JPH0738027A - Resin-sealed semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a highly reliable resin-encapsulated semiconductor device capable of surely covering the entire surface of a semiconductor chip with a junction coating resin during assembly. [Structure] In a resin-sealed semiconductor device in which a semiconductor chip is mounted on a metal substrate and is wholly sealed with a molding resin, a semiconductor chip 4 is previously immersed on the upper surface of a die pad 2 of a lead frame 1 which is a metal substrate. After forming the recess 2a having a depth, the semiconductor chip is mounted in the recess, and the surface of the semiconductor chip is coated by filling the junction coating resin with fluidity so as to fill the recess. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-encapsulated semiconductor device in which a semiconductor chip is mounted on a metal substrate and the whole is encapsulated with a molding resin.

[0002]

2. Description of the Related Art Recently, in order to improve the reliability of the above-mentioned resin-encapsulated semiconductor device, in particular, the moisture resistance of a semiconductor chip, it has recently been mounted on a metal substrate before molding with a molding resin. It has been practiced to cover the surface of the semiconductor chip with a coating agent having high moisture resistance, and as the coating agent, for example, a polyimide resin junction coating resin is known. In this junction coating resin, a surface of the chip is coated by potting it onto a semiconductor chip with a dispenser in a state where a fluid is added by adding a solvent. The resin is dried and cured after coating.

[0003]

By the way, when the surface of the semiconductor chip is covered with the junction coating resin as described above, it becomes extremely difficult to completely coat the surface of the chip unless the viscosity of the resin is appropriate. . That is, if the viscosity of the junction coating resin is too low, a part of the resin flows out around the semiconductor chip during potting, and the resin does not remain on the outer peripheral edge of the chip, especially at the corners. On the contrary, when the viscosity is too high, the fluidity is insufficient and the resin is solidified in the central surface area of the chip, and the peripheral area of the chip is not covered with the resin as in the above.

Moreover, even if a highly reliable junction coating resin is used as the coating agent, if the surface of the semiconductor chip is not completely covered by the difference in the viscosity of the resin, it is used in a high humidity atmosphere. At this time, the moisture that has entered the package from the outside reaches the semiconductor chip and deteriorates the characteristics, which lowers the reliability of the semiconductor product.

The present invention has been made in view of the above points, and an object thereof is to solve the above problems and improve a metal substrate for mounting a semiconductor chip so that the entire surface of the semiconductor chip is coated with a junction coating resin. It is an object of the present invention to provide a highly reliable resin-sealed semiconductor device that can be surely covered with.

[0006]

To achieve the above object, in a semiconductor device of the present invention, a recess is formed on the upper surface of a metal substrate, and a semiconductor chip is mounted in the recess, and The top surface of the chip shall be covered with a fluid junction coating resin in the recess.

Here, the depth of the recess in the above construction is
It should be selected to be larger than the thickness of the semiconductor chip. The semiconductor device can be assembled by using a lead frame and forming a recess in the die pad.

[0008]

[Function] As described above, by mounting the semiconductor chip in the recess formed in the metal substrate in advance and potting the junction coating resin which has fluidity so as to fill the recess, the dispersion of the viscosity can be prevented. Regardless of this, the entire surface of the semiconductor chip is completely covered with the resin, and the moisture resistance is improved. Therefore, the viscosity condition for the junction coating resin is relaxed, and the process control becomes easier.

[0009]

Embodiments of the present invention will be described below with reference to FIGS. In the figure, 1 is a lead frame, 2 is a die pad (metal substrate) of the lead frame 1, 3 is an external lead, 4 is a semiconductor chip, 5 is a bonding wire connecting between the semiconductor chip 4 and the external lead 3, and 6 is It is a package molded with a molding resin. Here, the die pad 2 of the lead frame 1 is pre-formed with a recess 2a having a depth into which the semiconductor chip 4 is immersed. The semiconductor chip 4 is mounted in this recess and then the recess 2a is further mounted. A junction coating resin 7 is filled so as to fill the place 8 and completely cover the surface of the semiconductor chip 4.

A solvent is added to the junction coating resin 7 to impart appropriate fluidity thereto, and the semiconductor chip 4 is mounted in the recess 2a of the die pad 2.
Further, in the assembled state where the wire 5 is bonded, the surface of the semiconductor chip 4 is coated by potting from above so as to fill the recess 2a. Then, after the junction coating resin 7 is dried and cured, the resin package 6 is molded in the peripheral region of the semiconductor chip 4 by the transfer molding method to complete the semiconductor device.

[0011]

As described above, according to the present invention, a recess is formed in a metal substrate, a semiconductor chip is mounted on the recess, and then a junction coating resin is filled so as to fill the recess. Therefore, the surface of the semiconductor chip can be surely covered with the junction coating resin without being influenced by the viscosity of the resin, thereby providing a semiconductor device having high reliability in terms of moisture resistance and the like. In addition, there are advantages in terms of management, such as not having to strictly control the viscosity of the junction coating resin.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along line XX in FIG.

[Explanation of symbols]

 1 lead frame 2 die pad (metal substrate) 2a recess 4 semiconductor chip 6 resin package 7 junction coating resin

Claims (3)

[Claims] 1. A semiconductor chip is mounted on a metal substrate,
In a resin-encapsulated semiconductor device in which the whole is sealed with a mold resin, a recess is formed on the upper surface of a metal substrate, and a semiconductor chip is mounted in the recess, and the upper surface of the semiconductor chip is covered to form a recess. A resin-encapsulated semiconductor device, which is filled with a junction coating resin having fluidity. 2. The semiconductor device according to claim 1, wherein the depth of the recess is larger than the thickness of the semiconductor chip. 3. The resin-encapsulated semiconductor device according to claim 1, wherein the metal substrate is a die pad of a lead frame.