TWI565940B - Evaluation method, evaluation device and utilization of organic matter contamination on the surface of a semiconductor substrate - Google Patents

Description

Method for evaluating organic matter contamination on a surface of a semiconductor substrate, evaluation device, and utilization thereof

The present invention relates to a method for evaluating organic matter contamination on a surface of a semiconductor substrate, and more particularly to an evaluation method for utilizing photoluminescence to evaluate organic matter contamination on a surface of a semiconductor substrate and utilization thereof.

Examples of the contaminant on the surface of the contaminated semiconductor substrate include organic substances derived from a manufacturing apparatus or a storage container of the semiconductor substrate.

The contamination of the organic material on the surface of the semiconductor substrate causes a phenomenon in which the gate insulating film causes occurrence of sporadic failure of the aging dielectric breakdown phenomenon and deterioration of the module performance such as deterioration of the oxide film withstand voltage. Therefore, in order to stably supply a semiconductor substrate capable of manufacturing a high-quality component, it is required to evaluate the organic contamination on the surface of the semiconductor substrate and discriminate the defective substrate (contaminated semiconductor substrate) to be excluded from the shipped product substrate, and judge whether or not the product is in the product. Before the substrate is shipped, it is necessary to remove the organic matter (removal of the necessity), and to perform process management for eliminating the cause of the contamination. Therefore, various methods for evaluating the contamination of organic substances on the surface of a semiconductor substrate have been proposed (for example, the methods described in Patent Documents 1 to 3, etc.).

[Prior patent documents]

[Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2002-368050

[Patent Document 2] Japanese Patent Laid-Open No. Hei 8-220071

[Patent Document 3] Japanese Patent Laid-Open No. Hei 6-283582

However, the above-described conventional evaluation method has problems in measurement time, measurement sensitivity, low resolution, and destruction inspection.

Accordingly, it is an object of the present invention to provide a new evaluation method for organic contamination on the surface of a semiconductor substrate.

The inventors of the present invention have repeatedly focused on the results of the review in order to achieve the object, so that the conventional method for analyzing defects or metal contamination in the semiconductor substrate is not used for analyzing the surface attachment of the semiconductor substrate. A contaminated photoluminescence method that evaluates new knowledge of organic contamination on the surface of semiconductor substrates. In addition, the photoluminescence method has high measurement sensitivity and high resolution on the measurement principle, and is an excellent method for measuring non-destructive inspections that are time-consuming.

More specifically, the surface of the semiconductor substrate is likely to be positively charged due to the influence of the natural oxide film, and the negatively charged organic substance is liable to adhere. Further, when a negatively charged organic substance adheres, it can be carried on the p-type tendency accumulation side due to a negative charge, and on the n-type tendency reversal side, since the surface level which is not filled with electrons increases, the SRH at the surface level is Recombination becomes easy to happen. As a result, the photoluminescence (hereinafter also referred to as "PL") signal (PL intensity) is weakened at the portion where the organic substance on the surface of the semiconductor substrate adheres. By utilizing this, based on the information about the PL intensity (PL intensity information), the organic matter on the surface of the semiconductor substrate can be evaluated. Pollution, this is the new discoverer of the results of the inventors' focused review. Therefore, by comparing the PL intensity information of the reference substrate having no organic contamination (or less organic contamination), it is possible to evaluate the presence or degree of organic contamination on the surface of the semiconductor substrate to be evaluated. Further, based on the in-plane distribution information of the PL intensity obtained on the surface of the semiconductor substrate to be evaluated, it is also possible to evaluate the in-plane distribution of the organic matter contamination on the surface of the semiconductor substrate to be evaluated (what part of the organic matter is attached to the surface, and many organic substances are attached to the surface). Which part of it, etc.).

The present invention has been completed based on the above knowledge.

That is, one aspect of the present invention is a method for evaluating organic matter contamination on a surface of a semiconductor substrate, comprising: obtaining photoluminescence intensity information on a surface of the semiconductor substrate to be evaluated; and evaluating the evaluation based on the obtained photoluminescence intensity information An evaluation item for group selection consisting of the presence or absence, degree, and in-plane distribution of organic matter contamination on the surface of the target semiconductor substrate.

