JPH08250533A - Manufacture of semiconductor package - Google Patents

Abstract

PURPOSE: To prevent the deformation or disconnection of wire-bonded sections of a semiconductor device which is caused by the fact that the wire-bonded sections are brought into contact with films when a semiconductor package is manufactured using a pair of films. CONSTITUTION: In cavity surfaces 1a of a die which are to be located face to face with circuit faces of semiconductor devices 13, suction holes 1b are preliminarily formed with one end being led to the inside of cavities 3 and the other end being connected to a suction source outside the die 1. Then, films 21, 22 are set in a pair of dies 1, 2 respectively. By sucking the cavities 3 from outside the die 1 through the suction holes 1b, parts of the film 21 which are to be circuit faces of the semiconductor devices 13 are sucked to the corresponding cavity surfaces 1a of the die 1. Then, the semiconductor devices 13 and sealing material 14 are set between the films 21 and 22 and after that, the dies 1, 2 are closed and the sealing material 14 is pressed to be injected into the cavities 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor package which is obtained by sealing a semiconductor device with a resin.

[0002]

2. Description of the Related Art As a method of sealing a semiconductor device such as a chip-like LSI with a resin and packaging it, there is a method by transfer molding. In this method, powdered or tablet-shaped resin is heated and pressurized to melt it, then it is poured into a mold and solidified to be packaged. According to this, the resin can be injected into the mold at a low speed. By doing so, it is possible to mass-produce semiconductor packages of constant quality at a relatively low cost. Therefore, as a resin sealing method for semiconductor devices, the transfer molding method has been most often used conventionally.

However, with the recent demand for lower prices of semiconductor devices, it has become necessary to greatly improve productivity in the field of resin sealing of semiconductor devices as described above. In that case, in the conventional transfer molding method, it is necessary to frequently clean the mold that has become dirty due to the adhesion of the resin that is the sealing material, and after the molding, the eject pin is ejected from the mold to form a semiconductor package. There is a risk that the semiconductor device may be damaged when the mold is released, and that the mold cost is high due to the fact that such a mold for ejecting eject pins must be provided. Therefore, the inventors of the present application have proposed the following semiconductor package manufacturing method as a technique capable of solving these problems and greatly improving productivity.

That is, when manufacturing a semiconductor package in which a semiconductor device is sealed with resin, the semiconductor device and the sealing material are set on a mold for molding the semiconductor package in a state of being inserted between a pair of upper and lower films. The mold is closed, and then the sealing material between the films is pressurized and heated to be injected into the mold cavity to seal the semiconductor device. According to this, the semiconductor package can be molded without directly contacting the mold cavity surface with the resin as the sealing material, so that the mold does not become dirty and the semiconductor package held between the films after molding is Since the same film can be easily separated from the mold, there is no need for an eject pin. Therefore, it is possible to significantly improve the continuous moldability by reducing the number of times of cleaning the mold, reduce the cost of the mold by eliminating the need for the eject pin, and thereby significantly improve the productivity.

[0005]

By the way, in the above method, a so-called wire-bonded semiconductor device which is electrically connected to the lead frame in advance through a thin connecting wire (usually a gold wire) is used. Although it is used, it has been found that the following problems may occur when the semiconductor device of this type is sealed by the above method. That is, when the semiconductor device and the sealing resin are set on the mold via the one film and then the other film is covered on the mold, the connection line connecting the circuit of the semiconductor device and the lead frame is It has been found that the film may be deformed or broken due to contact with a film located on the circuit surface of the semiconductor device.

The present invention addresses such a problem, and when a semiconductor package is manufactured using a pair of films, it prevents contact between the semiconductor device and the film set on the circuit surface side thereof. It is an object of the present invention to avoid the deformation and disconnection of the connection line and to improve the reliability in the manufacturing process of the semiconductor package.

[0007]

In order to achieve the above object, the present invention provides a semiconductor device and a sealing material on a semiconductor package molding die when manufacturing a semiconductor package in which a semiconductor device is resin-sealed. , The mold is closed, the mold is closed, and the sealing material between the two films is pressed and heated to inject it into the mold cavity to seal the semiconductor device. A method of manufacturing a semiconductor package for stopping is characterized by being configured as follows.

That is, a suction hole having one end communicating with the cavity and the other end connected to a suction source outside the mold is previously provided on the mold cavity surface side facing the circuit surface of the semiconductor device. Prior to the insertion of the semiconductor device between the pair of films, the film to be set on the circuit surface side of the semiconductor device is accommodated by sucking the inside of the cavity from outside the mold through the suction hole. Then, the semiconductor device and the sealing material are set between the pair of films, and the mold is closed.

