JPH11145233A - Evaluation of semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide at high speed a method for quantitatively evaluating a surface state of a semiconductor element. SOLUTION: Light of a xenon lamp is irradiated on the surface of a semiconductor silicon substrate through a polarizer, reflected light is passed through the analyzer, spectrally divided through a prism, spectrally separated light is received by a spectrum sensor, light quantity data received by the sensor is sent to a computer to calculate with use of the data, the thickness and absorption coefficient of an oxide film formed on the silicon substrate. Subsequently, the substrate surface is subjected to a desired processing operation, the light of the xenon lamp is illuminated on the substrate surface through the polarizer, reflected light is passed through the analyzer and through the prism for spectral separation, spectrally separated light is received by the spectrum sensor, light quantity data received by the sensor is sent to the computer to be calculated with the use of the data, thickness and absorption coefficient of a second film formed on the silicon substrate, and to compare the thickness and absorption coefficient of the oxide film with those of the second film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for evaluating the surface of a semiconductor device.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of semiconductor devices, it has become important to grasp the surface condition of the device. As a method for evaluating the surface condition, observation of the surface using an optical microscope or a scanning electron microscope, or cleavage of the device is performed. Then, a method of observing a cross section with a scanning electron microscope is used.

A conventional method for evaluating the surface of a semiconductor device will be described below. FIG. 4 is a flowchart showing a cross-sectional evaluation method using a scanning electron microscope. The operation of the method configured as shown in FIG. 4 will be described below.

[0004] First, a semiconductor element is cleaved to obtain a section to be observed. At this time, the element is cleaved to a size enough to enter the sample chamber of the electron microscope, that is, a small size of about 1 to 2 cm square. Next, the sample is put into a sample chamber of an electron microscope, and a section to be observed is searched for and displayed on a screen. Then, 10 is displayed on the screen.
The surface of the element appears at a magnification of up to 200,000 times. Then, while observing the screen, move it little by little and observe the state of the surface.

[0005]

However, in the above-described conventional configuration, since observation was not possible unless the sample was destroyed, there was a problem that a change in the surface of the sample could not be observed by performing additional processing. In addition, it is extremely difficult and time-consuming to obtain a desired cross section to be observed when cleaving the sample. It takes a very long time to observe the sample in the sample chamber of the electron microscope, and only a small part of the sample can be observed. Furthermore, there is a problem that the method is not a quantitative evaluation method because it is only an evaluation based on observation.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a method for evaluating a semiconductor device which can non-destructively and quantitatively evaluate a sample in a short time. .

[0007]

In order to achieve this object, a method for evaluating a semiconductor device according to the present invention comprises irradiating a surface of a semiconductor silicon substrate with light from a xenon lamp through a polarizer and analyzing light reflected from the substrate surface with an analyzer. Through the prism and then through the prism, receive the separated light with the spectrum sensor, send the light quantity data received by the spectrum sensor to the computer, and use this data to determine the thickness and absorption of the oxide film formed on the silicon substrate. Calculate the coefficient, apply the desired treatment to the surface of the semiconductor silicon substrate, irradiate the surface of the substrate with the light of a xenon lamp through a polarizer, pass the reflected light from the substrate surface through an analyzer, and then spectrally separate it through a prism. The received light is received by the spectrum sensor, and the light amount data received by the spectrum sensor is collected. Feeding the computer, using the data, the film thickness and the absorption coefficient of the film produced on a silicon substrate was calculated, is characterized in that compared with the thickness and the absorption coefficient of the previous oxide film.

With this configuration, the surface state can be known only by subjecting the sample to a desired process, irradiating the lamp with light, and then calculating the light amount data by a computer. Quantitative evaluation can be performed over a wide range in a short time.

[0009]

FIG. 1 is a flowchart showing a method for evaluating the surface state of a semiconductor device according to an embodiment of the present invention.

