JP2004296962A - Sealing molding apparatus and method for manufacturing resin sealer using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing molding apparatus and a method for manufacturing a sealing molded body using the same, in which the sealing molded body which is hard to cause a wire flow even in forming a fine-line wire can be obtained. <P>SOLUTION: The molding apparatus is one having a lock mechanism and an advance or retreat mechanism of a molding plunger. The molding apparatus comprises a lower die 1 in which a lower die cavity part 4 is formed with a resin socket part 7 for receiving a sealing resin in an upper part of a tip plane 3a in a state that a molding plunger 3 is retreated, and also the molding plunger 3 for compression molding in which, in a state that the molding plunger 3 is advanced, the tip plane compresses a sealing resin fed to the resin socket part, while forming a bottom molding plane of a lower die cavity to mold is filled so as to advance or retreat; a die which is constituted of the lower die 1 and an upper tool 2 which can be locked by a lock mechanism 6; and a resin feeding device 20 which feeds a sealing resin MR which is stirred and melted in the resin socket part 7 in a state that the die is opened. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６８】
＜測定方法＞
成形品の２０個を無作為に抽出し、以下の評価方法に従って測定した。
１．未充填（ショートショット）：目視で表面の未充填個所の有無を観察した。
２．外部ボイド：目視で表面のφ０．５ｍｍを超える大きさのボイドの有無を観察した。
３．内部ボイド：成形品に軟Ｘ線を照射してφ０．３ｍｍを超える大きさのボイドの有無を観察した。
【００６９】
なお、表１に示す数値は、分母は観察したパッケージ数（個数）であり、分子は異常が発生されたパッケージ数（個数）である。
４．ワイヤー流れ（金線変形）：成形品に軟Ｘ線を照射して、ボンデイングワイヤ（２５μｍ径、長さ２．８ｍｍのセミハード金線）の変形量を測定した。半導体（ＩＣ）素子端面とリード端子のボンデイング間の距離に対する最大ワイヤ変形量の比を％で示した。なお、表１における数値は１８チップの最大変形量の平均で示している。
【００７０】
以上、この発明の実施の形態を図面により詳述してきたが、具体的な構成はこの実施の形態に限らず、この発明の要旨を逸脱しない範囲の設計の変更等があってもこの発明に含まれる。
【００７１】
さらに、本発明の製造方法によれば、製造工程のインライン化されて半導体装置の製造工程が全自動化された場合にも、封止工程をインラインで行うことが可能である。
【００７２】
【発明の効果】
以上説明してきたように、この発明によれば、封止部材中での溶融樹脂の流れ方向は、封止部材に略直交する方向であり、樹脂が均一に溶融されていること及び流れるべき樹脂量が少ないことなどに起因して、封止部材の周辺の溶融樹脂の流速が遅くてよく、封止部材にワイヤーの極細線が装填されていてもワイヤー流れが生じない、更に、金型内に樹脂を受け入れた後のプレヒート工程時間の短縮、成形サイクルの短縮、樹脂廃棄量の大幅削減などが可能な封止成形装置及びそれを用いた樹脂封止体の製造方法が提供できる、という実用上有益な効果を発揮する。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る封止成形装置の下型の要部を示す平面図である。
【図２】図１の下型のＸ−Ｘ線で切断した場合の断面図である。
【図３】本発明の実施の形態に係る封止成形装置の側面を示す説明図である。
【図４】図３のＡ矢視図である。
【図５】図３のＢ矢視図である。
【図６】図３のＣ矢視図である。
【図７】本発明の実施の形態に係る封止成形装置による封止の一工程である溶融樹脂ＭＲ供給後の下型の状況を説明する平面図である。
【図８】本発明の実施の形態に係る封止成形装置による封止の一工程である型締め後の状況を断面により説明する説明図である。
【図９】本発明の実施の形態に係る封止成形装置による封止の一工程である圧縮成形工程を断面により説明する説明図である。
【図１０】図９により成形された成形品の形状を説明するための下型１を型開きした状態を平面により説明する説明図である。
【図１１】本発明の実施の形態に係る封止成形装置による封止の一工程である脱型工程を説明するの説明図である。
【図１２】従来の封止成形装置による封止の工程を断面により説明する説明図である。
【図１３】従来の封止成形装置による封止の工程を断面により説明する説明図
【符号の説明】
１…下型ブロック
２…上型ブロック
３…成形プランジャ
３ａ…先端面
４…キャビティ成形部（モールド部）
４ａ…底面
４ｂ…側面
５…貫通部
６…進退機構
７…樹脂受入部
２０…樹脂材料の供給装置
２１…計量ユニット
２５…計量ポット
３１…撹拌ユニット
３２…撹拌カップ
３７…プランジャ
３７ａ…撹拌棒
４１…供給ユニット
４５…上下動用モータ
５１…移動ユニット
５２…移動用モータ
６１…成形金型（下型）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sealing molding apparatus for manufacturing a resin sealing body in which a semiconductor device such as a transistor or an IC is sealed with a resin, and a method for manufacturing a resin sealing body using the same.