In one aspect, the photoluminescence intensity information includes in-plane distribution information of the photoluminescence intensity of the surface of the semiconductor substrate to be evaluated.

In one form, at least an assessment of the in-plane distribution of organic contamination is performed.

In this regard, in order to estimate the cause of organic contamination on the surface of the semiconductor substrate contaminated with organic matter, and to perform process management in which the cause is excluded, it is preferable to obtain in-plane distribution information of organic matter contamination on the surface of the semiconductor substrate. This is because the manufacturing device or the storage container of the semiconductor substrate is located in the vicinity of (or in contact with) the region where the organic contamination is caused by the in-plane distribution information, and the possibility of occurrence of organic contamination on the surface of the semiconductor substrate is high. . However, the evaluation methods described in Patent Documents 2 and 3 above are in the middle. On the surface of the conductor substrate, in-plane distribution information of organic contamination is not obtained. On the other hand, the in-plane distribution information of the organic substance contamination on the surface of the semiconductor substrate can be obtained by, for example, an evaluation method based on the contact angle measurement of the surface of the semiconductor substrate or an evaluation method based on the surface photovoltage described in Patent Document 1. However, these evaluation methods are based on measurement sensitivity and require further improvement. In contrast, according to the above evaluation method, the in-plane distribution information of the organic matter contamination on the surface of the semiconductor substrate can be evaluated with high sensitivity. Then, based on the evaluation results obtained in this way, the cause of the organic contamination on the surface can be estimated.

The semiconductor substrate may be either a p-type or an n-type, and may be a p-type semiconductor substrate in one form. Since the PL intensity difference caused by the difference in PL intensity or the difference in adhesion between the adhered portion and the unattached portion is larger than the n-type, a higher contrast in-plane distribution information can be obtained on the p-type semiconductor substrate. .

Further, as described above, since the organic matter contamination on the surface of the semiconductor substrate can be evaluated, according to another aspect of the present invention, the presence or absence of the occurrence of organic contamination of the device in which the semiconductor substrate is disposed during production or storage can be evaluated. degree.

That is, another aspect of the present invention is an evaluation method of a device, which is an evaluation method of a device in which a semiconductor substrate is disposed during manufacture or storage, comprising: obtaining photoluminescence intensity information on a surface of a semiconductor substrate disposed on the device And evaluating an evaluation item of the group selection consisting of the presence or absence of organic contamination on the surface of the semiconductor substrate of the device based on the obtained photoluminescence intensity information.

In one form, according to the in-plane distribution of the photoluminescence intensity It is speculated that the cause of organic contamination on the surface of the semiconductor substrate of the device can be inferred.

In one form, the device is a containment vessel for a semiconductor substrate.

According to still another aspect of the invention, a method of manufacturing a semiconductor substrate includes: preparing a step of preparing a semiconductor substrate composed of a plurality of semiconductor substrates; and extracting a step of extracting at least one semiconductor substrate from the batch; a step of evaluating the extracted semiconductor substrate; and at least one semiconductor substrate selected from the group consisting of the semiconductor substrate on which the good product is evaluated and the other semiconductor substrate in the same batch of the semiconductor substrate is selected as the product substrate After the cleaning process is performed on at least one semiconductor substrate selected from the group consisting of the semiconductor substrate on which the defective product is judged and the other semiconductor substrate in the same batch of the semiconductor substrate, the organic matter contamination on the surface is reduced. The product substrate is shipped; the extracted semiconductor substrate is evaluated by the above-described evaluation method of organic matter contamination on the surface of the semiconductor substrate.

Another aspect of the present invention provides an apparatus for evaluating contamination of an organic substance on a surface of a semiconductor substrate, comprising: a measuring unit that obtains photoluminescence intensity information on a surface of the semiconductor substrate to be evaluated; and an evaluation unit that is based on the obtained light The luminous intensity information is used to evaluate an evaluation item selected from the group consisting of the presence, degree, and in-plane distribution of organic matter contamination on the surface of the semiconductor substrate to be evaluated.

