JP2597244B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device and a processing container for a semiconductor device, and more particularly to a method for preventing a semiconductor device from warping.

[0002]

2. Description of the Related Art Lead frames used for mounting semiconductor devices such as ICs and LSIs are formed into a desired pattern by pressing or etching a plate made of a metal material such as an iron or copper material. It is formed by molding.

Normally, as shown in FIG. 5, a lead frame 1 has a die pad 11 on which a semiconductor integrated circuit chip (hereinafter referred to as "semiconductor chip") is mounted, and a plurality of inner leads arranged so as to surround the die pad. A tie bar 13 for integrally connecting the lead 12 and the inner lead 12, an outer lead 14 connected to each inner lead and extending outside the tie bar, and a tie bar 13; It comprises side bars 15 and 16 for supporting from both sides, and a support bar 17 for supporting the die pad 11.

In a semiconductor device mounted using such a lead frame, a semiconductor chip 2 is mounted on a die pad 11 of a lead frame 1 and a bonding pad of the semiconductor chip is connected to the lead frame. The inner lead 12 is connected to a bonding wire 3 of a gold wire or an aluminum wire, and these are sealed with a sealing material 4 such as resin or ceramic.

[0005] Usually, after passing through a post-curing step of removing internal residual stress remaining in the resin-sealed portion in the resin-sealing step, the tie bars and side bars are cut, and the outer leads are formed as desired. It is folded into a shape and completed.

In the curing step and the post-curing step, as shown in FIG. 6, a semiconductor device 33 is stacked and stored in a semiconductor device storage magazine 31, and is held at a desired temperature while being supported by a stopper plate 32. After heating and holding in a heated atmosphere furnace for a desired time, the semiconductor device is gradually cooled and cured.

According to this method, when the semiconductor device housed in the magazine 31 is subjected to the heating and slow cooling,
Warping occurs as shown in FIG. 7 due to a difference in thermal expansion coefficient between the materials, a difference in thickness between the upper and lower portions of the resin sealing portion, and the like.

[0008] In particular, it is often found in thin semiconductor devices such as TSOP. This warpage causes a connection failure when mounting on a mounting substrate or causes cracks in a sealing resin. Was.

[0009]

As described above, in a semiconductor device formed by a conventional method, a thermal expansion between materials is performed when heating and slow cooling are performed in a curing process for removing internal residual stress. Warpage occurs due to a difference in coefficient or a difference in thickness between the upper and lower portions of the resin sealing portion, which may cause a connection failure when the surface is mounted on a mounting substrate, or cause cracks in the sealing resin. Was causing it to occur. Such inconvenience was particularly noticeable in a thin package.

The present invention has been made in view of the above circumstances, and has as its object to provide a highly reliable semiconductor device which does not warp when being made thin.

[0011]

Therefore, according to the present invention, after the package is formed by resin encapsulation, the packages are arranged, and the package surfaces located at both ends of the package are clamped by a pressure plate to apply pressure. While applying pressure to the upper and lower surfaces via a pressure plate or an adjacent package, a curing process to remove internal residual stress is performed, and the pressurized state is maintained until cooling. And That is, according to the method of the present invention, a semiconductor chip is mounted on a semiconductor chip mounting portion of a lead frame, and a semiconductor chip mounting step of making electrical connection is performed. Forming process and forming, arranging the package, holding the package surfaces located at both ends thereof with a pressure plate and applying pressure, the upper and lower surfaces of the package,
A heat treatment step in which pressure is applied through a pressure plate or an adjacent package, heat treatment is performed in a state where the package is restrained, and cooling is performed while pressing the upper and lower surfaces, and separation molding in which external leads of the lead frame are separated and molded. And a step. Further, in the semiconductor processing container of the present invention, a box-shaped magazine main body for accommodating a large number of molded semiconductor devices arranged in such a manner that their package surfaces are in contact with each other, and disposed inside the magazine main body so as to face each other. A pressure plate formed of two flat plates provided, a pressure screw for pressing the two pressure plates through an insertion hole provided in the magazine body, and a pressing state by turning the pressure screw. And an adjusting means for adjusting, wherein the heat treatment is performed while the semiconductor device is housed.

[0012]

According to the above structure, in the curing step for removing the internal residual stress, the upper and lower surfaces of the semiconductor device are sandwiched between the flat plates and heating and slow cooling are performed while applying pressure. Even if there is a difference in thermal expansion coefficient or a difference in thickness between the upper and lower portions of the resin sealing portion, no warpage occurs,
A flat and highly reliable semiconductor device can be obtained. In addition, although the thin surface mounting semiconductor device may cause cracks when pressure is applied as it is, according to the method for manufacturing a semiconductor device of the present invention, by applying pressure while adjusting the pressure with a pressing screw, a flat plate is applied to the flat plate. Since the heat treatment is performed while applying a uniform pressure and balancing the forces, the buffering action of the pressure screw makes it possible to obtain a thin semiconductor device with high yield and high reliability without cracks. It becomes possible.

