (or injection unit) of an injection molding apparatus developed for sealing such a sealing resin (thermosetting resin) by injection molding. Such an injection device supplies, for example, a powdery or granular epoxy resin sealing material disclosed in JP-A-2002-210778, uniformly kneads and melts it with a screw mechanism, and is clamped with a clamping unit. It is an injection unit that can be moved forward and backward with respect to the mold. In addition, a screw in-line injection unit described in JP-A No. 2001-189333 and a powdery or granular epoxy resin sealing material disclosed in JP-A No. 2000-68416 are supplied and uniformly mixed with a screw mechanism. It may be an injection unit that is melted and injected into the cavity with a screw or a plunger. The screw in-line type is preferable from the viewpoint of easy temperature control and uniform melting.

  In the present invention, the resin supply device is basically an injection device (or injection unit) provided with a stirring device such as a screw type or an inline screw type, and an injection device (or an extrusion device) such as a heating device and a plunger type. I just need it. In the injection molding apparatus, the injection speed is limited due to the problem of the flow of the sealing resin. However, according to the present invention, this injection speed is not particularly limited. It is only necessary that the resin stirred by injection can be supplied to the mold.

  In this invention, the sealing resin is preferably uniformly stirred and melted. For this reason, in the present invention, a resin supply device including a heating device, a stirring device, and an injection device is preferably used. The resin that has been stirred and melted is in a low-viscous flow state in which a solid resin material such as powder or granules is melted by heating and stirring.

  When the viscosity of the supplied resin is high, if the molding cycle is accelerated, the bonding wire on the semiconductor element may be deformed or cut, or the electrical performance of the internal element may be deteriorated in a diode or the like. . On the other hand, although there is no lower limit to the viscosity of the resin to be supplied, it indicates that the lower limit of the viscosity when heated to 80 ° C. to 120 ° C. with a resin that provides necessary sealing performance is about this level.

  In the present invention, by supplying heated resin to the mold, it is possible to shorten the molding cycle and improve productivity. Moreover, in this invention, the resin which became the low-viscosity fluid state which a wire flow etc. cannot generate | occur | produce can be supplied to a metal mold | die. A suitable example of such a resin supply apparatus is described in detail in Japanese Patent Laid-Open No. 2001-341155.

  This resin supply device is, for example, a measuring unit that allows a predetermined amount of resin material to be loaded in each measuring pot arranged below via measuring means in which a screw is inserted into a measuring tube under the hopper that stores the resin material. And a stirring rod from the tip through a stirring means in which a plunger is inserted into a stirring cup that has transferred resin material between the arranged measuring pots and a plurality of stirring cups arranged in parallel with the pot. The stirring unit that enables stirring by the rotation of each protruding plunger, and the stirring unit between the measuring unit and the molding die via a moving means provided with a pulley and a belt that are attached to a motor that can move forward and backward. The resin material in the stirring cup is transferred to the mold pot of the molding die via a moving unit that can move forward and backward, and a vertical movement means that is provided with a pulley and belt that are attached to a motor that can move forward and backward. Towards, and a possible and the supply unit extrusion feed in the plunger.

  Here, in this invention, it replaces with the shaping | molding die provided with the metal mold pot, and the compression molding apparatus which made the molding surface the front end surface 3a of a plunger and provided the resin receiving part 7 on the front end surface 3a is used. After the heated and stirred resin is received in the resin receiving portion 7, the mold is clamped, and the molding plunger 3 is heated to a predetermined position to be heated and cured to complete the molding. There is provided a molding method in which a wire flow hardly occurs as compared with a compression molding method in which a conventional sheet-like resin is introduced.

  Here, if the compression molding apparatus or the resin receiving unit 7 can be provided to the supply unit by a moving unit or the like, the moving unit described in JP-A-2001-341155 is not necessary. Such a compression molding apparatus or lower mold can be incorporated in a line of a semiconductor manufacturing apparatus by using a turntable, a moving unit that can move forward and backward, a moving unit that flows in one direction, and the like. Of course, in the present invention, the resin supply device and the resin receiving portion 7 may be fixed to each other.