According to the present invention, the presence, extent, and in-plane distribution of organic contamination on the surface of the semiconductor substrate can be evaluated. Further, by this, it is possible to estimate the cause of contamination of organic substances from the manufacturing apparatus of the semiconductor substrate or the storage container. According to push As a result of the measurement, process management such as device repair or container change to eliminate the cause of contamination is performed, whereby a high-quality semiconductor substrate having less organic contamination on the surface can be stably supplied.

1‧‧‧Laser light source

2‧‧‧half mirror

3‧‧‧Photoluminescence detector

4‧‧‧Autofocus detector

5‧‧‧Bandpass filter

6‧‧‧Input power meter

7‧‧‧Output power meter

8‧‧‧Surface scattered light detector

10‧‧‧Measurement device

W‧‧‧Semiconductor substrate

Fig. 1 is a schematic view of a measuring device according to a strong excitation microphotoluminescence method.

Fig. 2 is a schematic cross-sectional view showing a state in which a semiconductor wafer is housed in a semiconductor wafer shipping container used in the embodiment.

Fig. 3 is a view showing a map of the PL intensity obtained in the first embodiment in the upper part of Fig. 3, and a map outline of the contact angle measurement obtained in the first comparative example in the lower part of Fig. 3.

Fig. 4 is a graph showing the results of quantitative measurement of the amount of organic matter attached by GC-MS analysis.

One aspect of the present invention is a method for evaluating organic contamination on the surface of a semiconductor substrate, which comprises the following steps.

(1) obtaining photoluminescence intensity (PL intensity) information on the surface of the semiconductor substrate to be evaluated; and (2) evaluating the presence, degree, and in-plane of contamination from the organic substance on the surface of the semiconductor substrate to be evaluated based on the obtained PL intensity information An assessment item selected by the distribution of the group.

Hereinafter, each step will be described in order.

step 1)

In this step, PL intensity information is obtained on the surface of the evaluation target semiconductor substrate. As described above, in the organic substance adhering portion on the surface of the semiconductor substrate, the PL intensity is weaker than the unattached portion, and the more the adhesion amount, the weaker the PL intensity. Therefore, according to the PL intensity information obtained in this step, for example, it is judged that the portion where the PL intensity is weak is determined to be a portion where the organic substance adheres to the surface, and the weaker the PL intensity, the more the organic substance adhesion amount at the portion can be determined. many. Based on the in-plane distribution information of the PL intensity, the in-plane distribution of organic contamination can be evaluated. Further, the PL intensity obtained on the surface of the semiconductor substrate to be evaluated (for example, the average value, the maximum value, the minimum value, and the like of the PL intensity measured over the entire surface or a part of the area) is confirmed to be free from organic contamination. It is also possible to determine the presence or degree of organic contamination on the surface of the semiconductor substrate to be evaluated, as compared with the PL intensity obtained on the surface of the reference semiconductor substrate, which is less than the organic matter contamination. The PL intensity information of the present invention includes, as described above, the average value, the maximum value, the minimum value of the PL intensity, and the distribution information (in-plane distribution information) of the PL intensity of the entire surface or a part of the area. Various information about PL intensity.

The details of the determination will be described later in the step (2).

The evaluation target semiconductor substrate is, for example, a tantalum substrate, but is not particularly limited. For example, in a compound semiconductor substrate, the above evaluation method can also be applied. The conductivity type of the semiconductor substrate may be either p-type or n-type. Regardless of whether the semiconductor substrate to be evaluated is a semiconductor substrate of any conductivity type, the presence or absence of the organic contamination on the surface and the in-plane distribution can be evaluated with high sensitivity by the photoluminescence method. If the p-type is compared with the n-type, in the n-type, since the surface level of the electron-filled state in the state where no organic matter adheres is increased, and the organic matter is attached, the cause is not caused. Since the surface level of the electron filling caused by the mutual exclusion is small, the PL intensity difference caused by the difference in PL intensity between the organic substance attachment portion and the non-attachment portion or the difference in the adhesion amount is smaller than the p type. Therefore, in the p-type, the presence or degree or the in-plane distribution of organic matter contamination on the surface can be evaluated with higher sensitivity than the n-type. For example, in the case where the PL in-plane distribution information is obtained from the mapping profile, it is better to obtain a higher contrast mapping profile for higher sensitivity evaluation. Further, it is preferable to obtain a high-comparison PL in-plane distribution information from the viewpoint of easiness of evaluation.

