JP3241553B2 - Resin molding device using release film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding apparatus using a release film for resin molding of a semiconductor device.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional example of a lead frame transfer molding apparatus. In the figure, reference numerals 10a and 10b denote upper and lower dies for clamping and molding a molded product. In a conventional resin molding apparatus, the resin pressure-fed from the pot 12 directly forms the upper and lower dies 10a and 10b. Since the mold comes into contact with the surface, the mold must have a predetermined wear resistance, and a steel material (for example, alloy tool steel SKD11) is used as a material of the mold.
In addition, since the mold resin is directly in contact with the inner surface of the cavity 14 and is molded, the mold is opened and the mold is released by the ejector pins 16. Since a thermosetting resin such as an epoxy resin or a phenol resin is used for the molding resin, it is necessary to heat the molding die to a predetermined temperature, and a heater is installed in a die base for fixing and supporting the molding die. are doing.

[0003]

As described above, in the conventional resin molding apparatus, since the mold is made of steel, the heat conductivity of the mold is smaller than that of copper or aluminum. However, there is a problem that the index time of the resin mold cannot be increased in order to take time for curing the mold resin. Further, since a large number of ejector pins 16 for releasing the resin molded product are provided in the mold, the structure of the mold becomes complicated, and the heater 6 cannot be installed in the cavity block. Is Chase Block 8
Therefore, there was a problem that the temperature of the cavity block could not be accurately controlled.

The present invention has been made in view of these problems, and an object of the present invention is to make it possible to use a material having a high thermal conductivity such as copper or aluminum as a material for a mold. It enables efficient resin molding and also enables temperature control of the mold dies, thereby enabling suitable resin molding according to the product and improving the moldability of the product. An object of the present invention is to provide a resin molding apparatus using a release film that simplifies the structure of a mold and facilitates the production of a mold.

[0005]

The present invention has the following arrangement to achieve the above object. That is, the resin molding portion of the molding die is covered with release film be easily peeled off the mold and molded resin, click to be molded article
Pump resin from pot to cavity while ramping
In a resin molding apparatus using a release film for resin molding , the cavity and the like of the molding die are used.
Whether the wear resistance of the portion constituting the resin molded portion is lower than that of a material such as a steel material constituting the base portion of the mold .
One thermal conductivity different separate member, characterized in that is embedded rare. In addition, the cavity concave portion of the mold
The release film clamps on the bottom through the suction holes.
Release the film with the air suction
A cavity suction hole for air suction is opened on the inner surface of the tee recess
It is characterized by being provided . In addition, the separate part
The material is higher than the material forming the base of the mold
It is characterized by being formed of a material having thermal conductivity . Further, the separate member forms a base portion of a mold.
Formed of a material with lower thermal conductivity than the material
And said that you are. In addition, resin molding of the mold
The part is easily separated from the mold and the mold resin
Cover with a release film, clamp the workpiece
While the resin is pumped from the pot to the cavity,
Molding machine using release film
Forming the resin molded portion of the mold die
The bottom of the cavity forming the bottom of the resin molded part
Part is provided, and the cavity bottom piece is formed by molding.
Element with a higher thermal conductivity than the material that
It characterized in that it is formed by wood. Also,
Mold for the upper and lower molds
The base is made of materials having different thermal conductivity . Further, the gate portion to contact the cavity of the mold, the gate member formed of a material of low thermal conductivity than material of the installation constituting the base portion
It is characterized by having been done. Also, a heater with a built-in thermocouple for temperature control is installed inside a member constituting a resin molding portion of the mold. Also,
The surface of the resin molded portion of the mold is matte or mirror-finished, or a mark is formed.

[0006]

Since the resin molding apparatus according to the present invention performs resin molding using a release film, a mold material such as copper or aluminum is used as a material for the mold.
More wear-resistant than steel and other materials that make up the base of the mold
Inferior materials that could not be used conventionally can be used, thereby improving the index time of the resin mold and improving the moldability of the resin molded product. This also makes it possible to perform precisely temperature control of the molding die, by controlling the heating temperature of the upper and lower molds appropriate to improve the filling property of the resin in the cavity, also within the cavity It is possible to improve the injectability of the resin into the resin.