[0002]
[Prior art]
2. Description of the Related Art Transfer molding using a transfer molding apparatus is widely used as a method for efficiently molding a resin encapsulated body (a so-called package or resin-encapsulated semiconductor device) by encapsulating a semiconductor device (semiconductor chip) such as a transistor or an IC with a resin. It is used (for example, Patent Document 1).
[0003]
In this method, 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 is heated and melted, and injected into a mold using a transfer molding machine. This is a method in which a semiconductor chip mounted on, for example, a lead frame is sealed by molding and curing in a state of high temperature and high pressure.
[0004]
The resin-encapsulated semiconductor device (resin-encapsulated body) manufactured by this method has excellent reliability because the epoxy resin composition completely covers the semiconductor chip, and the package is densely molded with a mold. At present, most resin-encapsulated semiconductor devices are manufactured by this method because the appearance of the die is good.
[0005]
In this transfer molding apparatus, a tablet of a thermosetting resin to be sealed in a pot is supplied, and the resin received in the pot is fed to the mold cavity while being melted. In a state where the sealing resin is sufficiently filled in the mold cavity, curing (curing) proceeds to form a resin sealing body.
[0006]
On the other hand, a sealing resin sheet made of an uncured resin is arranged 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 attached to the semiconductor chip. A method of manufacturing a resin-encapsulated semiconductor device including a sealing step of sealing a semiconductor chip by curing while pressurizing the semiconductor chip (hereinafter, may be abbreviated as a compression molding method) has been proposed. (For example, Patent Document 2).
[0007]
Further, when the sheet-shaped resin R is directly molded in the cavity, as shown in FIG. 12, 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'. (For example, Patent Document 3). The plunger 3 may be provided only on the lower mold 1 as shown in FIG.
[0008]
A molding plunger 3 is slidably provided in the cavity molding portion 4 of the lower mold 1 such that the lower bottom surface of the cavity becomes the front end surface 3a. In addition, a molding plunger 3 'is slidably provided in the cavity molding portion 4 of the upper die 2 such that the upper bottom surface of the cavity becomes the tip end surface 3'a.
[0009]
In such an apparatus, the sheet-shaped resin SR is placed and charged on the upper surface of the lead frame F and the cavity forming section 4 of the lower mold 1, respectively. The sheet-shaped resin SR starts melting 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 keeps descending together with the lead frame F, clamps the lead frame F with the lower mold 1, clamps the mold, and at the same time, completes the upper mold. The molding plunger 3 'in 3 descends (retreats) to a predetermined position and stops. Next, the molding plunger 3 in the lower mold 1 is raised (advanced), and the resin is compression-molded to obtain a sealing molded body P in which the semiconductor device H of the lead frame F is sealed with the resin.
[0010]
According to such a compression molding method, the sealing process can be automated and inlined, and it is suitable for making the package larger and thinner, and it is required to have high package accuracy and high package reliability. It has been proposed that it can be used as a method of manufacturing a corresponding resin-encapsulated semiconductor device.
[0011]
[Patent Document 1]
JP-A-8-111465 (prior art section and FIG. 19)
[Patent Document 2]
JP-A-6-275767 (FIGS. 10 and 11)
[Patent Document 3]
JP-A-8-330342 (FIGS. 13 and 14)
[0012]
[Problems to be solved by the invention]
However, according to the transfer molding apparatus described in Patent Literature 1, a considerable portion of a resin tablet made of an expensive resin material is discarded as unnecessary cured resin. Moreover, since the resin tablet is manufactured on the premise that it is originally used as a sealing resin, the cured resin to be discarded also has a high quality enough to satisfy the demand for the sealing resin. Therefore, high-quality resin is discarded, and there is a problem not only in terms of cost but also in terms of effective use of resources.