  Hereinafter, a sealing molding apparatus and a method for manufacturing a resin-encapsulated semiconductor package that supply and mold the agitated resin to the lower mold cavity block 1 using the resin material supply apparatus will be described.

  For example, as shown in FIG. 3, the sealing molding apparatus 20 includes a weighing unit 21, a stirring unit 31, a supply unit 41, and a moving unit 51. The details of the weighing unit 21 are shown in FIG. 4. Details of the stirring unit 31 are shown in FIG. 5, and details of the supply unit 41 are shown in FIG.

As shown in FIG. 3, the sealing and molding apparatus 20 guides the resin material R stored in the hopper 22 into the measuring tube 24a by rotating the screw 24, and measures the resin material R in the tube 24a by the screw rotational speed. Plunger in which the weighing unit 21 to be loaded in the weighing pot 25 and the weighed resin material R are exchanged between the weighing pot 25 and the stirring cup 32, and the stirring bar 33a protrudes from the tip of the stirring cup 32 The agitation unit 31 for inserting and rotating 37 and stirring and melting, the moving unit 51 for moving toward the molding die (lower die) 61 while operating the agitation unit 31, and the agitation unit 31 are moved. The plunge attached to the agitation unit 31 when the agitation cup 32 is positioned on the resin receiving part 7 of the lower die block 1 that is set to be exchangeable with the lower die 61 37 is operated, and the resin material melted in stirred cup 32, and a supply unit 41 for supplying the resin receiving part 7. Hereinafter, it demonstrates along the flow of resin.
(A) Resin supply step The powdery or granular resin material R supplied to the measuring unit 21A of the measuring unit 21 is operated by the stirring unit 31, the moving unit 51, and the supplying unit 41, respectively. A predetermined amount is supplied to the lower mold 61 in a state of being stirred and melted.

  In the weighing unit 21, as shown in FIG. 4, the resin material R supplied to the hopper 22 is moved around the screw 24 rotated by the operation of the weighing motor 23 in the hopper 22. The breaking pin 22c also rotates to break the resin material R without bridging, and is easily fed into the screw 24 and supplied. The screw 24 measures a predetermined amount at a predetermined rotation speed in the measuring tube 24a and is loaded from the measuring unit 21A into the measuring pot 25 of the pot unit 25A.

  By the operation of the feeding motor 27, the measuring unit 21A loads all the measuring pots 25 with the resin material R while moving on each measuring pot upper end surface 25a.

  When each measuring pot 25 is loaded, the pot moving cylinder 28 is operated, the pot portion 25A is moved to the right, the cup moving motor 33 is also operated, and the stirring cup 32 is greeted to the left. Then, the cylinder 26 for opening and closing is operated under the weighing pot 25 to open the shutter plate 26a, and the measured resin material R is transferred. Then, it moves so as to return to the right and is positioned under the plunger 37.

  Next, the four stirring rod cylinders 36a are operated to cause the stirring rod 37a to protrude from the tip of the plunger 37, and then the stirring motor 38 having the gear 38a mounted on the shaft is operated. The plunger 37 is rotated through the gears 38b, and the resin material R in the stirring cup 32 is stirred and melted. Here, the temperature of the stirring cup 32 is appropriately set depending on the resin material R to be used, but is most commonly heated within a range of 80 ° C to 120 ° C.

  In the stirring unit 31, as shown in FIG. 5, while moving, the moving motor 52 of the moving unit 51 is quickly operated to move the timing belt 54 forward and to the position where the limit switch 56a is braked. .

  When the stirring and melting are finished, the stirring cylinder 36a is operated to raise the movable plate 44, and the stirring rod 37a is drawn into the cylinder 37 and buried.

  And in the stop position of the stirring unit 31, the supply unit 41 (FIG. 6) integrated in this stirring unit 31 is operated.