[0007]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a configuration of a transfer molding device for sealing a semiconductor resin and a method of resin-molding a lead frame 20 using the resin molding device as an embodiment of a resin molding device using a release film. The figure shows a lead frame 2 which is a molded product in the left half from the center line.
0 shows a state where 0 is clamped and a state where the cavity 14 is filled with resin in the right half.

The upper mold 10a and the lower mold 10b are provided with cavity recesses for resin molding. In this embodiment, a steel material is used as a base material of the upper mold 10a and the lower mold 10b, and the cavity recesses serving as resin molding portions are formed. The cavity bottom pieces 22a and 22b constituting the bottom are manufactured using a material having good heat conductivity such as copper, aluminum, or an alloy thereof other than steel. The clamp surfaces of the upper mold 10a and the lower mold 10b that come into contact with the molded product and the inner surface of the cavity recess are formed of steel.

The use of a material having good heat conductivity, such as copper or aluminum, as the cavity bottom pieces 22a and 22b allows effective heat exchange between the resin filled in the cavity 14 and the mold. ,
This is to speed up the curing of the resin.
The upper die 10a and the lower die 10b are used for heating the upper die 10a and the lower die 10b.
a, 26b, respectively, but in the embodiment, a heater 24 with a built-in thermocouple is further installed inside the cavity bottom pieces 22a, 22b. This allows the cavity bottom pieces 22a, 22b to be effectively heated.

[0010] The culpiece 30 provided on the upper die 10a at a position facing the pot 12 is also formed of a material having good thermal conductivity such as copper or aluminum. A heater 32 with a built-in thermocouple is also installed inside the culpiece 30, so that the temperature of the culpiece 30 can be directly controlled. The culpiece 30 is also a cavity bottom piece 22a, 2
It is installed in the upper mold 10a as in 2b. The pot 12 and the plunger are made of copper and have a built-in heater.

By the way, copper or aluminum is inferior to steel in terms of abrasion resistance. Therefore, in the case of a normal resin molding method, a material such as copper or aluminum is insufficient as a material for a molding die in terms of abrasion resistance. It is not appropriate to use In the present embodiment, the cavity bottom piece 22a,
The material that cannot be used in the conventional device in terms of wear resistance, such as copper or aluminum material, can be used for the 22b and the culpiece 30 in the present device because the release film 40 is used for resin molding. Depending on.

The resin molding method using the release film 40 is a method in which a resin contact portion on a mold surface is covered with the release film 40 during resin molding and the resin molding is performed. The release film 40 is made of a material having heat resistance to withstand the mold temperature during resin molding and a material that can be easily peeled from the mold resin and the mold.

When resin molding is performed using the release film 40, first, the release film 40 is sucked and supported by the clamp surfaces of the upper mold 10a and the lower mold 10b.
After adsorbing the release film 40 following the concave portions of the cavities of the upper mold 10a and the lower mold 10b, the lead frame 20, which is a molded product, is clamped and the cavity is filled with resin. In the embodiment, suction holes 42 for sucking the release film 40 are opened on the clamp surfaces of the upper mold 10a and the lower mold 10b, and the suction holes 42 communicate with suction channels 44 provided in the support blocks 50a and 50b for mounting the molds. Let me.

FIG. 2 shows a planar arrangement of the suction holes 42 provided on the clamp surface of the upper die 10a. A plurality of suction holes 42 are arranged at predetermined intervals within the width in which the release films 40a and 40b are arranged. Further, in order to adsorb the release film 40 along the inner surface shape of the cavity concave portion, the cavity adsorption hole 46 is opened along the peripheral edge of the bottom surface of the cavity concave portion. FIG. 2 shows a state in which the cavity suction holes 46 are opened in a slit shape.