[0013]
Further, the cull portion and the runner portion are respectively designed according to the size (outer diameter) of the resin tablet. Therefore, there is a certain limit even if an attempt is made to reduce the discarded portion of the resin tablet and improve the ratio of the portion used as the sealing resin to the whole, that is, to improve the resin yield.
[0014]
Further, according to such a transfer molding apparatus, a resin tablet having a different size must be used for each different size of the mold cavity. As a result, it is necessary to stock a plurality of types of resin tablets, and inventory management of the resin tablets becomes complicated.
[0015]
Further, it is necessary to prepare a transport 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.
[0016]
On the other hand, according to the compression molding methods described in Patent Literatures 2 and 3, culls, runners, and gates are not required, so that the amount of unnecessary resin waste due to cull resin and the like is eliminated. Further, since the cull portion, the runner portion, and the gate portion are not required, there is a feature that the mold and the entire device can be made compact.
[0017]
However, in recent years, the package of resin-encapsulated semiconductor devices has been increasing due to the increase in the size of semiconductor chips accompanying the high integration of semiconductor devices. And the density has been increased, and this tendency is expected to become stronger in the future.
[0018]
Here, according to the conventional compression molding method, there is a problem that a wire flow occurs. As a result, there has not been proposed a highly reliable sealing molding apparatus or a method of manufacturing a sealing molded body that can cope with a case where a wire is further thinned. In particular, when the thickness of the encapsulant is reduced 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 is likely to be in contact with an adjacent bonding wire. This problem is also a problem in the case where a so-called inner lead bonding method is used in which electrical connection with a chip is made directly to the tip of a lead such as a film carrier via a bump or the like.
[0019]
Therefore, an object of the present invention is to provide a sealing molding apparatus capable of obtaining a sealing molded article in which wire flow is unlikely to occur even when a wire is thinned, and a method of manufacturing a sealing molded article using the same. I do.
[0020]
Further, the present invention eliminates the need for a resin tablet, reduces the size and simplification of the encapsulation molding device, and reduces the amount of high-quality resin to be discarded, thereby reducing manufacturing costs and effectively using the resin. It is an object of the present invention to provide a sealing molding apparatus capable of performing the above and a method for producing a sealing molding using the same.
[0021]
[Means for Solving the Problems]
According to a study by the present inventors, in a conventional method using compression molding, a resin receiving portion for receiving a sealing resin is provided below a lower mold cavity portion, and after the resin that has been stirred and melted is received in the resin receiving portion. The present inventors have found that if the received resin is supplied from the lower surface of the semiconductor device and sealing is performed, even if the wire is thinned, the flow of the wire is small and the sealing can be performed.
[0022]
That is, the present invention relates to a molding apparatus having a mold clamping mechanism and an advancing / retracting mechanism of a molding plunger, wherein the lower mold cavity portion has a resin receiving portion for receiving a sealing resin at an upper portion of a front end surface of the molding plunger in a retracted state. The molding plunger for compression molding moves forward and backward by forming the bottom molding surface of the lower mold cavity while forming the bottom molding surface of the lower mold cavity while the sealing resin supplied to the resin receiving portion is compressed while the molding plunger is advanced. A lower mold that can be loaded, a mold composed of the lower mold and an upper mold that can be mold-clamped by a mold-clamping mechanism, and the mold is opened and stirred and melted in the resin receiving section. And a resin supply device for supplying a sealing resin.
[0023]
According to such a sealing molding apparatus, (a) a resin supply step of supplying a sealing resin to the resin receiving portion in a state of being stirred and melted with the mold opened, (b) a mold clamping mechanism (C) Compression in which the tip end 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. By sequentially performing a molding step and (d) a mold release step of opening the mold and taking out the obtained resin sealing body, a sealing molded body with a small wire flow can be manufactured.
[0024]
Further, according to such a manufacturing method, since a cull, a runner and a gate are not required, not only the amount of resin used can be reduced, but also a mold and a device can be made more compact. Cost reduction is also possible.