The method for obtaining the PL intensity information of the present invention is not particularly limited as long as it is based on a photoluminescence method. From the viewpoint of ease of handling, it is preferred to carry out room temperature photoluminescence (room temperature PL method) which does not require temperature control. Taking the ruthenium substrate as an example, in the room temperature PL method, the electron hole pair (ie, the carrier) generated from the energy band gap of the erbium from the surface band of the test piece is generated near the surface by the excitation light having a large energy. The inside of the wafer diffuses and illuminates and gradually disappears. This luminescence is called band-end luminescence and represents an emission intensity of about 1.15 μm at a wavelength of room temperature (for example, 20 to 30 ° C). In general, in the photoluminescence method, since visible light can be used as the excitation light, if the light intensity of the wavelength of 950 nm or more is measured as the PL intensity, since it can be separated from the excitation light, measurement with high sensitivity can be realized. From this point, as the PL intensity, it is preferable to measure the intensity of the band end. Here, as described above, the organic material adhering portion on the surface of the semiconductor substrate has a decrease in the light-emitting intensity due to the band-biased accumulation side (p-type) or the inversion side (n-type). Therefore, depending on the presence or absence of adhesion of organic substances on the surface or To the extent, the difference in PL intensity occurs on the surface of the semiconductor substrate.

In the present invention, as an example of a device which can be used for measurement of PL intensity according to the room temperature PL method, a measurement method of a strong excitation microphotoluminescence method can be cited. Strongly excited microphotoluminescence method is used to stimulate the load in the sputum by visible laser The intensity of the luminescence (band-end luminescence) produced by the sub- and then excited carriers when recombined directly between the band gaps. Fig. 1 is a schematic diagram of a measuring device according to a strong excitation microphotoluminescence method, in Fig. 1, a 10 series measuring device, a 1 series laser light source, a 2 series half mirror, a 3 series photoluminescence detector 4 series autofocus detector, 5 series band pass filter, 6 series input power meter, 7 series output power meter, 8 series surface scattered light detector, W system measurement target test piece (semiconductor substrate). The measurement target test piece W is placed on an XY table (not shown), and the XY table is operated to excite the laser light to be scanned in the X direction and the Y direction of the substrate surface. Thereby, the PL intensity information of the semiconductor substrate to be evaluated is obtained. The PL intensity information can also be obtained from the entire surface of the surface of the evaluation specimen, or it can be obtained in part. Further, when the PL in-plane distribution information is acquired as the PL intensity information, the acquired in-plane distribution information may be a line contour of the PL intensity or a mapping contour. In order to evaluate the presence, extent, and distribution of organic matter attachment throughout the in-plane, it is preferred to obtain a mapping profile. In mapping the contour, by assigning the high to low of the PL intensity, for example, the black-to-white brightness (the degree of shading), the PL intensity can be evaluated based on the brightness of the mapped image. Further, in the present invention, the in-plane distributed information is not limited to the distribution information of the entire surface in the plane, but is used to mean the distribution information of the partial regions also included in the plane. For example, the PL intensity information (for example, the average value, the maximum value, and the minimum value of the PL intensity) in a certain area in the plane and the PL intensity information of the other one or more areas in the plane are also included in the PL in-plane distribution information. Made.

Step (2)

This step evaluates the evaluation item selected from the group consisting of the presence, absence, and in-plane distribution of organic matter contamination on the surface of the semiconductor substrate to be evaluated, based on the PL intensity information obtained by the step (1). In one form, in the acquisition The PL intensity information (for example, the above-mentioned PL in-plane distribution information) can determine that organic matter contamination occurs on the surface of the germanium wafer according to the difference in the strength of the PL (more specifically, local organic contamination occurs), and In another aspect, as described in the foregoing, by comparing the obtained PL intensity information with the PL intensity information obtained for the reference semiconductor substrate, it is possible to determine the presence or absence of adhesion of the organic substance on the surface of the evaluation target semiconductor substrate or The degree of pollution (contamination is severe or mild). Further, in another aspect, the information is distributed in the PL plane obtained in the step (1), and it is determined that the organic matter contamination occurs in the region where the PL intensity is low, and the in-plane distribution of the organic matter contamination on the surface can be evaluated.