The cavity suction hole 46 is formed as a flow path by providing a gap at the boundary between the outer surfaces of the cavity bottom pieces 22a and 22b and the base material of the mold.
Cavity suction holes 46 are also provided on suction blocks 48 provided in support blocks 50a and 50b on the back side of upper mold 10a and lower mold 10b.
Communicate with The suction channel 44 and the suction channel 48 communicate with external vacuum suction devices A and B. The cavity bottom pieces 22a and 22b are supported by the support blocks 50a and 50b in accordance with the positions of the cavities of the upper mold 10a and the lower mold 10b.
And secure them with bolts.

[0016] These release films 40 are
(a) The operation of setting the release film 40 in the mold by the mechanism for adsorbing to the lower mold 10b and performing resin molding is as follows. First, with the mold open, the release film 40 is pulled out in the same direction as the longitudinal direction of the lead frame 20 as shown in FIG. 2, and is suction-supported by the suction holes 42 on the respective mold surfaces of the upper mold 10a and the lower mold 10b. Is done. In this suction support, the release film 40 is sucked only by the suction holes 42.

Next, when the release film 40 is sucked from the cavity suction holes 46, the portion of the release film 40 that has been sucked by the clamp surface remains as it is, and the portion that covers the cavity recesses is suctioned by the cavity suction holes 46. It is adsorbed so as to stick to the inner surface. As described above, the release film 40 is made of a material that is slightly stretched by suction by the cavity suction hole 46 and is suction-supported in the shape of the cavity concave portion. The state shown in FIG. 1 is a state where the release film 40 is sucked according to the shape of the cavity concave portion.

The resin molding apparatus of this embodiment covers the resin molding surface of the mold with the release film 40 as described above so that the resin does not come into direct contact with the mold, but is supplied from the pot 12. The resin is prevented from directly contacting the mold even at the portion of the resin path connecting the culpiece 30 or the pot 12 and the cavity 14. That is, in the resin molding apparatus of the embodiment, unlike the conventional method of simply putting a resin tablet into the pot 12, the wrapping resin 5 in which the resin 52 is sealed with a film having the same heat resistance as the release film 40 is used.
4 is set in the pot 12 and resin-molded. In addition,
As the resin 52, an extruded resin before pulverization is used.

FIG. 1 shows a state of resin molding using a lapping resin. FIG. 3 shows an enlarged view of a portion where a lapping resin 54 is set. The wrapping resin 54 includes a lower wrapping film 56 having a pocket portion 56a for accommodating the resin 52, and a lower wrapping film 56.
Is formed by an upper wrapping film 57 that seals the resin 52 in the pocket portion 56a. The pocket portion 56a is formed in a shape and size that can be inserted into the pot 12, and the lower wrapping film 56 and the upper wrapping film 57 are attracted to the upper mold 10a and the lower mold 10b when the lapping resin 54 is set in the pot 12. The width of the release film 40 supported is set so as to overlap with the side edge.

The lower wrapping film 56 and the upper wrapping film 57 are adhered to each other at the overlapped portion and hermetically sealed. The lower wrapping film 56 is formed so that the film can be peeled off by the resin pressure when the resin 52 is fed from the pot 12. In the resin path, the cavity 14 is filled with resin so that the lower wrapping film 56 and the upper wrapping film 57 are pushed apart. The molten resin is composed of a lower wrapping film 56 and an upper wrapping film 57.
Between the lead frame 20 and the release film 40 adsorbed to the upper mold 10a and the lower mold 10b. The lower wrapping film 56 and the upper wrapping film 57 must be positioned in the middle. In the embodiment, since the gate 10c is arranged on the lower die 10b, the upper wrapping film 57 and the lower wrapping film 56 are arranged below the lead frame 20.