[0025]
Further, according to the present invention, since the resin supplied to the mold is stirred and melted, the preheating time in the mold can be reduced, and the production cycle can be improved.
[0026]
In addition, the sealing resin supplied to the resin supply device may be in the form of powder, granules, and does not need to be in the form of a sheet or a resin tablet, so that a molding step of the sealing resin is unnecessary, and There is no need for inventory control when using resin tablets.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. Parts that are the same as or equivalent to those of the sealing molding apparatus described in the related art will be described with the same reference numerals.
[0028]
FIG. 1 is a plan view illustrating a lower mold cavity block as a lower mold used in a sealing molding apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line XX in FIG. It is sectional drawing.
[0029]
In this drawing, reference numeral 1 denotes a lower mold or a lower mold cavity block which is exchangeably mounted on the lower mold, and a cavity molding section (mold section) 4 as a product molding section is provided at the center. A substantially central portion of the bottom surface 4a of the mold portion 4 is penetrated in a cylindrical shape, and the penetrating portion 5 is loaded with a vertically movable plunger 3. When the tip surface 3a of the molding plunger 3 is at the same height as the bottom surface 4a, the lower mold cavity becomes equal to the mold portion 4.
[0030]
The molding plunger 3 can be advanced and retracted by an advance and retreat mechanism 6 for compression molding. Although the advance / retreat mechanism 6 is not particularly limited, a mechanism that can accurately control the advance / retreat amount by, for example, a servomotor or an encoder is used. The ball screw is rotated by a timing belt or the like under the control of the rotation of a servo motor (not shown) to convert the rotation of the servo motor into a vertical movement. The position of the tip surface 3a of the molding plunger 3 can move the molding plunger 3 back and forth to a desired position while controlling the rotational speed of the servomotor with an encoder.
[0031]
Here, for compression molding means an advancing / retracting mechanism capable of holding the pressure required for compression molding, and when it is necessary to control the pressure, it can be placed at an arbitrary position via a pressure sensor such as a pressure sensor. It is assumed that a mechanism capable of controlling the molding pressure is provided. Such a pressure control mechanism is known. 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 required pressure by the pressure detected by the pressure detector. Can be.
[0032]
The position of the tip end surface 3a of the molding plunger 3 is retracted from the position of the lower surface 4a of the mold portion 4 (hereinafter, referred to as a mold matching position) to form the resin receiving portion 7 for receiving the resin on the tip end surface 3a. In FIG. 2, the molding plunger 3 is retracted to form a resin receiving portion 7 on the distal end surface 3a.
[0033]
Here, in the present invention, a predetermined amount of the sealing resin melted by stirring is supplied to the resin receiving portion 7.
[0034]
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, and has a good thermal stability in the heated injection unit or the cylinder. It is preferable that the material has particularly good fluidity in the mold portion 4 and is quickly cured. Such sealing resins are known, for example, epoxy resins, phenolic resin curing agents, and the like described in JP-A-8-67741, JP-A-8-67742, and JP-A-8-67745. An epoxy resin encapsulating material containing a curing accelerator and an inorganic filler as essential components is exemplified as an example. As such a sealing resin, a powdery or granular resin can be used as it is.
[0035]
For supplying the sealing resin, an injection device (or an injection unit) of an injection molding apparatus developed for sealing such a sealing resin (thermosetting resin) by injection molding can be used. Such an injection apparatus 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 by a mold clamping unit. This is an injection unit provided to be able to move forward and backward with respect to the mold. In addition, a screw-in-line type injection unit described in JP-A-2001-189333, and a powdery or granular epoxy resin sealing material disclosed in JP-A-2000-68416 are supplied and uniformly kneaded by a screw mechanism. It may be an injection unit that melts and injects it into the cavity with a screw or plunger. The screw in-line type is preferable from the viewpoint of easy temperature control, uniform melting, and the like.
[0036]
In the present invention, the resin supply device is basically an injection device (or an injection unit) provided with a stirring device such as a screw type or an in-line screw type, and an injection device (or an extrusion device) such as a heating device and a plunger type. I just need. 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, the injection speed is not particularly limited. It is sufficient that the resin stirred by the injection can be supplied to the mold.