  That is, by operating the vertical movement motor 45 and rotating the ball screw 42 through the shaft-attached pulley 45a and belt 45b, each ball screw nut 43 is mounted by the lower connecting plate 36. The plunger 37 is lowered at a stroke, and the molten resin MR melted in the stirring cup 32 is supplied to the resin receiving portion 7 provided in the lower mold 61.

  The temperature of the molten resin MR supplied to the resin receiving portion 7 varies depending on the type of the resin material R to be used, but the most general case where the mold temperature is 170 ° C. to 180 ° C. (for example, about 175 ° C.). The viscosity is in the range of 80 ° C. to 120 ° C., which is substantially the same as the temperature of the stirring pot 32, and the viscosity at that time is in the range of approximately 50 Pa · s to 350 Pa · s. Further, since this resin is stirred, homogenized, and low in viscosity, the molten resin MR supplied to the resin receiving portion 7 is rapidly heated in the plane direction while being further heated at the mold temperature ( FIG. 7).

On the other hand, in this embodiment, the agitating unit 31 that has been supplied is moved by the reverse rotation of the moving motor 52, moves the timing belt 54 backward, and stops when the limit switch 56a is braked. It moves toward the back to the position of the pot portion 25A and prepares for the next resin supply step.
(B) Mold Clamping Step Next, the preheated lead frame F is positioned on the mold part 4 via an inloader for collecting, aligning and unloading the lead frame (not shown) and loaded onto the lower mold surface 1a (FIG. 7). ). Here, in this embodiment, a CSP holding the semiconductor device H on one side of the plastic film F is used, and the plastic film F is loaded with the surface to be sealed facing the lower surface. The mold is closed by a mold clamping mechanism that raises and lowers at least one of the upper mold 2 or the lower mold 1 (FIG. 8).
(C) Compression molding step Next, as shown in FIG. 9, compression molding is performed while driving the advance / retreat mechanism 6 to raise (advance) the front end surface 3 a of the molding plunger 3 to the mold alignment position (molding surface). Thereby, the molten resin MR supplied to the resin receiving portion 7 flows toward the mold portion 4. Since the temperature of the mold is set at 180 ° C., when the resin temperature reaches 175 ° C., the viscosity of the molten resin MR further decreases to, for example, 3 to 20 Pa · s.

  Moreover, since the direction of the flow of the molten resin MR is sealed from below the semiconductor device H to be sealed, in a sealing member such as a CSP, the distance of the molten resin that moves in the sealing member including the wire W Therefore, since the flow rate of the molten resin MR across the wire W is slow, the wire flow is less likely to occur even when the wire W is thinned. Thereby, the semiconductor device H can be sealed with the molten resin MR without causing a wire flow. By maintaining this state for a predetermined time (for example, several seconds to several tens of seconds), the sealing resin is cured by heat.

  Here, these mold temperatures, pressures and holding times vary depending on the performance of the resin used, the size of the mold, the size of the package, etc., so the optimum conditions are appropriately determined by experiments and the like, and the temperature, pressure, The curing holding time and the like are not limited to the above example.

  According to such a device, the compression-molded resin-encapsulated semiconductor package (product P) has a surface 3a ′ molded by the molding plunger 3 in the lower mold 1 that moves up and down due to resin amount variation. A substantially square concave or convex concave / convex mark 3ab ′ is formed along the outline 3ab of the distal end surface 3a of the plunger 3 (FIG. 10).

  Here, in this embodiment, the outer shape of the distal end surface 3a of the plunger 3 is designed to be slightly smaller than the outer shape of the bottom surface 4a of the cavity portion 4 within a range of 0.1 mm to 0.5 mm. The mark 3ab 'is formed in a fringe shape on the periphery of the semiconductor device if the variation in the weight of the resin to be loaded is about ± 0.1 g, for example, and does not substantially affect the performance of the product.