Therefore, when the semiconductor device is surface-mounted on a mounting substrate, it does not cause a connection failure and does not cause cracks in the sealing resin. Further, according to the processing container for semiconductor of the present invention, it is possible to very easily perform post-curing of a large number of thin semiconductor devices at the same time,
The adjustment means may be adjusted according to the size of the semiconductor device, and handling is extremely easy. Further, the semiconductor device can be used as it is for transportation or storage as it is, and it is possible to transport and store a large number of thin and easily deformable semiconductor devices simultaneously without deformation. In addition, although the thin surface mounting semiconductor device may cause cracks when pressure is applied as it is, according to the processing container for semiconductor device of the present invention, it is possible to apply pressure while adjusting the pressure with a pressure screw, and to use a flat plate. Since the pressure is balanced by applying a uniform pressure, the yield can be improved without cracking due to the buffering action of the pressure screw.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a plan view of a semiconductor device after resin sealing, FIG. 2 is a perspective view of a main part of a magazine provided with a pressing device used in a curing process, and FIG. The state diagram attached to the magazine is shown.

This pressurizing device comprises two pressurized plates 41a and 41b, which are disposed opposite to each other inside a box-shaped magazine 42, and an insertion hole 47 provided in the magazine 42. A pressure screw 44 for pressing the pressure plates 41a, 41b through the handle, a handle 43 for turning the pressure screw to adjust the pressed state, and a frame 45 for supporting the pressure screw and the handle. .

In mounting, first, a lead frame as shown in FIG. 5 is prepared, a semiconductor chip 2 is mounted on a die pad 11 of the lead frame 1, and a bonding pad of the semiconductor chip and a lead frame are mounted. The inner lead 12 of the system is connected to a bonding wire 3 of a gold wire or an aluminum wire, and these are sealed with a sealing material 4 such as resin or ceramic.

Then, using a magazine as shown in FIG. 2, the semiconductor devices 46 are stacked and mounted as shown in FIG.
By turning the handle 43, the pressing screw portion 44 is moved, and the positions of the pressing plates 41a and 41b are adjusted so that a desired pressure is obtained. The pressure may be adjusted using a torque wrench.

In this state, it is set in a heating furnace maintained at 180 ° C., and after a curing step of removing internal residual stress remaining in the resin sealing portion in a resin sealing step and a post-curing step of cooling and hardening, Remove from the magazine with the pressure plate, cut the tie bars and side bars, and
The lead is bent into a desired shape and completed. Thus, a semiconductor device as shown in FIG. 4 is completed.

The semiconductor device thus formed is
A flat state is maintained without warpage of the package, no cracks are generated, and a good connection state can be obtained even when performing surface mounting.

It is needless to say that the shapes of the pressure plate and the magazine are not limited to the embodiments but can be appropriately modified.

[0022]

As described above, according to the method of the present invention, the upper and lower surfaces of the semiconductor device are sandwiched between the flat plates, and while the pressure is applied, the curing process is performed, and the semiconductor device is allowed to cool as it is. Therefore, a flat and highly reliable semiconductor device can be obtained without warpage. According to the semiconductor device processing container of the present invention,
The post-curing of a large number of thin semiconductor devices can be performed very easily at the same time, and the adjustment means may be adjusted according to the size of the semiconductor device, and handling is extremely easy. Further, the semiconductor device can be used as it is for transportation or storage as it is, and it is possible to transport and store a large number of thin and easily deformable semiconductor devices simultaneously without deformation.

[Brief description of the drawings]

FIG. 1 is a plan view of a semiconductor device according to an embodiment of the present invention after resin sealing.

FIG. 2 is a perspective view of a main part of a magazine provided with a pressurizing device used in a curing process according to the embodiment of the present invention.

FIG. 3 is a diagram showing a state where the semiconductor device of the present invention is mounted on the magazine.

FIG. 4 shows a semiconductor device formed by the method of the present invention.

FIG. 5 is a view showing a normal lead frame.

FIG. 6 is a diagram showing a conventional curing process.

FIG. 7 is a view showing a semiconductor device formed by a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 2 Semiconductor chip 3 Wire 4 Encapsulation material 11 Die pad 12 Inner lead 13 Tie bar 14 Outer lead 15, 16 Side bar 17 Support bar 31 Magazine 32 Stopper plate 33 Semiconductor device 41a, 41b Pressure plate 42 Magazine 43 Handle 44 Pressure screw part 45 Holding frame 46 Semiconductor device

Claims (2)

(57) [Claims] 1. A semiconductor chip mounting step of mounting a semiconductor chip on a semiconductor chip mounting portion of a lead frame and making an electrical connection, and a mold for molding a package around the semiconductor chip with a resin. And a step of arranging the packages and packages located at both ends thereof.
By holding the surface with a pressure plate and applying pressure,
Place the upper and lower surfaces of the package on a pressure plate or
Pressurizing through a package, performing a heat treatment in a state where the package is constrained, and cooling while keeping the upper and lower surfaces pressed, and a separation molding step of separating and molding the external leads of the lead frame. A method for manufacturing a semiconductor device. 2. A box-shaped magazine body for accommodating a large number of molded semiconductor devices arranged in such a manner that their package surfaces are in contact with each other, and two sheets arranged opposite to each other inside the magazine body. A pressure plate made of a flat plate of the following, a pressure screw pressing the two pressure plates through an insertion hole provided in the magazine main body, and adjusting means for turning the pressure screw to adjust the pressed state. Heat treatment in a state where the semiconductor device is housed.
A container for a semiconductor device, characterized in that the container is configured to perform the operation .