JPS587060B2 - Makuno Pinhole Kenteihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting pinholes in a silicon oxide film and a resist film during the manufacturing process of a semiconductor device.

An object of the present invention is to prepare a pinhole test sample using a simple method and to easily identify pinholes in a membrane.

In semiconductor device production factories, the occurrence of pinholes in films is a fatal defect in semiconductor devices, resulting in a decrease in production yield.

In other words, the yield is reduced due to the leakage phenomenon of semiconductor devices.

Among film pinholes, resist film pinholes are the ones most likely to cause leakage, but the current situation is that accurate testing is not carried out at production plants.

The biggest reason for this is that the current pinhole verification method is extremely difficult.

Conventional methods for pinhole inspection of membranes include inspection using an electron microscope, and phosphorus, silica, glass (P, S,
There are methods such as testing using G).

However, the method using an electron microscope requires a large amount of investment to first install the equipment.

In addition, it is necessary to have a specialized operator on hand to prepare the sample and perform its observation and verification, which is difficult for anyone to do easily.

The method using P, S, G films also requires a large investment in equipment, and is not preferred from a safety standpoint because it uses poisonous gas (phosphine) to generate the P, S, G films.

This is a major problem at a time when companies' safety measures are currently in question.

However, the present invention eliminates all such drawbacks, is easier and cheaper than conventional methods, and is also superior in safety, allowing accurate pinhole inspection of membranes.

Here, the method for detecting pinholes in membranes according to the present invention will be explained in detail using figures.

After cleaning the surface of the silicon substrate 1 in Figure 1-(1), it is oxidized by thermal oxidation (1100°C x 40 minutes) to grow a silicon oxide film 2 of about 1000 Å as shown in Figure 1-(2). As shown in FIG. 1-(3), a resist 3 to be tested is applied onto the silicon oxide film 2 using a resist spinner.

The photoetching process is carried out with the resist 3 applied.

First, soft baking is performed, then the entire surface is exposed to light, followed by hard baking and then the etching process.

In this etching, the immersion time is longer than the time required to sufficiently remove the thickness of the oxide film grown on the silicon surface.

On the other hand, if the resist film 3 contains pinholes, pinholes will be generated in the oxide film 2 by this etching.

After the etching process is completed, the resist 3 is removed to leave only the oxide film 2, as shown in FIG. 1(4).

Thereafter, aluminum (Al) 4 is vacuum-deposited on the upper surface of the oxide film 2, as shown in FIG. 1-(5).

After vacuum deposition, sintering is performed at 500°C or higher.

This sintering is the process of causing a eutectic reaction between aluminum and silicon, which is a feature of the present invention.

Next, the final step of etching the entire surface of the aluminum 4 is carried out using phosphoric acid to obtain the state shown in FIG. 1-(6), and inspection is performed using an optical microscope.

FIG. 2 is a cross-sectional view when the verification resist 3 has a pinhole.

During sintering, a reaction between aluminum and silicon occurs through the oxide film, resulting in a eutectic state, but this material is not etched by the phosphoric acid solution and appears as reaction marks 5 on the oxide film.

Since this reaction mark 5 appears enlarged from the actual pinhole diameter, it can be easily identified with an optical microscope.

Although this embodiment has been explained using pinhole testing of a resist film, other insulating films such as silicon oxide films, silicon nitride films, etc. can also be tested without any change.

As explained above, the present invention uses existing semiconductor manufacturing equipment and can be easily performed by anyone, so it is the best method for testing mass-production factories.

In addition, the present invention broadly provides a method for pinhole testing of membranes that can be performed accurately, easily, and safely.

[Brief explanation of drawings]

FIG. 1 is a process sectional view of the pinhole verification method.

Claims (1)

[Claims] 1. In a semiconductor device using a silicon substrate, during pinhole inspection of films such as an insulating film formed on the silicon substrate during the manufacturing process of the semiconductor device and a resist film during the photo-etching process, silicon and aluminum (Al ) is a membrane pinhole assay method characterized by assaying using a eutectic reaction.