JPH11330158A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] To provide a package with improved connection reliability at a portion where a bump electrode and an electrode of a substrate are in contact. SOLUTION: A semiconductor chip 2 having solder bumps 3 formed on bonding pads BP is face-down connected to a main surface of a package substrate 1, and a gap between the semiconductor chip 2 and the package substrate 1 is filled with an underfill resin 5. In addition to reducing stress, the semiconductor chip 2 and the package substrate 1
By coating the respective surfaces of the solder bumps 3 with an insulating layer 6 having better adhesion than the underfill resin 5, the elements formed on the semiconductor chip 2 and the solder bumps 2 are covered.
This is a package that reliably protects the connection between the electrode and the upper electrode 4 from moisture and contaminants.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a manufacturing technique thereof, and more particularly, to a semiconductor device mounted on a wiring board via a bump electrode by flip-chip mounting, and an underfill in a gap between the semiconductor chip and the wiring board. The present invention relates to a technology effective when applied to a package to be filled with a resin.

[0002]

2. Description of the Related Art Conventionally, as a method of mounting a semiconductor chip on a wiring board such as a package board, a chip having bump electrodes formed on bonding pads is face-down connected to the wiring board, and the bump electrodes and the electrodes of the wiring board are connected to each other. Is widely used. The bump electrodes include, for example, solder bumps (JP-A-62-249429, JP-A-63-310139).
No. 3, pp. 157-64, and Au balls (Japanese Patent Laid-Open No. 6-333982).

[0003] Meanwhile, in a resin package in which the package substrate on which the chip is mounted is made of inexpensive synthetic resin to reduce the manufacturing cost, a ceramic package in which the thermal expansion coefficient of the package substrate is designed according to the chip is used. However, since the stress applied to the bump electrode due to the difference in the coefficient of thermal expansion between the chip and the substrate is large, the connection reliability between the chip and the package substrate becomes a problem.

As one of the countermeasures, the above-mentioned stress is relaxed by filling an underfill resin in a gap between the chip and the package substrate (for example, in April 1990, Electronic Information Communication). Academic Journal C11
Vol.J73-C-II No.9 p516-524). As the underfill resin, an epoxy resin or the like whose thermal expansion coefficient and Young's modulus are optimized so that the above-mentioned stress can be relaxed and absorbed is used.
The underfill resin also has a function as a protective film that protects elements formed on the main surface of the chip and the connection between the bump electrode and the electrode of the substrate from moisture and contaminants.

[0005]

However, in the case of a resin package in which an underfill resin is filled in a gap between a chip and a package substrate, an underfill for a surface protection film (passivation film) and a bump electrode formed on the main surface of the chip is provided. Because the adhesion of the fill resin is not always sufficiently considered, it may be difficult to protect the elements formed on the main surface of the chip and the connection between the bump electrode and the substrate electrode from moisture and contaminants. Occurs.

Therefore, it has been practiced to coat the main surface of the chip with a polyimide resin having good adhesion to the surface protective film. In this case, when forming the bonding pad, the polyimide resin is etched to form a lower layer. After exposing the surface protective film, the surface protective film must be further etched to expose the uppermost layer wiring, which complicates the wafer process.

An object of the present invention is to provide a semiconductor device in which a gap between a substrate and a chip mounted on the main surface thereof is filled with an underfill resin, the adhesion of the underfill resin to the main surface of the chip and the bump electrodes. It is to provide a technology for improving.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0009]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In a semiconductor device according to the present invention, a semiconductor chip having bump electrodes formed on bonding pads is face-down connected to a main surface of a wiring board, and a gap between the semiconductor chip and the wiring board is filled with an underfill resin. In the semiconductor device, a surface of each of the semiconductor chip, the wiring board, and the bump electrode is covered with an insulating layer having better adhesion than the underfill resin.

In the semiconductor device according to the present invention, the insulating layer can be mainly composed of a polyimide resin.

In the semiconductor device according to the present invention, the wiring substrate can be constituted mainly of a synthetic resin.

In the semiconductor device according to the present invention, the bump electrodes can be made of solder or Au.

A semiconductor device according to the present invention is a semiconductor device in which a semiconductor chip having bump electrodes formed on bonding pads is face-down connected to a main surface of a wiring board mainly composed of ceramic.
The surface of each of the wiring board and the bump electrode may be covered with the insulating layer.

The method of manufacturing a semiconductor device according to the present invention includes the following steps (a) to (d).