In the evaluation method described above, since the in-plane distribution can be evaluated not only in the presence or absence of contamination of the organic substance on the surface of the semiconductor substrate to be evaluated, it is also possible to estimate the cause of organic contamination on the surface of the semiconductor substrate. In this regard, as a reason for the occurrence of organic contamination of the semiconductor substrate, the adhesion of the organic gas substance deaerated from the manufacturing apparatus or the storage container of the semiconductor substrate, the constituent materials of the device or the container, and the semiconductor substrate are exemplified. When the surface is in contact with, it adheres to or adheres to the organic gas substance of the environmental gas inside the device or the container. For example, if information is distributed in the PL plane and the area where the PL intensity is locally lowered is confirmed, it is presumed that the member located in the vicinity of the area or the member to be contacted is the cause of organic contamination on the surface in the manufacturing apparatus or the storage container. Alternatively, it is presumed that the organic gas substance of the environmental gas mixed in the manufacturing apparatus or the storage container is a cause of contamination, as compared with the reference semiconductor substrate which is free from contamination (or very little pollution), and it is confirmed that the PL intensity is substantially uniformly decreased over the entire area. .

Therefore, according to one aspect of the present invention, by using the above-mentioned evaluation party The method can also evaluate the presence or degree of occurrence of organic contamination caused by the manufacturing apparatus or the storage container of the semiconductor substrate.

That is, one aspect of the present invention is an evaluation method of a device in which a semiconductor substrate is disposed during production or storage, and is configured to acquire PL intensity information on a surface of a semiconductor substrate disposed on the device, and to obtain PL intensity according to the obtained Information to evaluate an evaluation item of a group selection consisting of the presence or absence of the occurrence of organic contamination on the surface of the semiconductor substrate caused by the device. The details of the assessment are as shown in the previous section. Further, examples of the device to be evaluated include a storage container for a semiconductor substrate and various devices (for example, a heat treatment furnace) for arranging a semiconductor substrate in a process.

As described above, it is possible to estimate the cause of organic contamination on the surface of the semiconductor substrate based on the in-plane distribution information of the PL. This means the occurrence of organic contamination on the surface of the semiconductor substrate caused by the device in which the semiconductor substrate is placed during manufacture or storage. The details of the speculation are as shown in the previous section. Further, in order to reduce or eliminate the cause of the estimation, it is possible to provide a semiconductor substrate having less organic contamination on the surface by performing a pollution reduction treatment such as replacement, repair, and cleaning of the manufacturing apparatus and the storage container.

Moreover, another aspect of the present invention relates to a method of manufacturing a semiconductor substrate, comprising: preparing a batch for preparing a semiconductor substrate composed of a plurality of semiconductor substrates; and extracting a step of extracting at least one semiconductor from the batch a substrate; an evaluation step of evaluating the extracted semiconductor substrate; and at least one semiconductor substrate selected from the group consisting of the semiconductor substrate on which the good product is evaluated and the other semiconductor substrate in the same batch as the semiconductor substrate The product substrate is shipped, or the defective product is judged from the evaluation At least one semiconductor substrate selected from the group consisting of a semiconductor substrate and another semiconductor substrate in the same batch of the semiconductor substrate is subjected to a cleaning process to reduce contamination of the surface organic matter, and then shipped as a product substrate; An evaluation method of organic contamination on the surface of a semiconductor substrate of one form evaluates the extracted semiconductor substrate.

According to the method for evaluating organic contamination on the surface of a semiconductor substrate according to one aspect of the present invention described above, organic contamination of the surface of the semiconductor substrate can be evaluated with high sensitivity and high resolution. Therefore, in one form, by the evaluation method, the presence or absence of the organic matter contamination on the surface to be judged, the in-plane distribution state is a semiconductor substrate which can be used to manufacture a good quality component, or a semiconductor in the same batch as the substrate. Since the substrate is shipped as a product substrate, it is possible to provide a product substrate capable of producing a high-quality component with high reliability. Further, the basis for the judged good product can be set in consideration of the physical properties obtained by the substrate in consideration of the use of the semiconductor substrate or the like. Further, the number of substrates included in one batch and the number of substrates to be extracted may be appropriately set.