Here, as a means for preventing the film adsorbed on the die cavity surface side from being pressed against the suction hole and broken by the pressure applied at the time of package molding, the surface of the film located on the semiconductor device side. A heat resistant material layer having heat resistance capable of withstanding the temperature at the time of molding the package and predetermined strength may be provided on (a surface located on the side opposite to the surface in contact with the suction hole).

As the film used in the present invention, the tensile strength at high temperature (175 ° C.) in the sealing step is 0.
A film having a weight ratio of 5 to 15.0 kgf / mm ² and an elongation at high temperature of 200% or more in both the extrusion direction and the right angle direction is preferable. In this case, the tensile strength and elongation at 175 ° C are JISC
It is the value measured according to 2318. The reason for recommending such a film is as follows. That is,
At the time of injecting / filling the sealing material into the cavity, the pressure of the film causes the pair of films to follow the irregularities of the inner surface of the mold, that is, the irregularities of the runner part, the gate part, and the cavity. Since the tensile force according to the uneven shape and the injection pressure of the sealing material acts, if the film does not stretch according to the tensile force, it may not be able to follow the unevenness and may be broken. This is because if the film has the above-mentioned tensile strength and elongation, it will stretch according to the tensile force without breaking and will follow the predetermined state on the cavity surface.

The material of the film used in the present invention is, for example, polyethylene terephthalate (PE
T), polybutylene terephthalate (PBT), polystyrene (PS), polytetrafluoroethylene (PTF)
E), nylon, etc. can be mentioned. Further, the thickness of the film is arbitrary as long as it has the above-mentioned performance, but generally, a film having a thickness of 6 μm to 1 mm can be used. In addition, in order to improve the releasability from the sealing material, the film surface may be subjected to a releasing treatment.

The material constituting the above-mentioned heat-resistant material layer has heat resistance and strength (preferably a tensile strength at 175 ° C of 2 at the molding temperature (usually 150 to 200 ° C)).
0 kgf / mm ² or more: Any value as long as it has a value measured according to JIS C2318). Specifically, a polyimide film, an aluminum foil, etc. can be mentioned. The thickness of this type of heat resistant material is usually 6 to 100.
μm is preferred. Such a heat-resistant material is provided with a heat-resistant adhesive or adhesive at a predetermined position of the film set on the circuit surface side of the semiconductor device, that is, a suction provided on the mold cavity surface side when the film is set. It is provided at a position that covers one end of the hole. In this case, the heat resistant material may be provided on either the cavity surface side of the film or the semiconductor device side. However, if it is provided on the semiconductor device side surface, the heat resistant material is transferred to the package surface during molding of the semiconductor package. It is also preferable because it can also be used as a transfer material (package coating material) during molding, and the coating of the heat-resistant material can improve the package performance.

[0013]

According to the above structure, prior to the setting of the semiconductor device on the mold, the semiconductor device is exposed from the outside of the mold through the suction hole on the mold cavity surface side, which is positioned to face the circuit surface of the semiconductor device. By sucking the inside of the cavity, the film to be set on the circuit surface side of the semiconductor device is sucked on the suction hole side cavity surface. As a result, the adsorbed film portion is deformed so as to follow the shape of the cavity surface, and a recess corresponding to the shape of the cavity surface is formed on the film. Therefore, by setting the semiconductor device and the sealing material between the pair of films on the mold so that the circuit surface side of the semiconductor device is located on the concave side,
It is possible to avoid the contact of the connection line connecting the circuit of the semiconductor device and the lead frame with the film. This can prevent the connection line from being deformed or broken due to contact with the film.

In this way, after the semiconductor device and the sealing material are set on the mold in a state of being inserted between the pair of films, the mold is closed, and in that state, the sealing material between both films is closed. Is pressurized and heated and injected into the mold cavity to mold the semiconductor package. In that case, there is a risk that the film portion located at one end of the suction hole on the cavity surface side is pushed toward the hole side by the pressure during molding and is broken. However, if a heat-resistant material layer having predetermined heat resistance and strength is provided in advance at a predetermined position of the film located on the circuit side of the semiconductor device so as to cover one end of the suction hole, the heat-resistant material layer sucks the heat. The film portion around the hole is reinforced, and the pressure at the time of molding is directly received by the heat resistant material layer. As a result, it is possible to prevent the portion of the film on the circuit side of the semiconductor device corresponding to the suction hole from breaking due to the pressure applied during molding.