FIG. 3 shows a state in which the cavity 10 is filled with resin from the gate 10c in the right half of FIG. When the resin 52 is extruded from the pot 12, the resin 52 can be pressure-fed without being adhered to the inner wall surface of the pot 12 or the plunger 13 by pushing the resin 52 with the plunger 13 while being sealed with a wrapping film. The resin pressure-fed from the pot 12 spreads the lower wrapping film 56 and the upper wrapping film 57 along the gate 10c, and is guided to the cavity 14 to be filled. The resin pressure-fed from the pot 12 is fed without directly contacting the molding die even in the resin path portion such as the culpiece 30 and the gate 10c.

FIG. 2 shows a plan view of the pot 12 and the pot 12.
2 shows a planar arrangement of a gate 10c that communicates with each cavity. In the resin molding apparatus of the embodiment, the pot 12 is formed in a planar shape and an elongated shape, and is disposed in the middle of a setting position where the lead frame 20 is set to face the same and parallel to the longitudinal direction of the lead frame 20. Resin 52 is pot 12
Used in the form of an elongated stick according to the shape of The runner path connecting the pot 12 and each cavity 14 and the gate 10c are arranged so that the branch path extends from the pot 12 to both sides. Plunger 1
The end 3 has an elongated shape in conformity with the shape of the pot 12, and the resin is pumped by the plunger 13 to fill the cavity from each gate 10c.

FIG. 2 also shows an air vent groove 60 provided on the clamp surface of the mold. The air vent groove 60 is formed so as to be connected to a corner portion of the cavity concave portion, to be connected to an end portion of an air vent portion 60a provided on the clamp surface, and to extend to a side edge of the mold. Since the lead frame 20 is clamped via the release film 40, it does not directly contact the clamp surface of the mold. However, by providing the air vent portion 60a on the mold surface, the air vent can be performed via the release film 40. .

In the resin molding apparatus using the release film according to the present embodiment, the resin molding surfaces of the upper mold 10a and the lower mold 10b are covered with the release film 40 and resin-molded, so that the resin is brought into direct contact with the mold. There is a great feature different from the conventional device in that the resin molding can be performed without using a resin. Since the resin can be molded without the resin coming into direct contact with the mold in this way, the range of materials that can be used as the material for the mold is expanded,
It becomes possible to use materials such as copper or aluminum, which could not be used conventionally. Also, the use of the release film 40 makes it very easy to release the product from the mold, so that it is not necessary to install an ejector pin on the mold, thereby simplifying the structure of the mold. it can.

As described above, by using a material having a high thermal conductivity such as copper or aluminum as the material of the mold, heat exchange with the resin can be promoted, and the curing time of the resin can be increased and the index time of the resin mold can be increased. Can be improved. The material used for the mold and the thermal conductivity of copper are exemplified. Ni-Cr
Steel k = 37 W · m ⁻¹ · K ⁻¹ (180 ° C.), 18-8 stainless steel k = 18 W · m ⁻¹ · K ⁻¹ (180 ° C.), carbon steel for general structural use k = 47 W · m ⁻¹ · K ^-1 (180 ℃), iron k = 65W
· M ^-1 · K ^-1 (180 ° C), copper k = 385 W · m ^-1 · K ^-1
(180 ° C). In addition, since the ejector pins do not need to be provided in the mold, the heater 24 with a built-in thermocouple can be built in the cavity bottom pieces 22a and 22b as shown in FIG. , 22b can be controlled by directly heating the resin.

As described above, according to the resin molding apparatus of the present embodiment, the configuration in which the heater 24 with a built-in thermocouple is incorporated in the molding die can be adopted, and the material selection range of the molding die is expanded. Therefore, the temperature of the mold can be controlled more accurately than in the conventional apparatus. The technology for controlling the temperature of the mold is to control the curing speed of the resin filled in the cavity, to make it easier to fill the cavity with the resin, and to control the progress of curing when the resin is cured in the cavity. Get involved.

That is, in the case of the above embodiment, the control is such that the thermosetting is accelerated and the index time is improved by forming the cavity bottom pieces 22a and 22b from a material having a high thermal conductivity.
It is conceivable to improve the filling property of the resin into the cavity 14 by changing the progress of the thermosetting between the a and the lower mold 10b. For example, as shown in FIG. 4, when the gate is in the lower mold 10b in a product in which the semiconductor chip is mounted on the lower side of the lead frame 20, the resin injected into the cavity 14 is hardly cured by the lower mold 10b. Upper die 10a
The temperature of the lower mold 10b is increased so that the
It is possible to perform control such that it is set slightly lower than 0a.