[0037]
In the present invention, the sealing resin is preferably uniformly stirred and melted. For this reason, in the present invention, a resin supply device provided with a heating device, a stirring device, and an injection device is preferably used. The stirred and melted resin becomes a low-viscosity fluid state in which a solid resin material such as a powder or a granule is melted by heating and stirring.
[0038]
If the viscosity of the supplied resin is high, if the molding cycle is advanced, deformation and cutting of the bonding wire on the semiconductor element may occur, and in a diode or the like, the electrical performance of the internal element may be reduced. . On the other hand, there is no lower limit on the viscosity of the supplied resin, but this shows that the lower limit of the viscosity when heated to 80 ° C. to 120 ° C. with the resin that provides the necessary sealing performance is about this.
[0039]
In the present invention, by supplying the heated resin to the mold, the molding cycle can be shortened and the productivity can be improved. Further, in the present invention, it is possible to supply a resin in a low-viscosity flow state in which a wire flow or the like hardly occurs to a mold. A preferred example of such a resin supply device is described in detail in JP-A-2001-341155.
[0040]
This resin supply device is, for example, a measuring unit that can load a predetermined amount of resin material into each measuring pot arranged below via a measuring means in which a screw is inserted into a measuring pipe at the lower part of a hopper storing a resin material. And a stirrer rod from the tip via a stirrer having a plunger inserted into a stirrer cup in which a resin material is transferred between a plurality of stirrer cups and a plurality of stirrer cups arranged in parallel with the pot. A stirring unit that enables stirring by rotation of each protruding plunger, and a stirring unit that moves from the measuring unit to the molding die via a moving unit provided with pulleys and belts that are mounted on a motor that can move forward and backward. The resin material in the agitating cup is fed through a moving unit capable of moving forward and backward, and up and down moving means provided with pulleys and belts attached to a motor capable of moving forward and backward. Towards, and a possible and the supply unit extrusion feed in the plunger.
[0041]
Here, in the present invention, instead of a molding die having a mold pot, a compression molding apparatus is used in which the molding surface is the distal end surface 3a of the plunger and the resin receiving portion 7 is provided on the distal end surface 3a. After the heated and stirred resin is received in the resin receiving portion 7, the resin is clamped, and the molding plunger 3 is heated and cured by raising the molding plunger 3 to a predetermined position to complete the molding. There is provided a molding method in which a wire flow is hardly generated as compared with a compression molding method in which a conventional sheet-shaped resin is charged.
[0042]
Here, if the compression molding device or the resin receiving section 7 can be provided to the supply unit by a moving unit or the like, the moving unit described in JP-A-2001-341155 becomes unnecessary. Such a compression molding apparatus or lower mold can be incorporated into a line of a semiconductor manufacturing apparatus by using a turntable, a movable unit that can move forward and backward, and a movable unit that flows in one direction. Of course, in the present invention, a structure in which the resin supply device and the resin receiving portion 7 are fixed to each other may be employed.
[0043]
Hereinafter, a description will be given of a sealing molding apparatus and a method of manufacturing a sealing molded body for supplying and molding the stirred resin to the lower mold cavity block 1 by the resin material supplying apparatus.
[0044]
As shown in FIGS. 3 to 6, the sealing molding device 20 including the resin material R supply device guides the resin material R stored in the hopper 22 into the measuring pipe 24 a by rotating the screw 24. The measuring unit 21 to be measured in the pipe 24a by the screw rotation speed and loaded into the measuring pot 25, and the measured resin material R are transferred between the measuring pot 25 and the stirring cup 32, and the stirring cup 32 Then, a plunger 33 having a stirrer bar 33a protruding from its tip is inserted and rotated to stir and melt, and the stirrer unit 31 is moved toward a molding die (lower die) 61 while operating the stirrer unit 31. When the moving unit 51 to be moved and the stirring unit 31 are moved and the stirring cup 32 is positioned on the resin receiving portion 7 of the lower mold block 1 set to be exchangeable with the lower mold 61, By actuating the plunger 33 mounted on 拌 unit 31, the resin material molten in stirred cup 32, and a supply unit 41 for supplying the resin receiving part 7.
(A) Resin supply step
The stirring unit 31, the moving unit 51, and the supply unit 41 perform a series of operations, respectively, to supply the lower mold 61 with a predetermined amount of the powdery or granular resin material R supplied to the measuring unit 21A of the measuring unit 21. Is supplied in a state of being stirred and melted.