[0015]

Embodiments of the present invention will be described below. First, the semiconductor package manufacturing apparatus used in this embodiment will be briefly described.

As shown in FIG. 1, this semiconductor package manufacturing apparatus has a pair of upper and lower molds 1, 2 which can be opened and closed and which are attached to a transfer molding machine (not shown). In these molds 1 and 2, there are provided a plurality of cavities 3 ... 3 for molding a semiconductor package, and a pot 4 having a circular concave shape which communicates with the cavities 3 and in which a sealing material (resin) described later is set. Is formed, and each mold 1, 2 is formed at the time of molding.
A heater (not shown) is provided for heating each to a predetermined temperature. Here, a plunger 5 for pressurizing the sealing material is provided in the pot portion 4 of the lower mold 2 so as to be vertically movable.

In addition, the upper die 1 is provided with cavity surfaces 1a which are to be opposed to a circuit surface of a semiconductor device described later.
A plurality of suction holes 1b ... 1b are provided on the side. In the illustrated example, these suction holes 1b ... 1b are formed in the same mold 1 from the cavity surface 1a of the upper mold 1 toward the upper surface 1c.
It is configured to penetrate. Then, the end of the suction hole on the upper die upper surface 1c side is connected to an external suction source (for example, a suction pump) not shown, and the cavity 3 side is moved from the external suction source side via each suction hole 1b. By sucking, the first mold surface 1a of the upper mold 1 will be
The film 21 can be adsorbed.

Next, the method of this embodiment carried out using such an apparatus will be described. First, as shown in FIG. 1, with the upper and lower molds 1 and 2 opened, the first and second films corresponding to the respective molds 1 and 2 (on this cavity surface 1a, 2a side) In the example, PTFE films 21 and 22 having a thickness of 40 μm are set in predetermined states. In this case, the first film 21 has a heat-resistant adhesive layer (in this example, a heat-resistant adhesive layer) capable of withstanding a molding temperature (usually 150 to 200 ° C.) at a predetermined position facing a circuit surface of a semiconductor device described later. A heat-resistant material layer (in this example, an aluminum foil having a thickness of 15 μm) of a predetermined strength that can withstand the molding temperature via an epoxy resin layer 23 having a thickness of 10 μm) 24
In advance.

Next, as shown in FIG. 2, the cavity 3 side is sucked from an external suction source through the suction holes 1b provided on each cavity surface 1a side of the upper mold 1. By doing so, in the first film 21, the film portion corresponding to the cavity surface 1a of the upper mold 1 is formed in the same cavity surface 1a.
Is adsorbed by the cavity surface 1a
The concave portion 1a 'is formed according to the shape of Therefore, in this state, on the second film 22 on the lower mold 2, the wire bond portion (connection wire) 1 made of a gold wire is formed on the lead frame 11.
The semiconductor device 13 connected and fixed via 2 and the sealing material 14 are set. At this time, the semiconductor device 13 is set such that its circuit surface (upper surface in the illustrated state) faces the heat-resistant material layer 24 in the recess 1a ′, and the sealing material 14 is set in the lower mold 2. Set so that it is located above the pot portion 4.

Next, as shown in FIG. 3, the upper and lower molds 1 and 2 are closed. When the molds 1 and 2 are closed in this manner, the sealing material 14 is positioned in the pot portion 4 while being sandwiched between the films 21 and 22, but the second film 22 is used.
The circuit surface side of the upper semiconductor device 13 is the first film 21.
The heat-resistant material layer 24 on the side is opposed to the heat-resistant material layer 24 with a certain space.

Next, from this state, the plunger 5 is pushed up to pressurize the sealing material 14 in the pot portion 4 to plasticize the sealing material 14 as shown in FIG. The space between the films 21 and 22 is filled in each cavity 3.

After the cavity 3 is filled with the sealing material 14 in this way, after the material is cured, the molds 1 and 2 are opened as shown in FIG. Semiconductor device 13, that is, semiconductor package 15
After taking out both films 21 and 22, both films 21 and 22 are peeled off from the package surface, and unnecessary molding portion 16 is cut as shown in FIG. As a result, as shown in the figure, a semiconductor package 15 in which the semiconductor device 13 is sealed with the resin 14 ′ formed of the sealing material 14 and the heat resistant material layer 24 is transferred to the surface is obtained.