Such a temperature control is applied to one side of the package when an extremely thin product is molded with a resin and the filling of the resin in the cavity becomes a problem or when the thicknesses of the upper and lower packages are different. It can be suitably applied to a case where a heat sink enters. As a method of controlling the heating temperature by changing the upper mold 10a and the lower mold 10b as described above, a method of controlling the heating temperature by the heater 24 with a built-in thermocouple, and a method of controlling the heating temperature by the upper mold 10a and the lower mold 10b
For example, a method of generating a temperature difference by using materials having different thermal conductivity is possible.

As another method for improving the filling property of the resin in the cavity, as shown in FIG. 5, the gate portion which is melted when the resin is filled into the cavity has a higher thermal conductivity than the material constituting the cavity. It is also possible to improve the injectability of the resin from the gate by installing a gate member 64 made of a low-grade dissimilar material. This method is intended to prevent the resin from hardening when passing through the gate member 64 so that the resin can be injected well. By placing the gate member 64 insulated from the other parts, the temperature can be lowered more than the other parts of the mold. Further, by forming the resin path portion for filling the cavity with the resin with a different material, it is possible to improve the flowability of the resin in the resin path and to improve the filling property of the resin.

As described above, as an example of using the method of controlling the temperature of the mold by combining different materials in each of the upper mold 10a and the lower mold 10b, a semiconductor chip is mounted on the lead frame 20 as shown in FIG. There is a method of disposing a different material 66 having a higher thermal conductivity than other portions or a lower thermal conductivity than other portions in a mold corresponding to positions. In this case, it is preferable to use a material having a lower thermal conductivity than the other parts as the different material 66, because the gap in the cavity is narrow at the part where the semiconductor chip is mounted in a thin product, There is a method of use in which the flowability of the resin in this portion is improved and the filling property of the resin in the entire cavity is improved.

In a case where it is preferable to use a material having high thermal conductivity as the different material 66, the resin is hardened at the center of the cavity so that the resin is sealed during or after the resin is hardened. There is an effect that the part can be prevented from warping. FIG. 5 shows the dissimilar material 66 in FIG.
Is also shown, but the dissimilar material 66 does not necessarily have to be installed at the center of the cavity, and a plurality of dissimilar materials 66 can be arranged. Instead of using the dissimilar material 66, it is also possible to control the temperature by incorporating a heater so that a temperature change occurs partially in the mold.

In the method of the present invention, the resin molding is performed while the resin molding surface of the mold is covered with a release film. The surface condition of the mold surface of the mold is transferred to the product via the release film. Therefore, when the mold surface of the product is matte, the mold surface of the mold may be matte, and when the mold surface is mirror, the mold may be mirror. Similarly, when a mark is provided on the mold surface of a product, the mark can be transferred in advance by providing a mark on the mold in advance.

As the film material used for the release film 40, those satisfying predetermined heat resistance and the like can be used. For example, FEP sheet film, PET sheet film, fluororesin impregnated glass cloth, polyvinylidene chloride and the like can be used. It is. Further, in the above embodiment, the suction hole 42 and the cavity suction hole 46 are provided in the mold in order to suck and support the release film 40 on the mold surface so that the release film 40 can be sucked. The release film 40 can be suction-supported on the resin molded portion by manufacturing a mold with high quality metal. The use of the release film 40 makes it possible to use such a porous metal in a mold.