(A) a step of connecting a semiconductor chip having bump electrodes formed on bonding pads face-down to a main surface of a wiring board; and (b) a step of connecting the semiconductor chip to the gap between the semiconductor chip and the wiring board. Filling an insulating material having better adhesion to the surface, the main surface of the wiring board and the bump electrode than an underfill resin, and (c) filling the gap between the semiconductor chip and the wiring board with the insulating material. Removing a part thereof and forming an insulating layer made of the insulating material on each surface of the semiconductor chip, the wiring substrate, and the bump electrode; (d) forming a gap between the semiconductor chip and the wiring substrate; A step of filling the underfill resin.

[0017]

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

(First Embodiment) FIG. 1 is a sectional view showing a semiconductor device of the present embodiment. This semiconductor device is a resin package in which a semiconductor chip 2 is connected face down on a main surface of a package substrate 1 made of glass epoxy resin, BT resin or the like. The semiconductor chip 2 is mounted on the package substrate 1 by a flip-chip mounting method in which a solder bump (bump electrode) 3 connected to the bonding pad BP on the main surface is connected to the upper electrode 4 of the package substrate 1.

The gap between the semiconductor chip 2 and the package substrate 1 is filled with an underfill resin 5. The underfill resin 5 is provided to alleviate the stress applied to the solder bumps 3 due to the difference in thermal expansion coefficient between the semiconductor chip 2 and the package substrate 1. The underfill resin 5 can sufficiently reduce and absorb this stress. It is made of an epoxy resin with optimized thermal expansion coefficient and Young's modulus.

The underfill resin 5 also functions as a protective film for protecting the elements formed on the main surface of the semiconductor chip 2 and the connection between the solder bumps 3 and the upper electrode 4 from moisture and contaminants. Also serves as. However, since the underfill resin 5 is designed to relieve the stress applied to the solder bumps 3, the surface protection film formed on the main surface of the semiconductor chip 2 and the metal (the solder bumps 3, the upper electrode 4) ) Is not always good.

Therefore, in the present embodiment, the surface of each of the semiconductor chip 2, the package substrate 1 and the solder bumps 3 is made to have a surface protective film and an insulating layer which is superior in adhesion to metal as compared with the underfill resin 5. By coating with 6, it is protected from moisture and contaminants. This insulating layer 6
For example, it is made of a polyimide resin or an epoxy resin having improved adhesiveness.

On the lower surface of the package substrate 1, there is formed a lower electrode 7 which is electrically connected to the upper electrode 4 through a wiring (not shown) and a through hole. In addition, to these lower electrodes 7, solder bumps 8 constituting external connection terminals of the resin package are connected. The upper electrode 4 and the lower electrode 7 are formed by etching a rolled Cu foil (or an electrolytic Cu foil) bonded to both surfaces of the package substrate 1, and their surfaces are plated with Ni and Au. I have.

Next, an example of a method of manufacturing the resin package will be described. First, as shown in FIG. 2, a semiconductor chip 2 having solder bumps 3 formed on bonding pads BP is formed.
Is mounted on the package substrate 1 using a chip mounter (not shown), and the solder bumps 3 are reflowed and connected to the upper electrode 4.

Next, as shown in FIG.
After filling a gap between the semiconductor substrate 2 and the package substrate 1 with an insulating material 6a such as polyimide resin or epoxy resin having improved adhesiveness, a part of the insulating material 6a is packaged with the semiconductor chip 2 and the package as shown in FIG. The insulating layer 6 made of an insulating material 6a is formed on the surface of each of the semiconductor chip 2, the package substrate 1 and the solder bumps 3 by removing from the gap with the substrate 1. A part of the insulating material 6a is replaced with the semiconductor chip 2.
For example, air is blown into this gap to remove the gap from the gap between the package substrate 1 and the package board 1.

Thereafter, a gap between the semiconductor chip 2 and the package substrate 1 is filled with an underfill resin 5, and the underfill resin 5 and a resin constituting the insulating layer 6 are heated and cured. By connecting the solder bumps 8 to the lower electrodes 7, the resin package shown in FIG. 1 is completed.

According to the present embodiment configured as described above, the respective surfaces of the semiconductor chip 2, the package substrate 1, and the solder bumps 3 are covered with the insulating layer 6 having high adhesion to them. In addition, the elements formed on the semiconductor chip 2 and the connection between the solder bump 3 and the upper electrode 4 can be reliably protected from moisture and contaminants.

The semiconductor chip 2 and the package substrate 1
By filling the underfill resin 5 in the gap between
The stress applied to the solder bumps 3 due to the difference in thermal expansion coefficient between the semiconductor chip 2 and the package substrate 1 can be reduced.