Further, in another aspect, as a result of the evaluation, the semiconductor substrate of the defective product that is determined to be the basis for determining the quality of the defective product or the other semiconductor substrate in the same batch as the semiconductor substrate of the defective product is subjected to the cleaning process. After reducing the organic contamination on the surface, it is shipped as a product substrate, thereby providing a product substrate capable of producing a high-quality component with high reliability. The washing treatment can be carried out according to a known method. Further, the semiconductor substrate after reducing the organic contamination on the surface can be directly shipped as a product substrate, and can be shipped as a product substrate after confirming that it is a good product by the above evaluation method.

Another aspect of the invention relates to a semiconductor substrate The apparatus for evaluating organic matter contamination on a surface includes: a measuring unit that acquires PL intensity information on a surface of the semiconductor substrate to be evaluated; and an evaluation unit that evaluates an organic substance from a surface of the semiconductor substrate to be evaluated based on the obtained PL intensity information An assessment of the choice of population consisting of the presence, extent, and in-plane distribution of pollution. The evaluation device can be adapted for use in the evaluation methods described above.

As the measuring unit included in the evaluation device, a conventional photoluminescence measuring device such as a photoluminescence measuring device on the market can be used without limitation. An example of the measuring device is as described above. Further, in the evaluation device, the measuring unit and the evaluation unit described later may be included as another constituent element, or may be included as an integral constituent element. The details of the PL intensity information acquired by the measuring unit are as described above.

The evaluation unit may include at least a display unit that can display the PL intensity information acquired by the measurement unit. In one aspect, the evaluator can determine the PL intensity information displayed on the display unit by visually determining the PL intensity information displayed on the display unit. The present invention is not limited to the following aspects. However, as a specific aspect, it is possible to estimate the mapping contour by visual observation and whether or not the difference between the maximum value and the minimum value of the PL intensity in the plane exceeds the threshold value and the surface. Evaluation of whether or not the average value of the PL intensity in the range exceeds the threshold value, and whether the PL intensity of the specific region where the possibility of contamination of the organic matter on the surface caused by the manufacturing apparatus or the storage container exceeds the threshold value is judged as a criterion. Wait.

[Examples]

Hereinafter, the present invention will be further described based on examples. However, the present invention is not limited to the embodiment shown in the examples. The evaluations described below were carried out at room temperature (about 20 ° C).

Prepare the evaluation object 矽 wafer

Three levels of boron-doped p-type germanium wafers of the following three levels were prepared for each level. One of the same level is based on the PL method, the other one is based on the GC-MS method, and the remaining one is evaluated according to the contact angle method. The details of the assessment will be described later. All of the wafers are manufactured in the same batch. Therefore, the difference in the evaluation results between the levels can be judged as the influence due to the difference in the evaluation method or the pollution at the time of storage.

<Evaluation target 矽 wafer>

Reference wafer: A wafer that has just been cleaned before shipment.

Wafer 1: After cleaning the same wafer as the reference wafer, the wafer was stored in a semiconductor wafer shipping container for one month.

Wafer 2: After being cleaned before shipping as in the reference wafer, it is stored in a semiconductor wafer shipping container different from the semiconductor wafer shipping container used for the storage of the wafer 1 for 3 months.矽 Wafer.

Fig. 2 is a cross-sectional view showing a semiconductor wafer shipment container in a state in which a wafer is housed.

[First Embodiment]

Evaluation according to the room temperature PL method

As a device shown in Fig. 1, a Si measuring device, a Si measuring device manufactured by Nanometrics Co., Ltd., was used, and as a measuring laser, a reference light, a wafer 1 and a wafer 2 were used at a pitch of 500 μm using a light source having a wavelength of 532 nm. Band photoluminescence intensity map measurement.