According to such a method, when the semiconductor device 13 is set at a predetermined position on the lower mold 2 through the second film 22, as shown in FIG.
The predetermined portion of the first film 21 located on the side is sucked from the outside through each suction hole 1b in the upper mold 1 and is adsorbed to the cavity surface 1a of the mold 1, so that the first film 21 A recess 1a 'corresponding to the shape of the cavity surface 1a is formed in the predetermined portion. Therefore, when setting the semiconductor device 13 between the two films 21 and 22,
By arranging the circuit surface side of the semiconductor device 13, that is, the wire bond portion 12 side, in the concave portion 1a ′ so as to face each other, the wire bond portion is set when the semiconductor device 13 is set on the lower mold 2 and then the mold is closed. 1st film 2 on 12
It is possible to avoid the contact of one. As a result, the wire bond portion 12 is prevented from being deformed or broken during the manufacture of the semiconductor package.

By the way, when the first film 21 is attracted to the cavity surface 1a through the suction holes 1b provided on the cavity surface 1a side of the upper mold 1 as described above,
Due to the pressure applied to the sealing material 14 in the pot portion 4 via the plunger 5 at the time of molding, the film portion near the opening end of each suction hole 1b on the cavity 3 side may be broken. However, in this embodiment, the heat-resistant material layer 24 having a predetermined heat resistance and strength is provided on the surface of the first film 21 that is adsorbed to the cavity surface 1a on the side facing the circuit surface of the semiconductor device 13. However, even if pressure is applied during molding, the heat-resistant material layer 24 can reliably prevent breakage of the film portion near the suction holes as described above. Moreover, when the semiconductor package 15 is molded by injecting the sealing material 14 into the cavity 3, the above-mentioned heat resistant material layer 24 is transferred to the surface of the package. It is possible to improve the heat resistance and the like of the semiconductor package 15.

[0025]

As described above, according to the present invention, in a method of manufacturing a semiconductor package in which a semiconductor device and a sealing material are inserted between a pair of films, the semiconductor device is mounted on a package molding die. Before setting, the film that will be located opposite to the circuit surface is adsorbed to the corresponding mold cavity surface, so that the connection line that connects the semiconductor device and the lead frame, that is, the wire bond portion, is the same film. It is possible to avoid contact with. As a result, the deformation and disconnection of the wire bond portion are surely prevented, and the reliability in this type of semiconductor package manufacturing method is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing one step in an embodiment method of the present invention, in which a pair of films are set on corresponding mold surfaces in a state where the mold is opened.

FIG. 2 shows a state in which one film, which will be positioned to face the circuit surface of the semiconductor device, is adsorbed to the corresponding mold cavity surface, and then the semiconductor device and the sealing material are set on the other film. Cross section

FIG. 3 is a sectional view showing a state in which the mold is closed after the setting.

FIG. 4 is a cross-sectional view showing a state in which the sealing material is then pressurized and filled in the cavity.

FIG. 5 is a cross-sectional view showing a state in which each film is peeled from the surface of the semiconductor package taken out of the mold after molding.

FIG. 6 is a sectional view showing a finally obtained semiconductor package.

[Explanation of symbols]

1, 2 ... Mold for molding semiconductor package (1 ... Upper mold, 2 ... Lower mold) 1a ... Mold cavity surface 1b ... Suction hole 3 ... Cavity 13. ..Semiconductor device 14 ... Encapsulating material 21, 22 ... Pair of films (21 ... First film, 22 ... Second film) 24 ... Heat resistant material layer

Claims (3)

[Claims] 1. When manufacturing a semiconductor package in which a semiconductor device is sealed with a resin, the semiconductor device and a sealing material are set in a state of being inserted between a pair of films on a semiconductor package molding die. In a method of manufacturing a semiconductor package for sealing a semiconductor device by closing a mold and then injecting a sealing material between the two films into a mold cavity by applying pressure and heat to the circuit surface of the semiconductor device. On the mold cavity surface side, which is to be located opposite to, a suction hole having one end communicating with the cavity and the other end connected to a suction source outside the mold is provided in advance.
Prior to inserting the semiconductor device between the pair of films, the film to be set on the circuit surface side of the semiconductor device by sucking the inside of the cavity from the outside of the mold through the suction hole corresponds to the corresponding metal. A method of manufacturing a semiconductor package, comprising: adsorbing to a mold cavity surface side, setting a semiconductor device and a sealing material between a pair of films in that state, and then closing a mold. 2. The film adsorbed on the mold cavity surface is provided with a heat resistant material layer on the surface facing the circuit surface of the semiconductor device. Manufacturing method of semiconductor package. 3. The heat resistant material layer is a transfer material during molding which is transferred to the surface of a semiconductor device when the semiconductor device is sealed with a sealing material to manufacture a semiconductor package. Item 3. A method of manufacturing a semiconductor package according to item 1 or 2.