KR100800695B1 - Method for detecting damage of a semiconductor wafer - Google Patents

Abstract

A method for detecting damage of a wafer using discoloration is provided to easily detect damage of a wafer by inspection equipment by causing discoloration of a nitride film caused by a nitride step between a region where a wafer is damaged by a CMP process and a normal region. Nitride used as an end point of a CMP process can be removed by a wet etching process. Nitride(16) is deposited on a surface of a wafer having undergone a CMP process. An image of the nitride deposition surface of the wafer is acquired by inspection equipment using visual light as a light source. Damage by discoloration is detected from the image.

Description

METHOD FOR DETECTING DAMAGE OF A SEMICONDUCTOR WAFER}

1A and 1B are cross-sectional views illustrating a damage process on a wafer in a conventional CMP process.

2 is an image obtained by using a wafer inspection apparatus of the conventional wafer damage,

3A to 3E are cross-sectional views for explaining a wafer damage detection method using a discolor according to the present invention;

Figure 4 is an image of the wafer damage detected by the wafer damage detection method using a discolor according to the present invention.

<Description of Symbols for Main Parts of Drawings>

11 silicon substrate 12 pad oxide

13: nitride 14: cap fill material

15 device isolation layer 16 nitride

The present invention relates to a damage detection method of a wafer using a discolor, and more particularly, to a discoloration of a nitride film due to a step of nitride between a region where a damage occurs due to CMP and a normal region in a wafer ( The present invention relates to a wafer damage detection method using a discolor that makes it possible to easily detect damage to a wafer by inspection equipment by causing discolor).

Recently, in order to planarize the widened surface of the wafer as the wafer is large-sized, a chemical-mechanical polishing (CMP) process is performed by mixing chemical removal and mechanical removal into one processing method. This is widely used.

Such a CMP process may cause damage when the wafer is excessively polished. The damage generation of the wafer will be described with reference to the accompanying drawings.

1A and 1B are cross-sectional views illustrating a process in which damage is generated on a wafer in a conventional CMP process.

As shown in FIG. 1A, a pad oxide 2 and a nitride 3 are formed on the semiconductor substrate 1 by vapor deposition, and then a trench having a predetermined depth is formed, and a trench is formed inside the trench. The gap-fill material 4 is embedded.

Then, by polishing the unnecessary cap-fill material 4 by CMP using the nitride 3 as an end point, the device isolation film 5 having the STI structure is formed as shown in FIG. At this time, local damage D occurs in an iso pattern having a low pattern density of the nitride 3.

However, even if local damage (D) occurs due to excessive CMP on such a wafer, as shown in FIG. 2, damage from an image acquired by an inspection apparatus using visual light as a light source is shown. It could not be identified between the region (D) and the normal region, and the cause could be identified only by analyzing the structure of the wafer after the production was completed.

As a result, wafer damage due to excessive CMP of a particular CMP equipment cannot be detected on the line, and the degree of damage cannot be predicted, which leads to a decrease in reliability and a lower yield for the customer. In particular, wafer damage due to excessive CMP has a serious adverse effect on semiconductor device characteristics.

The present invention is to solve the above-mentioned conventional problems, the present invention is to discolor the discoloration of the nitride film (nitride film) due to the step of the nitride between the normal region and the damage region due to the CMP in the wafer It is easy to detect the damage of the wafer with the inspection equipment, thereby providing a damage detection method of the wafer using a descal that improves the yield and reliability of the semiconductor device by early detection of the wafer having damage and the problem equipment It is.

In order to achieve the above object, the present invention provides a method for detecting damage to a wafer after a CMP process, comprising: depositing nitride on a wafer after the CMP process, and visualizing a nitride deposition surface of the wafer. And acquiring an image with an inspection apparatus using the light as a light source, and detecting damage caused by the descalar from the image.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

3A to 3E are cross-sectional views for explaining a wafer damage detection method using a discolor according to the present invention. As shown, the damage detection method of the wafer using the descaling according to the present invention comprises the steps of depositing nitride on the wafer, acquiring an image of the wafer with the inspection equipment, and detecting the damage caused by the descalar from the image Steps.