In the upper part of Fig. 3, the mapping outline of the PL intensity of the reference wafer, the wafer 1 and the wafer 2 is shown. In the mapping outline, the lower the PL intensity is displayed The darker (black), the higher the part is shown as brighter (white). In the map outline shown in the upper part of Fig. 3, the in-plane upper side indicates that the semiconductor wafer shipping container is disposed above (notched side), and the in-plane lower side indicates that the semiconductor wafer shipping container is disposed below. result. In the mapping profile of the wafer 1 and the wafer 2, the decrease in the PL intensity was confirmed in the area disposed above and below the surface, and the wafer 2 having a long period of storage during the storage period of the semiconductor wafer shipment container was observed to have a more severe PL intensity. The reduction. In contrast, in the reference wafer, it was confirmed that there was no such decrease in PL intensity, and the PL intensity was substantially the same over the entire area in the plane.

From the above results, it can be inferred that the wafer 1 and the wafer 2 are in the semiconductor wafer shipping container, and the organic contamination source on the surface exists in the vicinity of the wafer, and is in the semiconductor wafer shipping container in the wafer surface. The reason for the decrease in PL intensity occurs in the area located above. Among the constituent members of the semiconductor wafer shipment container, a spacer (sealing member) is exemplified as a member that can cause contamination of the organic substance only above. From the above, it is speculated that the gasket of the semiconductor wafer shipment container is the cause of organic contamination on the surface.

Identification of attached organic matter by GC-MS and confirmation of the amount of organic matter attached

By heating the reference wafer, the wafer 1 and the wafer 2, the organic matter adhering to the surface of the wafer is vaporized and recovered. The recovered organic matter was analyzed by gas chromatography mass spectrometry (GC-MS). From the mass spectrum of the GC-MS, it was confirmed on the wafer 1 and the wafer 2 that the organic substance derived from the plasticizer contained in the gasket of the semiconductor wafer shipment container. It is considered that the plasticizer is degassed and adhered to the wafer 1 and the wafer 2.

From the calibration curve made using standard materials, attached to the crystal The amount of the organic matter in the circle 1 and the wafer 2 was quantitatively measured. The result is shown in Fig. 4. Further, the organic matter was not detected from the organic solvent that had washed the reference wafer. In the gas chromatography analysis, it is possible to quantify the organic matter attached to the surface of the semiconductor substrate, but it is difficult to obtain the in-plane distribution information of the organic contamination of the surface. On the other hand, according to the PL method, as shown in the first embodiment, it is possible to obtain in-plane distribution information of organic matter contamination on the surface. Further, based on the in-plane distribution information of the organic matter contamination on the surface, it is also possible to estimate the cause of the organic contamination on the surface. From this point of view, the evaluation method according to the PL method is also an excellent method.

As a specific form of the evaluation method, for example, since the contrast profile of the PL intensity of the wafer 1 and the wafer 2 is confirmed in the plane as shown in FIG. 3, it can be determined that organic matter occurs on the wafer 1 and the wafer 2. Pollution. Further, for each wafer of the wafer 1 and the wafer 2, the average value of the PL intensity in one portion of the wafer surface (for example, in the in-plane direction) and the PL in the other portion (for example, in-plane) are calculated. The average value of the intensity is because the average value of the PL intensity in one region is lower than the average value of the PL intensity in one of the other partial regions, so it can be determined that organic matter contamination occurs in one region (for example, in-plane). Alternatively, the average value of the PL intensity in the plane is calculated for the wafer 1, the wafer 2, and the reference wafer, and is calculated for the wafer 1 and the wafer 2 compared with the average value calculated for the reference wafer. Since the average value is low, it is also possible to determine that organic matter is contaminated on the wafer 1 and the wafer 2. Further, since the average value calculated for the wafer 1 is lower than the average value calculated for the wafer 2, since the average value calculated for the wafer 2 is lower, it can be determined that the wafer 2 is crystallized at the surface. Round 1 serious organic pollution.

[First Comparative Example]

Evaluation based on contact angle measurement

Based on this evaluation, it is speculated that the gasket of the semiconductor wafer shipment container is the cause of organic contamination on the wafer surface. Therefore, in the surface of the reference wafer, the wafer 1 and the wafer 2, the contact angle on the market surface is taken at a plurality of points in the plane centered on the in-plane region located above the semiconductor wafer shipping container. A measuring device measures the contact angle with water. The greater the contact angle with water, the less the amount of organic matter attached can be determined. The lower part of Fig. 3 shows the mapping contour obtained by color scaling the measured values.