In a package such as CSP, BGA or the like (collectively called MAP), dicing is individually performed within the frame of the concave / convex mark 3ab ′ after demolding. As a result, the uneven mark 3ab ′ is not reflected on the bottom surface of the product.
(D) Demolding process After the curing is completed, the upper and lower molds (molds) are opened by a mold clamping mechanism, and the product P as a resin-encapsulated semiconductor package is taken out by an arbitrary technique. In order to take out the product P, for example, a suction device such as a suction cup is used, but it may be taken out using a knockout pin or an ejector plate. Further, if the plunger 3 can be protruded from the mold part 4, the plunger 3 can be easily taken out even if the side surface 4 b of the mold part 4 has no opening gradient.

  In addition, as shown in FIG. 11, the product P can be taken out by lowering (retracting) the plunger 3 by the advance / retreat mechanism 6. Thereby, the product P can be taken out even if the lower mold 1 does not have a take-out device such as an eject pin for taking out a molded product.

  The obtained product P is appropriately unloaded and collected by an unloader or the like and sent to the next process. Further, burrs, dirt, etc. on the divided surface of the mold are cleaned by a cleaner or the like, and the next molding cycle process is prepared.

  According to the sealing molding apparatus of the present invention described above, a so-called gate break process for separating unnecessary resin such as runner resin remaining in the runner portion and the molded product as in a conventional resin-sealed semiconductor package. Thus, a resin-sealed semiconductor package having a gate break can be obtained without going through the process, thereby increasing the yield of the resin and not discharging unnecessary resin. In addition, it is possible to obtain a good product with less wire flow in the obtained product.

  The effects of the present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

  A resin-encapsulated semiconductor package was manufactured using an encapsulating apparatus according to the drawings shown in FIGS. As the sealing resin, Sumitomo Bakelite Co., Ltd. epoxy resin molding material Sumicon “EME-7730” (trade name) was used.

  The molding conditions are as follows: the temperature of the stirring pot (stirring cup 32) is 100 ° C., the stirring time is 30 seconds, the injection pressure is 9 MPa, the injection time is 12 seconds, the mold temperature (the temperatures of the lower mold 1 and the upper mold 2). ) Was adopted at 175 ° C.

  As a mold, a chip size package of 24 chips / 1 frame is used for batch molding, and a lead frame bonded with a gold wire with a bonding wire (25 μm diameter, length 2.8 mm semi-hard wire) is set in the mold. The molded product that was molded and sealed was measured for unfilled, external voids, internal voids, and wire flow. In addition, the numerical value of the wire flow in Table 1 is shown by the average of the maximum deformation amount of 18 chips.

  For comparison, multi-transfer molding using a general mini tablet, preheating in the mold for 4 seconds, and other molding conditions being the same, and TAB compression molding in which the mini tablet is preheated in the mold for 4 seconds and compression molded And compared.

  The results are also shown in Table 1.

<Measurement method>
Twenty of the molded products were randomly extracted and measured according to the following evaluation method.
1. Unfilled (short shot): The presence or absence of unfilled portions on the surface was visually observed. 2. External voids: The presence or absence of voids having a size exceeding φ0.5 mm on the surface was visually observed.
3. Internal voids: The molded product was irradiated with soft X-rays, and the presence or absence of voids having a size exceeding φ0.3 mm was observed.

In the numerical values shown in Table 1, the denominator is the number of observed packages (number), and the numerator is the number of packages (number) in which an abnormality has occurred.
4). Wire flow (gold wire deformation): The molded product was irradiated with soft X-rays, and the deformation amount of the bonding wire was measured. The ratio of the maximum wire deformation amount to the distance between the semiconductor (IC) element end face and the lead terminal bonding is shown in%.

  The second embodiment is an embodiment for confirming the influence on the performance of the molded product when the shape of the tip surface 3a of the molded plunger 3 is changed variously.

  A 12-chip / 1-frame batch molding (MAP) chip size package CPS is used. The chip size of each semiconductor device H is 3.50 mm, and the bonding wire W is a high-strength gold wire having a diameter of 25 μm and a length of 3.30 mm.

  Also, the molding pot temperature is 100 ° C., the stirring time is 30 seconds, the injection pressure is 9 MPa, the injection time is 8 seconds, and the mold temperature (the temperature of the lower mold 1 and the upper mold 2) is 175 ° C. did.