First, the surface of a semiconductor silicon substrate is irradiated with light from a xenon lamp through a polarizer, the reflected light is passed through an analyzer, and then is separated through a prism, and the light is received by a spectrum sensor. To calculate the thickness and absorption coefficient of the oxide film formed on the silicon substrate.

Subsequently, as shown in FIG. 2, the surface of the semiconductor silicon substrate 3 is subjected to a dry etching process 1.
As a result, the damage layer 2 is formed on the silicon substrate surface.
Is given. This is a disorder and alteration of the arrangement of silicon atoms, and the 5 nm generated on the silicon substrate shown in FIG.
A degree of amorphous layer 4 can be considered.

Next, the light of the xenon lamp is irradiated through a polarizer, the reflected light from the substrate surface is passed through an analyzer, and then the light is separated through a prism and received by a spectrum sensor. Calculate the film thickness and absorption coefficient of the film generated above.

The thickness and absorption coefficient of the film thus determined reflect the damage of dry etching.
By comparing this with the already determined thickness of the oxide film and the absorption coefficient, the quantitative characteristics of the damaged layer can be known. For example, when the conditions of dry etching are changed, a change in surface state can be easily known by this method, and quantitative comparison of dry etching conditions becomes easy.

As described above, according to the present embodiment, the film thickness and absorption coefficient of the oxide film are compared with the film thickness and absorption coefficient of the film formed by the damage of the dry etching, so that the surface state of the oxide film is improved. Evaluation can be performed, and damage of dry etching can also be evaluated.

In the above-described embodiment, dry etching is performed as a process for damaging the surface. However, instead of this process, ion implantation, cleaning, and ashing can provide the same effects as described above. Needless to say.

[0016]

According to the present invention, the surface state is evaluated by comparing the thickness and absorption coefficient of the oxide film before dry etching with the thickness and absorption coefficient of the film formed after dry etching. Thus, it is possible to realize an excellent method for evaluating the surface state of a semiconductor device. Compared with the cross-sectional observation using a scanning electron microscope, which is a conventional evaluation method, it is possible to perform quantitative evaluation in a very short time.

Also, it is possible to realize an excellent method for evaluating the surface condition of a semiconductor device, which can simultaneously evaluate the damage of dry etching.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method for evaluating a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a process of damaging a silicon substrate according to the embodiment of the present invention.

FIG. 3 is a diagram showing a sample in which an amorphous layer is generated after damaging a silicon substrate according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a conventional semiconductor device evaluation method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dry etching process 2 Damage layer given by dry etching process 3 Silicon substrate 4 Amorphous layer

Claims (5)

[Claims] 1. A surface of a semiconductor silicon substrate is irradiated with light of a xenon lamp through a polarizer, reflected light of the irradiated light from the substrate surface is passed through an analyzer, and subsequently separated through a prism, and the separated light is analyzed by a spectrum sensor. Receiving the amount of light received by the spectrum sensor to a computer and convert it into data, using the data to calculate the thickness and absorption coefficient of an oxide film formed on the silicon substrate, Performing the treatment, irradiating the surface of the substrate with light of a xenon lamp through a polarizer, passing the reflected light of the irradiating light from the substrate surface through an analyzer, and subsequently separating the light through a prism, receiving the separated light with a spectrum sensor, Send the amount of light received by the spectrum sensor to a computer and convert it to data Calculating a film thickness and an absorption coefficient of a film formed on the silicon substrate using the data, and comparing the film thickness and the absorption coefficient with a film thickness and an absorption coefficient of the oxide film; A method for evaluating the surface state of a semiconductor element. 2. The method according to claim 1, wherein dry etching is performed as a desired process. 3. The method according to claim 1, wherein ion implantation is performed as a desired process. 4. The method according to claim 1, wherein cleaning is performed as a desired process. 5. The method for evaluating a semiconductor device according to claim 1, wherein ashing is performed as a desired process.