[0045]
In the series of these operations, in the weighing unit 21, the resin material R supplied to the hopper 22 is rotated in the hopper 22 around the screw 24 rotated by the operation of the weighing motor 23, and the breaking pin 22c also rotates. The resin material R is broken without bridging, and is supplied to the screw 24 so as to be easily bitten. The screw 24 measures a predetermined amount at a predetermined rotation speed in the measuring tube 24a, and is loaded from the measuring section 21A into the measuring pot 25 of the pot section 25A.
[0046]
By the operation of the feed motor 27, the measuring unit 21A loads all the measuring pots 25 with the resin material R while moving on the respective measuring pot upper end surfaces 25a.
[0047]
When each of the measuring pots 25 is loaded, the pot moving cylinder 28 is operated to move the pot portion 25A rightward, and the cup moving motor 33 is also operated leftward so that the stirring cup 32 is greeted. Then, the shutter plate 26a is opened by operating the opening / closing cylinder 26 below the measuring pot 25, and the measured resin material R is transferred. Then, it is moved back to the right and positioned below the plunger 37.
[0048]
Next, the four stirrer rod cylinders 36a are operated to cause the stirrer rods 37a to protrude from the tip of the plunger 37, and then the stirrer motors 38 with the gears 38a mounted on the shafts are operated. The plunger 37 is rotated through each of the gears 38b to stir and melt the resin material R in the stirring cup 32. Here, the temperature of the stirring cup 32 is appropriately set depending on the resin material R to be used, but is most generally heated within the range of 80 ° C. to 120 ° C.
[0049]
In the stirring unit 31, the moving motor 52 of the moving unit 51 is quickly operated while stirring to move the timing belt 54 forward to a position where the limit switch 56a is braked.
[0050]
When the stirring and melting are completed, the stirring cylinder 36a is operated, the movable plate 44 is raised, and the stirring rod 37a is drawn into the cylinder 37 to be buried.
[0051]
Then, at the stop position of the stirring unit 31, the supply unit 41 incorporated in the stirring unit 31 is operated.
[0052]
In other words, the motor 45 for vertical movement is operated to rotate the ball screw 42 via the pulley 45a and the belt 45b which are attached to the shaft, and the ball screw nut 43 which moves downward and is attached to the ball screw nut 43 by the lower connecting plate 36. The plunger 37 is lowered at once, and the molten resin MR melted in the stirring cup 32 is supplied to the resin receiving section 7 provided in the lower mold 61.
[0053]
The temperature of the molten resin MR supplied to the resin receiving portion 7 varies depending on the type of the resin material R used, but the most common case where the mold temperature is 170 ° C. to 180 ° C. (for example, about 175 ° C.) 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 agitated and homogenized and has a low viscosity, the molten resin MR supplied to the resin receiving portion 7 is rapidly developed in the plane direction while being further heated at the temperature of the mold ( (FIG. 7).
[0054]
On the other hand, in this embodiment, the stirring unit 31 that has completed the supply moves the timing belt 54 backward by the reverse rotation of the moving motor 52 and stops by the braking of the limit switch 56a. Is moved rearward to the position of the pot portion 25A to prepare for the next resin supply step.
(B) Clamping process
Next, the preheated lead frame F is positioned on the mold part 4 and loaded on the lower mold surface 1a via an unloader (not shown) for accumulating, aligning and carrying out the lead frame (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 CSP is loaded with the surface to be sealed facing the lower surface. The mold is closed by a mold clamping mechanism that lifts and lowers at least one of the upper mold 2 and the lower mold 1 (FIG. 8).
(C) Compression molding process
Next, as shown in FIG. 9, the compression molding is performed while driving the advance / retreat mechanism 6 to raise (advance) the tip end surface 3 a of the molding plunger 3 to the mold matching position (molding surface). Thereby, the molten resin MR supplied to the resin receiving section 7 flows toward the mold section 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.
[0055]
Further, 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 moving in the sealing member including the wire W is set. May be short, and the flow rate of the molten resin MR across the wire W is low, so that even when the wire W is thinned, the wire flow is less likely to occur. Thus, 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.