  Except that the product (resin-encapsulated semiconductor package) P having the concavo-convex mark 3ab ′ as shown in FIGS. 12 to 14 can be obtained by changing the shape of the front end surface 3a, according to Example 1. Molded.

  As a result, the lead frame bonded with the gold wire was set in the mold and molded, and the sealed product P was measured in the same manner as in Example 1 for unfilled, external void, internal void, and wire flow. The results are shown in Table 2. In addition, the numerical value of the wire flow in Table 2 shows the maximum deformation amount of the package number n = 3 as an average value.

  Here, in Example 2 of FIG. 12, the distance between the product outline 4ab ′ and the uneven mark 3ab ′ (corresponding to the width w of the bottom surface 4a) is designed to be approximately 0.3 mm, and the radius of curvature of the square 3R of the plunger 3 is designed. Is designed to be approximately 2 mm, the area ratio of the tip surface 3a (the region surrounded by the concave / convex mark 3ab 'in the drawing) to the area of the region surrounded by the external line 4ab (the product external line 4ab' in the drawing) 'is reduced. It is designed to be approximately 96.5%.

  Further, in Comparative Example 2 in FIG. 13, the width w of the bottom surface 4a is designed to be about 0.6 mm, and the radius of curvature of the square 3R of the plunger 3 is designed to be about 10 mm, so that the area surrounded by the outline 4ab is reduced. The area ratio of the front end surface 3a is about 85.2%.

  14 is an example of a mold according to a comparative example of the present invention, and the shape of the distal end surface 3a of the molding plunger is designed to be circular, and the minimum between the outline 4ab and the outline 3ab. Since the width w is designed to be approximately 0.3 mm, the area ratio of the tip surface 3a to the area surrounded by the outline 4ab is 76.5%.

  Accordingly, in Example 2, the dicing line DL is within the frame of the concave and convex mark 3ab ′ including the four corners DLa, but in Comparative Example 2, the four corners DLa of the dicing line DL are more than the four corners 3R ′ of the outline 3ab ′. Further, in Comparative Example 3, the concave / convex mark 3ab ′ greatly hangs on the semiconductor package H at the four corners.

  From the above results, the shape of the tip surface 3a is similar, and the area of the tip surface of the molding plunger is 90% or more with respect to the area of the bottom molding surface of the lower mold cavity. It is understood that unfilled, external voids, internal voids, and wire flow are reduced.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention. .

  The present invention is most suitable for packages in which wire flow is likely to occur and high reliability is difficult to obtain when semiconductor packages are made larger, thinner, and highly integrated. The present invention can be applied to a manufacturing method and a manufacturing apparatus of a resin-encapsulated semiconductor package that can be used.

  Furthermore, according to the manufacturing method of the present invention, even when the manufacturing process is inlined and the manufacturing process of the resin-encapsulated semiconductor package is fully automated, the sealing process can be performed inline.

It is a top view which shows the principal part of the lower mold | type of the sealing molding apparatus which concerns on the Example of this invention. It is sectional drawing at the time of cut | disconnecting by the XX line of the lower mold | type of FIG. It is explanatory drawing which shows the whole sealing molding apparatus which concerns on the Example of this invention from the side. It is A arrow directional view of FIG. FIG. 4 is a view taken in the direction of arrow B in FIG. 3. It is C arrow line view of FIG. It is a top view explaining the condition of the lower mold | type after molten resin MR supply which is one process of sealing with the sealing molding apparatus which concerns on the Example of this invention. It is explanatory drawing explaining the condition after the mold clamping which is one process of the sealing by the sealing molding apparatus which concerns on the Example of this invention with a cross section. It is explanatory drawing explaining the compression molding process which is one process of sealing with the sealing molding apparatus which concerns on the Example of this invention by a cross section. It is explanatory drawing explaining the state which opened the lower mold | type 1 for demonstrating the shape of the molded product shape | molded by FIG. 9 by a plane. It is explanatory drawing explaining the demolding process which is one process of sealing with the sealing molding apparatus which concerns on the Example of this invention. It is explanatory drawing explaining the product P which concerns on Example 2 of this invention. It is explanatory drawing explaining the product P which concerns on the comparative example 2 of this invention. It is explanatory drawing explaining the product P which concerns on the comparative example 3 of this invention. It is explanatory drawing explaining the process of sealing with the conventional sealing molding apparatus by a cross section. Explanatory drawing explaining the process of sealing by the conventional sealing molding apparatus by a cross section

