JPH07122609A - Method for analyzing detective bump - Google Patents

Abstract

PURPOSE:To detect insufficient connection at a bump positively while protecting the bump against damage when it is exfoliated from a substrate. CONSTITUTION:In a semiconductor device where a semiconductor chip 1 is connected with a substrate 3 through a bump 2, a resin 8 is cured around the bump. The substrate is then heated to exfoliate the semiconductor chip therefrom and the surface state of the bump is observed. An insufficiently connected bump is then specified based on the adhesion of resin or the abnormal surface state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bump failure analysis method, and more particularly to a method for inspecting the connection status of a semiconductor device connected by bumps.

[0002]

2. Description of the Related Art In recent years, as a semiconductor mounting technique, a technique of mounting a plurality of chips in one package has been used.

As shown in FIG. 3, this technique mounts a plurality of chips 1 on a wired microchip substrate (MCS) 3 via bumps 2, and mounts the microchip substrate on a microchip module ( It is housed in a package called MCM) 4 and has a structure in which the external lead 5 provided on the microchip module and the terminal of the microchip substrate are connected by wires 7 or the like.

When performing a failure analysis of such a semiconductor device, the chip must be separated from the microchip substrate. As a method for this purpose, conventionally, a semiconductor device was placed on a heat block, the package was opened, and the chip was thermally separated from the microchip substrate. Alternatively, peeling is performed using a chemical solution such as nitric acid or sulfuric acid.

[0005]

In the defect analysis by the conventional method, the opening of the package (peeling of the cap) can be performed without any problem, but the bumps are damaged by heat or a chemical solution when the chip and the microchip substrate are peeled. Therefore, it was difficult to detect defects in the bumps.

An object of the present invention is to prevent the bumps from being damaged at the time of peeling the bumps from the substrate and to ensure the detection of the connection failure at the bumps.

[0007]

[Means for Solving the Problems] To solve the above problems, a semiconductor device in which a semiconductor chip 1 is connected to a substrate 3 via bumps 2 is solidified around the bumps with a resin 8 and then the bumps are solidified. Characterized in that the substrate is heated to peel off the semiconductor chip from the substrate, and then the surface condition of the bumps is observed to identify bumps with poor connection based on the presence or absence of resin adhesion and abnormal surface condition. Bump defect analysis method.

[0008]

In the present invention, since a low-viscosity thermosetting resin is poured into the cavity around the bump to cure the resin, the chip and the substrate are thermally peeled off. Without damage, it is possible to observe whether the resin is attached to the bump surface of the defective connection portion or whether the peeled surface is abnormal. Therefore, it is possible to detect the connection failure at the bump.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view for explaining an embodiment of the present invention. In the figure, 1 is a chip, 2 is a solder bump, 3 is a microchip substrate (MCS), 4 is a microchip module (MCM), 5 is a lead, 6 is a cap made of metal or the like, 7 is a bonding wire, 8 Is the injected resin.

An example of a specific failure analysis procedure for the semiconductor device shown in FIG. 3 is shown below. (1) A hole is made in the cap 6, and a low-viscosity thermosetting resin 8, such as araldite, is injected into the space formed by the cap 6 and the microchip module 4. The amount of resin injected may be such that the cavity around the bump is filled. (2) The semiconductor device is heated to cure the resin. (3) Place the semiconductor device on the heated heat block,
Peel the chip from the substrate. (4) Observe the bump surface with a metallographic microscope.

At this time, if the resin adheres to a certain bump, it is verified that this bump has an open defect [see FIG. 2 (A)]. It can also be seen that when a foreign substance is present on the surface of a bump or the bump is covered with a thick oxide film, this bump has an open defect [Fig.
(B)].

Although heat is used to cure the resin in the embodiments, in a semiconductor device having a structure in which the cap can be peeled off separately from the chip, the resin can be irradiated with light to cure the resin.

[0013]

According to the present invention, the bump and the substrate can be separated from each other without damaging the bump. As a result, it became possible to reliably detect defective connections at bumps, which contributed to improved device reliability.

[Brief description of drawings]

FIG. 1 is a sectional view illustrating an embodiment of the present invention.

FIG. 2 is a sectional view of a defective bump in the example.

FIG. 3 is a cross-sectional view of a semiconductor device connected by bumps.

[Explanation of symbols]

 1 chip 2 bump 3 microchip substrate (MCS) 4 microchip module (MCM) 5 lead 6 cap 7 bonding wire 8 resin 9 foreign material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshitaka Niwa, Yoshitaka Niwa 1844-2, Kozoji-cho, Kasugai-shi, Aichi Fujitsu Vielle SII Co., Ltd. (72) Inventor Tomoko Katagiri 2-1844-2, Kozoji-cho, Kasugai-shi, Aichi Within Fujitsu VIS Ltd.

Claims (1)

[Claims] 1. A semiconductor device in which a semiconductor chip (1) is connected to a substrate (3) through a bump (2), the periphery of the bump is solidified with a resin (8), and then the substrate is solidified. Of the bump, characterized in that the semiconductor chip is peeled off from the substrate by heating, and then the surface condition of the bump is observed to identify the bump with poor connection based on the presence or absence of resin adhesion and the abnormal surface condition. Failure analysis method.