JPS61102050A - Semiconductor memory storage - Google Patents

Abstract

PURPOSE:To estimate an acceptable protective film or a defective one previously by forming another wiring layer onto the protective film and measuring characteristics between two of a wiring layer and another wiring layer when a diffusion layer is formed to the surface layer section of a semiconductor substrate, the whole surface containing the diffusion layer is coated with an oxide film, an opening is bored, the wiring layer being in contact with the diffusion layer is applied, the wiring layer is coated with the protective film and a memory storage is shaped. CONSTITUTION:A diffusion layer 2 is formed to the surface layer section of a semiconductor substrate 1, an oxide film 3 is applied onto the whole surface containing the layer 2, an opening is bored made to correspond to the diffusion layer 2, and an Al wiring layer 4 is shaped onto the whole surface while being brought into contact with the diffusion layer 2. The whole surface is coated with a passivation film 5, an opening is bored to a bonding pad section B, a bonding wire is connected to the wiring layer 4 and a memory storage is shaped, but another Al wiring 7 is formed previously only onto a memory section C at that time. According to such constitution, an acceptable passivation film 5 or a defective one and the deterioration of the film 5, which will be shaped afterwards, can also be decided when electrical characteristics are measured by using the wirings 7 and 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor memory device, and more particularly to improving the moisture resistance of a memory portion of a semiconductor memory device using a plastic package.

[Conventional technology]

A schematic configuration of this type of semiconductor memory device according to a conventional example is shown in FIG. 3. In other words, in FIG. A diffusion layer formed on the surface of the substrate l; 3 an oxide film formed on the surface of the semiconductor substrate l to serve as an insulating film; 4 an aluminum wiring layer connected to the diffusion M2; 5 these surfaces. The passivation film 6 is a bonding wire connected to the layer 4, and the bonding portion is normally connected to the passivation layer 4. It has a structure lacking the i5 coating.

Therefore, in general, development of semiconductor integrated circuits is progressing to meet the demands of electronic devices becoming smaller, lighter in weight, and lower in price. In the early stages of mass production, ceramic packages were used, as they had relatively loose restrictions on chip size and were easy to ensure reliability, but as product prices fell, they gradually shifted to lower-priced plastic packages. I've been doing it.

FIG. 4 shows the structure of a plastic package for the semiconductor memory device. That is, in FIG. 4, reference numeral 8 is a metal frame on which the semiconductor memory chip A is mounted, and 9 is a lead bin for external connection, to which the bonding wire 6 is connected. Except for the take-out legs, it is sealed and packaged with plastic IO.

[Problem that the invention seeks to solve]

Conventional semiconductor memory devices using plastic packages are configured as described above, and the biggest problem with plastic packaging is moisture resistance due to the non-airtightness of plastic packages. .

That is, in the semiconductor memory chip A, ensuring reliability depends on the passivation film 5 covering the chip surface. 11, the arrow 12 from the sealing part of the plastic 10
Intrusion of moisture from the external atmosphere as shown in FIG. 1 may corrode the aluminum wiring layer 4 within the chip through this faulty portion 11, resulting in connection failure.

Even if the semiconductor memory chip A whose aluminum wiring layer N4 is corroded is operated, it will not become defective until the wiring layer 4 is completely disconnected.
For devices with low leakage current, there are signs of an increase in leakage current, but an increase in leakage current does not immediately lead to corrosion, and it is difficult to detect even the signs of corrosion in normal devices. The only way to find out is by opening the package, and even when there are no abnormalities in appearance or electrical characteristics, corrosion progresses gradually, so there is a possibility that the equipment may suddenly malfunction. As described above, in semiconductor memory chips, #decreased humidity and corrosion of the aluminum wiring layer are undesirable from the viewpoint of reliability of the product itself, and even if there are defects in the passivation film at the time of manufacture, it will not be possible at the initial testing stage. It could only be judged as a non-defective product, which would cause future problems such as corrosion of aluminum and malfunction of the equipment.