[0056]
Here, these mold temperature, pressure and holding time vary depending on the performance of the resin to be used, the size of the mold, the size of the package, and the like. The curing holding time and the like are not limited to the above example.
[0057]
According to such an apparatus, in a compression-molded semiconductor device (product P), the surface 3a 'formed by the molding plunger 3 in the lower mold 1 moves up and down due to variation in the amount of resin. A concave (or convex) mark is formed along the shape of the surface 3a. Here, in this embodiment, as shown in FIG. 10, since the outer shape of the distal end surface 3 a of the plunger 3 is designed to be slightly smaller than the outer shape of the bottom surface 4 a of the cavity part 4, It is formed in a fringe shape on the periphery of the semiconductor device, and is formed at a position that does not substantially affect the performance of the product. If the shape of the distal end surface 3a of the plunger 3 is made substantially equal to the shape of the bottom surface 4a of the cavity portion 4, this uneven mark is not substantially formed.
(D) Demolding process
After the curing is completed, the upper and lower molds (die) are opened by the mold clamping mechanism, and the product P as a molded product is taken out by an arbitrary method. In order to take out the product P, for example, a suction device such as a suction cup is used, but the product P may be taken out using a knockout pin or an ejector plate. In addition, if the plunger 3 is configured to be able to protrude from the mold part 4, the plunger 3 can be easily taken out even if the side surface 4b of the mold part 4 does not have a gradient.
[0058]
Further, as shown in FIG. 11, the product P can be taken out by lowering (retreating) the plunger 3 by the advance / retreat mechanism 6. Thus, the product P can be taken out even if there is no ejection device such as an eject pin for taking out the molded product in the lower mold 1.
[0059]
The obtained product P is appropriately carried out and accumulated by an unloader or the like, and sent to the next process. Further, burrs and dirt on the divided surface of the mold are cleaned by a cleaner or the like, and the process proceeds to preparation for the next molding cycle process.
[0060]
According to the above-described sealing molding apparatus of the present invention, a so-called gate break process is performed, which separates a molded product from unnecessary resin such as a runner resin remaining in a runner portion or the like, like a conventional resin molded body. Thus, it is possible to obtain a gate-breaked resin sealing body without increasing the resin yield and discharging unnecessary resin. In addition, a good product with a small wire flow can be obtained from the obtained product.
[0061]
Hereinafter, the effects of the present invention will be described with reference to examples, but the present invention is not limited to the following examples.
[0062]
【Example】
A sealing molding was manufactured using a sealing molding device according to the drawings shown in FIGS. 1 to 11. As an encapsulation resin, an epoxy resin molding material Sumicon “EME-7730” (trade name) manufactured by Sumitomo Bakelite Co., Ltd. was used.
[0063]
The molding conditions were as follows: the temperature of the stirring pot (stirring cup 32) was 100 ° C., the stirring time was 30 seconds, the injection pressure was 9 MPa, the injection time was 12 seconds, and the mold temperature (the temperature of the lower mold 1 and the upper mold 2 was lower). ) At 175 ° C.
[0064]
As a mold, using a 24 chip / 1 frame chip size package for batch molding, the lead frame to which the wire bonding is performed is set in the mold and molded. Voids, internal voids, and wire flow were measured.
[0065]
As a comparison, multi-transfer molding using a common mini-tablet and pre-heating in the mold for 4 seconds and other molding conditions were the same, and TAB compression molding in which the mini-tablet was pre-heating in the mold for 4 seconds and compression molding was performed Was compared.
[0066]
The results are shown in Table 1.
[0067]
[Table 1]

[0068]
<Measurement method>
Twenty molded articles were randomly extracted and measured according to the following evaluation methods.
1. Unfilled (short shot): The presence or absence of unfilled portions on the surface was visually observed.
2. External void: The presence or absence of a void 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 to observe the presence or absence of voids having a size exceeding φ0.3 mm.
[0069]
In the numerical values shown in Table 1, the denominator is the number of packages (number) observed, and the numerator is the number of packages (number) where 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 (semi-hard gold wire having a diameter of 25 μm and a length of 2.8 mm) was measured. The ratio of the maximum amount of wire deformation to the distance between the end surface of the semiconductor (IC) element and the bonding of the lead terminal is shown in%. The numerical values in Table 1 are shown as an average of the maximum deformation amount of 18 chips.