Further, according to the present embodiment, a step of protecting the surface protection film of the semiconductor chip 2 with a polyimide resin prior to the step of forming the bonding pad BP is not required, thereby simplifying the wafer process. Can be.

(Embodiment 2) FIG. 5 is a sectional view showing a semiconductor device of the present embodiment. In the first embodiment, the package in which the package substrate is made of resin has been described. In the present embodiment, a ceramic package in which the package substrate 10 is made of a ceramic material such as mullite having a thermal expansion coefficient close to that of the semiconductor chip 2 is used. is there.

In this embodiment, since the stress applied to the solder bumps 3 due to the difference in the thermal expansion coefficient between the semiconductor chip 2 and the package substrate 10 is small, the underfill resin is formed in the gap between the semiconductor chip 2 and the package substrate 10. 5 are not filled, but in order to surely protect the elements formed on the semiconductor chip 2 and the connection between the solder bumps 3 and the upper electrode 4 from moisture and contaminants, the surfaces of the elements are the same as those of the above embodiment. It is covered with the insulating layer 6 used in 1.

According to the present embodiment configured as described above, the semiconductor bumps 2 mounted on the main surface of the package substrate 10 need not be sealed with a cap or the like.
It is possible to surely protect the connection between the electrode and the upper electrode 4 from moisture and contaminants, so that the manufacturing cost of the ceramic package can be reduced.

Although the invention made by the inventor has been specifically described based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention. It goes without saying that it is possible.

In the above embodiment, the package in which the bump electrodes are formed by solder bumps has been described. However, the present invention can be applied to a package in which the bump electrodes are formed by Au balls.

In the above-described embodiment, a case where the present invention is applied to a resin package or a ceramic package has been described. However, for example, a plurality of modules are mounted on a module substrate mounted on a thin and lightweight electronic device represented by a notebook personal computer or a portable terminal device. The present invention can also be applied to a case where a bare chip is flip-chip mounted.

[0035]

Advantageous effects obtained by typical ones of the inventions disclosed by the present application will be briefly described as follows.
It is as follows.

According to the present invention, the elements formed on the semiconductor chip and the connection between the bump electrodes and the electrodes can be reliably protected from moisture and contaminants. Since the stress applied to the bump electrode due to the difference in expansion coefficient can be reduced, a package with improved connection reliability at the portion where the bump electrode and the electrode are in contact can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view illustrating a method for manufacturing a semiconductor device according to an embodiment of the present invention;

FIG. 4 is a cross-sectional view illustrating the method of manufacturing the semiconductor device according to one embodiment of the present invention;

FIG. 5 is a sectional view showing a semiconductor device according to another embodiment of the present invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 package substrate 2 semiconductor chip 3 solder bump (bump electrode) 4 upper electrode 5 underfill resin 6 insulating layer 6 a insulating material 7 lower electrode 8 solder bump 10 package substrate BP bonding pad

Claims (6)

[Claims] 1. A semiconductor device wherein a semiconductor chip having bump electrodes formed on bonding pads is face-down connected to a main surface of a wiring board, and a gap between the semiconductor chip and the wiring board is filled with an underfill resin. A semiconductor device, wherein the respective surfaces of the semiconductor chip, the wiring substrate and the bump electrode are covered with an insulating layer having better adhesion than the underfill resin. 2. The semiconductor device according to claim 1, wherein the insulating layer is mainly composed of a polyimide resin. 3. The semiconductor device according to claim 1, wherein the wiring substrate is mainly composed of a synthetic resin. 4. The semiconductor device according to claim 1, wherein the bump electrode is made of solder or Au. 5. A semiconductor device in which a semiconductor chip having bump electrodes formed on bonding pads is face-down connected to a main surface of a wiring board mainly composed of ceramic, wherein the semiconductor chip, the wiring board, and the A semiconductor device, wherein each surface of a bump electrode is covered with the insulating layer according to claim 1. 6. A method of manufacturing a semiconductor device, comprising the following steps (a) to (d): (a) placing a semiconductor chip having bump electrodes formed on bonding pads on a main surface of a wiring board; (B) an insulating material having better adhesion between the main surface of the semiconductor chip, the main surface of the wiring substrate, and the bump electrode than an underfill resin in a gap between the semiconductor chip and the wiring substrate; (C) removing a part of the insulating material filled in the gap between the semiconductor chip and the wiring board, and forming the insulating material on the respective surfaces of the semiconductor chip, the wiring board, and the bump electrodes. (D) filling the gap between the semiconductor chip and the wiring board with an underfill resin.