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lower mold block 2 ... Upper mold block 3 ... Molding plunger 3a ... End surface 3ab ... Outline line 3ab '... Concave / concave mark 4 ... Cavity molding part (mold part)
4a ... bottom surface 4b ... side surface 4ab ... outline 4ab '... product outline 5 ... through portion 6 ... advance / retreat mechanism 7 ... resin receiving portion 20 ... resin material supply device 21 ... measuring unit 25 ... weighing pot 31 ... stirring unit 32 ... Stir cup 37 ... plunger 37a ... stir bar 41 ... feed unit 45 ... vertical movement motor 51 ... moving unit 52 ... moving motor 61 ... molding mold (lower mold)
DL ... Dicing line DLa ... Corner H ... Semiconductor device P ... Product (resin-encapsulated semiconductor package)
W ... Wire (bonding wire)
w ... Width

Claims (4)

A molding apparatus having a mold clamping mechanism and a molding plunger advancing and retreating mechanism, and in the lower mold cavity portion, a resin receiving portion for receiving a sealing resin is formed on the top end surface in a state in which the molding plunger is retracted, and A molding plunger for compression molding that forms and forms the bottom molding surface of the lower mold cavity while compressing the sealing resin whose front end surface is supplied to the resin receiving portion while the molding plunger is advanced is loaded so as to be able to advance and retreat. A mold composed of a lower mold, an upper mold that can be clamped by a mold clamping mechanism, and a sealing melt that is stirred and melted in the resin receiving portion in a state where the mold is opened. In a sealing molding apparatus provided with a resin supply device for supplying resin,
The outer shape of the tip surface of the molding plunger is designed to be substantially similar to a small shape within a range of 0.1 to 0.5 mm from the shape of the bottom molding surface of the lower mold cavity. Seal molding device. A molding apparatus having a mold clamping mechanism and a molding plunger advancing and retreating mechanism, and in the lower mold cavity portion, a resin receiving portion for receiving a sealing resin is formed on the top end surface in a state in which the molding plunger is retracted, and A molding plunger for compression molding that forms and forms the bottom molding surface of the lower mold cavity while compressing the sealing resin whose tip surface is supplied to the resin receiving portion in a state where the molding plunger has advanced is loaded so as to be able to advance and retreat. A mold composed of a lower mold, an upper mold that can be clamped by a mold clamping mechanism, and a sealing melt that is stirred and melted in the resin receiving portion in a state where the mold is opened. In a sealing molding apparatus provided with a resin supply device for supplying resin,
The sealing molding apparatus characterized in that an area of a tip surface of the molding plunger is 90% or more with respect to an area of a bottom molding surface of the lower mold cavity. Using the device according to claim 1 or 2,
(A) a resin supply step of supplying a sealing resin to the resin receiving portion in a state where the mold is opened;
(B) a mold clamping process in which the upper mold and the lower mold are clamped by the mold clamping mechanism;
(C) a compression molding process in which the tip surface of the molding plunger is raised to the molding surface and the semiconductor device is sealed and cured by the molten resin received in the resin receiving portion;
(D) A method for manufacturing a resin-encapsulated semiconductor package, comprising sequentially performing a demolding step of opening the mold and taking out the obtained resin-encapsulated semiconductor package.   Dicing within a frame of concavo-convex lines along the outer shape of the distal end surface of the molding plunger formed on the bottom surface of the resin-encapsulated semiconductor package obtained by the method for producing a resin-encapsulated semiconductor package according to claim 3 A method for manufacturing a resin-encapsulated semiconductor package.

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