In the map profile of the contact angle measurement shown in the lower part of Fig. 3, it is impossible to confirm the apparent contrast difference in the plane of the PL contour obtained as in the first embodiment.

From the above results, according to the PL method, it can be confirmed that the organic matter contamination on the surface of the semiconductor wafer can be evaluated with higher sensitivity than the contact angle measurement.

[Industrial Applicability]

The present invention is useful in the field of manufacturing semiconductor substrates.

1‧‧‧Laser light source

2‧‧‧half mirror

3‧‧‧Photoluminescence detector

4‧‧‧Autofocus detector

5‧‧‧Bandpass filter

6‧‧‧Input power meter

7‧‧‧Output power meter

8‧‧‧Surface scattered light detector

10‧‧‧Measurement device

W‧‧‧Semiconductor substrate

Claims (10)

A method for evaluating organic matter contamination on a surface of a semiconductor substrate, comprising: obtaining photoluminescence intensity information on a surface of the semiconductor substrate of the evaluation object; and, based on the obtained photoluminescence intensity information, by evaluating the photoluminescence intensity, evaluating the evaluation An evaluation item for group selection consisting of the presence or absence, degree, and in-plane distribution of organic matter contamination on the surface of the target semiconductor substrate. The method for evaluating organic matter contamination on a surface of a semiconductor substrate according to claim 1, wherein the photoluminescence intensity information includes in-plane distribution information of a photoluminescence intensity on a surface of the semiconductor substrate to be evaluated. For example, the method for assessing the contamination of organic matter in claim 1 or 2 further includes at least an assessment of the in-plane distribution of organic contamination, and based on the evaluation results obtained, the cause of the organic contamination on the surface is presumed. The method for evaluating organic matter contamination according to claim 1 or 2, wherein the semiconductor substrate is a p-type semiconductor substrate. A method for evaluating a device, which is a method for evaluating a device in which a semiconductor substrate is disposed during manufacture or storage, comprising: obtaining photoluminescence intensity information on a surface of a semiconductor substrate disposed on the device; and obtaining a photoluminescence intensity according to the obtained photoluminescence intensity Information, by the weakening of the photoluminescence intensity, evaluates the evaluation items of the group selection consisting of the presence or absence of organic contamination on the surface of the semiconductor substrate of the device. The method of evaluating a device according to claim 5, wherein the photoluminescence intensity information comprises in-plane distribution information of photoluminescence intensity of a surface of the semiconductor substrate disposed on the device. The evaluation method of the device of claim 6 further includes estimating the cause of organic contamination on the surface of the semiconductor substrate of the device based on the in-plane distribution information of the photoluminescence intensity. The evaluation method according to any one of claims 5 to 7, wherein the device is a storage container for a semiconductor substrate. A method of manufacturing a semiconductor substrate, comprising: preparing a batch for preparing a semiconductor substrate composed of a plurality of semiconductor substrates; and extracting a step of extracting at least one semiconductor substrate from the batch; and evaluating step of evaluating the extracted semiconductor substrate And at least one semiconductor substrate selected from the group consisting of the semiconductor substrate on which the good product is evaluated and the other semiconductor substrate in the same batch of the semiconductor substrate is shipped as a product substrate, or is At least one semiconductor substrate selected from the group consisting of the semiconductor substrate of the defective product and the other semiconductor substrate in the same batch of the semiconductor substrate is subjected to a cleaning process to reduce the organic contamination on the surface, and then shipped as a product substrate; The method of any one of claims 1 to 4 evaluates the drawn semiconductor substrate. An apparatus for evaluating organic matter contamination on a surface of a semiconductor substrate, comprising: a measuring unit that obtains photoluminescence intensity information on a surface of the semiconductor substrate to be evaluated; and an evaluation unit that is based on the obtained photoluminescence intensity information by using light The luminescence intensity is weakened, and the organic matter from the surface of the semiconductor substrate to be evaluated is evaluated An assessment of the choice of population consisting of the presence, extent, and in-plane distribution of pollution.