[0070]
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 the present invention is not limited to this embodiment even if there is a design change within a scope not departing from the gist of the present invention. included.
[0071]
Furthermore, according to the manufacturing method of the present invention, even when the manufacturing process is inlined and the semiconductor device manufacturing process is fully automated, the sealing process can be performed inline.
[0072]
【The invention's effect】
As described above, according to the present invention, the flow direction of the molten resin in the sealing member is a direction substantially orthogonal to the sealing member, and the resin is uniformly melted and the resin to be flowed. Due to the small amount, the flow rate of the molten resin around the sealing member may be low, and even if the sealing member is loaded with a very fine wire, no wire flow occurs. Practical use that can provide a sealing molding apparatus capable of shortening the preheating process time after receiving the resin, shortening the molding cycle, and significantly reducing the amount of resin waste, and a method of manufacturing a resin sealing body using the same. It has a beneficial effect.
[Brief description of the drawings]
FIG. 1 is a plan view showing a main part of a lower mold of a sealing molding apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line XX of the lower mold of FIG.
FIG. 3 is an explanatory diagram showing a side surface of the sealing molding apparatus according to the embodiment of the present invention.
FIG. 4 is a view taken in the direction of arrow A in FIG. 3;
FIG. 5 is a view taken in the direction of arrow B in FIG. 3;
FIG. 6 is a view taken in the direction of the arrow C in FIG. 3;
FIG. 7 is a plan view illustrating a state of a lower mold after supply of a molten resin MR, which is one step of sealing by the sealing molding apparatus according to the embodiment of the present invention.
FIG. 8 is an explanatory diagram illustrating a state after mold clamping, which is one step of sealing by the sealing molding apparatus according to the embodiment of the present invention, with reference to a cross section.
FIG. 9 is an explanatory view illustrating a compression molding step, which is one step of sealing by the sealing molding apparatus according to the embodiment of the present invention, with a cross section.
FIG. 10 is an explanatory diagram illustrating a state in which the lower mold 1 is opened with a plane, for explaining the shape of the molded product molded according to FIG. 9;
FIG. 11 is an explanatory diagram for explaining a demolding step which is one step of sealing by the sealing molding apparatus according to the embodiment of the present invention.
FIG. 12 is an explanatory diagram illustrating a step of sealing by a conventional sealing molding apparatus with a cross section.
FIG. 13 is an explanatory view illustrating a sealing step by a conventional sealing molding apparatus in cross section.
[Explanation of symbols]
1: Lower block
2. Upper block
3. Molding plunger
3a: Tip surface
4: Cavity molding part (mold part)
4a ... Bottom
4b ... side surface
5 ... penetrating part
6 ... Advancing and retreating
7 Resin receiving part
20: Resin material supply device
21 weighing unit
25… Measuring pot
31 ... Stirring unit
32 ... Stirring cup
37… Plunger
37a… Stirring rod
41 ... Supply unit
45 ... Motor for vertical movement
51: Mobile unit
52 ... Moving motor
61 ... Molding mold (lower mold)

Claims (2)

A molding apparatus having a mold clamping mechanism and an advancing / retracting mechanism of a molding plunger, wherein a lower mold cavity portion is formed with a resin receiving portion for receiving a sealing resin at an upper portion of a tip surface in a state where the molding plunger is retracted, In the state in which the molding plunger is advanced, a molding plunger for compression molding in which the tip surface forms the bottom molding surface of the lower mold cavity while compressing the sealing resin supplied to the resin receiving portion and is molded so as to be movable forward and backward. Lower mold,
A mold composed of the lower mold and an upper mold that can be clamped by a mold clamping mechanism,
A sealing supply device that supplies a sealing resin that has been stirred and melted to the resin receiving portion when the mold is opened. Using the device according to claim 1,
(A) a resin supply step of supplying a resin for sealing to a resin receiving section in a state where the mold is opened,
(B) a mold clamping step of clamping the upper mold and the lower mold by the mold clamping mechanism;
(C) a compression molding step in which the tip surface of the molding plunger is raised to the molding surface, and the semiconductor device is sealed and cured with the molten resin received in the resin receiving portion;
(D) A method for manufacturing a resin-sealed body, which comprises sequentially performing a demolding step of opening a mold and taking out the obtained resin-sealed body.

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