[0034]

According to the resin molding apparatus using a release film according to the present invention, a material such as copper or aluminum, which cannot be used in a conventional molding die, can be used as a base material of the molding die. Thus, heat exchange between the mold and the resin is promoted, and the index time of the resin mold can be improved. In addition, the temperature of the mold can be precisely controlled by combining the mold with a member made of a material different from that of the base material, or by incorporating a heater into the mold and directly heating the mold. Since it is performed, there is a remarkable effect that the moldability of the resin molded article can be improved by controlling the filling of the resin into the cavity, the injection of the resin into the cavity, and the curing of the resin in the cavity. ,

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of an embodiment of a resin molding apparatus using a release film.

FIG. 2 is an explanatory view showing a planar arrangement of suction holes and the like of a mold;

FIG. 3 is an explanatory view showing a state in which a lapping resin is set in a pot of the resin molding apparatus.

FIG. 4 is an explanatory view showing an arrangement of different kinds of materials in a mold.

FIG. 5 is an explanatory diagram showing a planar arrangement in which different kinds of materials are installed in a mold.

FIG. 6 is a sectional view showing a conventional example of a resin molding apparatus.

[Explanation of symbols]

 10a Upper mold 10b Lower mold 12 Pot 14 Cavity 20 Lead frame 22a, 22b Cavity bottom piece 24, 32 Heater with built-in thermocouple 26a, 26b Heat block 30 Calpiece 40, 40a, 40b Release film 42 Suction hole 44, 48 Suction flow path 46 Cavity suction hole 52 Resin 54 Wrapping resin 56 Lower wrapping film 57 Upper wrapping film 60 Air vent groove 60a Air vent portion 66 Dissimilar material

Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 21/56 H01L 21/56 T (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 33 / 00-33/76 H01L 21/56

Claims (9)

(57) [Claims] 1. A resin molding portion of the molding die is covered with release film be easily peeled off the molding die and the molding resin, the pot while clamping the object to be molded article
In a resin molding apparatus using a release film for performing resin molding by pressure-feeding a resin to a cavity , the resin mold portion of the molding die, such as a cavity,
The steel that constitutes the base of the mold
Resin molding device using the release film abrasion resistance inferior and thermal conductivity than the material, such as wood is different separate member, characterized in that is embedded rare. 2. A bottom of a cavity of the mold.
The release film is clamped on the surface through the suction hole
Hold the release film in a cavity with the surface adsorbed by air.
A cavity suction hole for air suction is opened on the inner surface of the recess.
The resin molding apparatus using the release film according to claim 1, wherein the resin molding apparatus is provided. 3. A separate member forms a base portion of a mold.
Formed of a material with higher thermal conductivity than the material
A resin molding apparatus using the release film according to claim 1 or 2 . 4. A separate member forms a base portion of a mold.
Formed of a material with lower thermal conductivity than the material
A resin molding apparatus using the release film according to claim 1 or 2 . 5. The method according to claim 5, wherein the resin molding portion of the mold is replaced with a mold.
Release fill that easily peels off mold and mold resin
Pot with the molded product clamped
From the resin to the cavity by pressing resin into the cavity
In a resin molding apparatus using a base film, at a portion constituting the resin molding portion of the mold,
The cavity bottom piece constituting the bottom of the resin molded part is
And the cavity bottom piece forms the base of the mold.
Formed of a material with higher thermal conductivity than the material
Resin molding device using the features and to Brighter lease films that are. 6. Used for an upper mold and a lower mold of a mold.
The bottom piece of the cavity is made of material with different thermal conductivity.
The resin molding apparatus using the release film according to claim 5, wherein the resin molding apparatus is formed by forming the resin film. 7. A gate section to contact mold cavity, the low thermal conductivity than the material constituting the base portion
Claim 1, wherein the this <br/> the gate member formed of a material is placed, a resin molding device using the release film of 2, 3, 4, 5 or 6, wherein. 8. A part constituting a resin molding part of a mold.
A heater with a built-in thermocouple for temperature control is installed inside the material.
Claim 1, 2, 3, 4, characterized in that they are,
A resin molding apparatus using the release film according to 6 or 7 . 9. The release according to claim 1, wherein the surface of the resin molding portion of the mold is matted or mirror-finished, or a mark is formed. A resin molding device using a film.