This invention has been made to solve these conventional problems, and aims to provide a semiconductor memory device that can detect products that cause corrosion of aluminum wiring layers at an early testing stage. It is something.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides an aluminum wiring layer under the aluminum wiring layer, as well as the aluminum wiring layer under the aluminum wiring layer.
An aluminum wiring coating layer is also formed on the aluminum film.
The electrical characteristics can be measured in both wiring rooms made up of these two layers.

[For production]

Therefore, in the semiconductor memory *a according to the present invention, 2N! By performing an electrical characteristic test between the two wiring layers, it is possible to determine whether the passivation film interposed between the two wiring layers is good or not, and whether there are any defects.

〔Example〕

Hereinafter, one embodiment of a semiconductor memory device according to the present invention will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view of the main parts of this embodiment of the apparatus in correspondence with the conventional apparatus shown in FIG. 3, and FIG. 2 is an explanatory plan view showing the overall structure of the same apparatus.

In the embodiments shown in FIGS. 1 and 2, the same reference numerals as in the conventional example shown in FIG. This aluminum wiring coating 57 can be easily formed by, for example, a conventionally known two-layer wiring method.

In this case, the coverage range of the aluminum wiring coating layer 7 may be the entire area of the memory section C, as shown in FIG. It is effective for detecting abnormalities or defects in the area, and there is no problem in covering the entire area except for the bonding pad portion as necessary.

Therefore, in the case of this embodiment configuration, the passivation 1
Obstacles such as cracks and pinholes on 15!5 11
etc., between the aluminum wiring layer 4 selectively formed on the oxidized H3 and the aluminum wiring covering layer 7 formed entirely on the same wiring layer 4 with a passivation film 5 interposed therebetween. As a result, it is possible to determine whether the product is defective by testing the electrical characteristics between these two membranes 4.7 at an early stage after manufacturing the device. This makes it possible to eliminate defective products before conducting moisture resistance evaluation tests such as high-temperature, high-humidity tests, and pressure-kunker tests.

〔Effect of the invention〕

As described in detail above, according to the present invention, in the configuration of a semiconductor memory device, an aluminum wiring covering layer is formed not only on the aluminum wiring layer under the passivation film but also on the passivation film. Since it is possible to measure the electrical characteristics of the device configuration between the two layers, it is possible to detect defects in the passivation film.
Memory chips with defects, in other words memory chips that may cause corrosion of the aluminum wiring layer in the future, can be eliminated in the initial test. On the one hand, the formation of this material improves the moisture resistance of the device, and on the other hand, due to the buffer effect generated from the soil that covers the entire surface, it is possible to sufficiently increase the pressure resistance and protection properties during plastic sealing, and it is also simple in construction. It has the advantage of being easy to implement.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of a semiconductor memory device according to an embodiment of the present invention, FIG. 2 is an explanatory plan view showing the overall structure of the same device, and FIG. 2 is a cross-sectional view. A: Semiconductor memory chip, B: Ponding butt portion, C: Memory portion, 1: Silicon semiconductor substrate, 2: Diffusion layer, 3: Oxidation membrane, 4
... Aluminum wiring layer, 5 ... Passivation film, 6 ... Bonding wire, 7 ... Aluminum wiring arrangement a coating layer, gate electrode, 8 ... Metal frame, 9 ... ...Lead pin, 10...Sealing plastic. Agent Masuo Oiwa Figure 1 1; 4 fathoms 4 curtains 5: 4 fathoms Figure 2 Figure 3 Figure 4 Procedural amendment (voluntary) March 19, 1985 2 , Title of the invention: Semiconductor memory device 3, Person making the amendment (1) Brief description of drawings in the specification - 4

Claims (1)

[Claims] 1. A semiconductor memory device having a configuration in which a passivation film is formed on an aluminum wiring layer except for a bonding pad portion, and an aluminum wiring coating layer is formed to cover at least the passivation film.