Meanwhile, prior to the deposition of nitride on the wafer, the nitride used as an end point of the CMP process may be removed by wet etching.

The removal of nitride, which is used as an end point of the CMP process on the wafer, by etching is performed by depositing pad oxide 12 and nitride 13 on the semiconductor substrate 11 in FIG. 3A. Formed sequentially by forming a trench having a predetermined depth, embedding a gap-fill material 14 inside the trench, and then ending the nitride 13, as shown in FIG. 3B. As an end point, an unnecessary cap-fill material 14 is polished by CMP to form the device isolation film 15 having an STI structure, and then the nitride 13 is subjected to moist wet etching. Removal as in 3c ensures that there is a step by damage (D) upon deposition of nitride on the wafer, which is a subsequent step.

In the deposition of nitride on the wafer, as shown in FIG. 3D, the nitride 16 is deposited on the surface after the CMP process, at which time the nitride 16 is damaged by CMP damage. It forms a step by thickness.

On the other hand, when the nitride 16 is deposited on the wafer, the thickness is 200 to 400 kPa, preferably 300 kPa, and the nitride 16 having a thickness within this range can cause an effective descaling of the damage.

Acquiring the wafer with the inspection equipment may acquire an image using an inspection equipment using the nitride 16 deposited surface of the wafer as a visual light source.

Detecting damage by the descaling from the image generates a step due to the damage (D) formed on the wafer surface of the nitride (16) deposited on the wafer, and obtained from the inspection equipment by the step of the nitride (16) Discoloring is caused in one image to facilitate the detection of damage (D).

On the other hand, the nitride 16 deposited by the step of depositing the nitride after the step of detecting the damage (D) can be removed, as shown in Figure 3e by a wet wet etching (moat wet etching). .

Operation of the wafer damage detection method using the descaler having such a structure is performed as follows.

After the nitride 13 used as the end point of the CMP process is removed by mortise etching, damage D is generated by depositing the nitride 16 on the surface thereof, as shown in FIG. 3D. It causes discolor due to the step of the nitride 16 between the place and the normal region, so that the damage D of the wafer which is not detected by the inspection equipment can be easily detected.

That is, as shown in FIG. 4, it can be seen that the discolor is caused between the damage D and the normal region N in the image acquired by the inspection apparatus, thereby initializing the wafer and the problem equipment having the damage. By detecting the, the yield and reliability of the semiconductor element are improved.

As described above, the method for detecting damage of a wafer using a discolor according to the present invention is a discolor of a nitride film due to a step of nitride between a region where a damage occurs due to CMP and a normal region in the wafer. It is possible to easily detect the damage of the wafer with the inspection equipment by causing the), thereby having an effect of improving the yield and reliability of the semiconductor device by early detection of the wafer and the problem equipment having the damage.

What has been described above is just one embodiment for carrying out the wafer damage detection method using the discolor according to the present invention, the present invention is not limited to the above-described embodiment, as claimed in the following claims As described above, any person having ordinary knowledge in the field of the present invention without departing from the gist of the present invention will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (4)

In the method for detecting damage to the wafer after the CMP process, Depositing nitride on the wafer after the CMP process; Acquiring an image with an inspection device using the nitride deposited surface of the wafer as a visual light source; Detecting damage by the descalar from the image Damage detection method of the wafer using a discolor comprising a. The method of claim 1, Prior to depositing the nitride by performing wet etching to remove the nitride used as an endpoint of the CMP process on the wafer. Damage detection method of the wafer using a discolor. The method of claim 1, Deposition of the nitride, Deposited to a thickness of 200 to 400 microns Damage detection method of the wafer using a discolor. The method of claim 1, Performing a step of removing the deposited nitride by wet etching after the step of detecting the damage by depositing the nitride. Damage detection method of the wafer using a discolor.

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