JP3283852B2 - Evaluation device for semiconductor wafer characteristics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for evaluating characteristics of a semiconductor wafer, and more particularly, to a non-contact, non-destructive measurement of a surface recombination velocity and a bulk lifetime of each surface or one side of a semiconductor wafer. It relates to an evaluation device.

[0002]

2. Description of the Related Art With the miniaturization of circuit patterns such as ULSI, high quality single crystals are required for silicon wafers serving as substrates thereof. In particular, there is a strong demand for reduction of defects in heavy crystals and heavy metal contamination contained in silicon wafers.

On the other hand, there is a strong demand for the enhancement of the surface and surface layer of a wafer constituting a key structure of a semiconductor device, for example, a MOS gate oxide film and an interface between the MOS gate oxide film and the substrate. Furthermore, not only silicon oxide (SiO ₂ ) but also new materials such as silicon nitride (SiN), tantalum oxide (Ta ₂ O ₅ ), and aluminum oxide (Al ₂ O ₃ ) have been tried for the gate dielectric. I have. In addition, there is an issue of evaluating the interface between a semiconductor having an SOI structure and an insulator, which will be a future semiconductor device. The surface and interface crystal qualities due to these new materials and new structures require particularly high quality characteristics. Furthermore, a new problem due to the adoption of a new manufacturing process required for producing each of the above-mentioned materials is considered, and the evaluation of the interface between the surface layer and the substrate is becoming more and more important together with the process evaluation.

The bulk lifetime evaluates the crystallinity of the substrate of the semiconductor wafer, and the surface recombination rate evaluates the surface or interface state. Therefore, it has become an essential condition for semiconductor evaluation to clearly separate and evaluate the bulk lifetime and the surface recombination velocity.

[0005]

Conventionally, lifetime evaluation methods have been widely used for evaluating crystals because of their extremely high sensitivity to defects, metal contamination, surface characteristics, and damage. JIS H 0604 and AS
According to TM F28 standard, AST is used for semiconductor wafer measurement.
Each measurement method is standardized in the MF 1535 standard. Some devices are commercially available as lifetime measuring devices. The measurement method according to JIS H 0604 and ASTM F28 standard is not a method of measuring the shape of a semiconductor wafer as it is, but a method of cutting and using a material in a square rod shape according to the standard. The measurement result is not the bulk lifetime τ _b but the apparent lifetime τ _a including the surface recombination velocity.

[0006] The ASTM F 1535 standard is a measurement in a wafer shape as it is, but is not a measurement in which the surface recombination velocity and the bulk lifetime are clearly separated. In order to measure the bulk lifetime, it is necessary to perform thermal oxidation on the surface of the wafer depending on the surface state and measure the surface recombination speed sufficiently low. Alternatively, it is specified that the measurement is performed by immersing a semiconductor wafer in a chemical passivation solution such as an iodine alcohol solution.

On the other hand, even with a similar measuring device on the market, it is not possible to separately measure the surface recombination velocity and the bulk lifetime as described above. Therefore, when measuring the bulk lifetime, the same surface passivation as described above must be performed. Performing thermal oxidation requires at least several hours and man-hours in the manufacturing process, which can also introduce new contamination from process equipment.

In addition, the semiconductor wafer immersed in the solution cannot be reused or resold, in addition to its man-hour and time. This results in an economic loss in the case of expensive large-diameter wafers in the future, and also poses a problem in terms of effective use of resources.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the bulk lifetime and the surface recombination speed on each side or one side of a wafer without performing any processing on the wafer. An object of the present invention is to provide a semiconductor wafer characteristic evaluation apparatus which enables non-contact, non-destructive and separate measurement.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a semiconductor wafer characteristic evaluation apparatus for irradiating a semiconductor wafer with excitation energy, measuring the lifetime of generated carriers, and evaluating the quality of the semiconductor wafer. The above object , the same wavelength on both sides of the semiconductor wafer or
Irradiation with excitation light of a different wavelength or the semiconductor wafer
Excitation light of different wavelength is sequentially irradiated on the same part on one side of the wafer
An excitation light source, an antenna for emitting an electromagnetic wave to measure the impedance of the semiconductor wafer, an electromagnetic wave oscillator for supplying an electromagnetic wave to the antenna via a circulator and an impedance adjusting unit, and a signal from the antenna for the circulator. And a signal processing circuit for separately measuring the surface recombination speed and bulk lifetime of the semiconductor wafer.

Further, the semiconductor wafer is turned upside down.
Providing a front and back reversing mechanism to irradiate the excitation light on one side of the semiconductor wafer for measurement, and then inverting the semiconductor wafer and irradiating the same portion on the opposite side for measurement, the above object is more effective. Is achieved. Furthermore, the frequency of the electromagnetic wave oscillator is variable, and a bias light source is provided, or when a bias light source is provided, the excitation light source and the bias light source may be formed as an integral structure. A structure having a size sufficiently smaller than the wavelength, an LC resonance circuit in which a capacitor is connected to an open end of a circular or arbitrary-shaped conductor loop, a tap provided on the conductor loop, and power supply from the tap. Thereby, the above object is achieved more effectively.

[0012] Furthermore , a steady state without irradiating the excitation light.
The conductivity of the semiconductor wafer is estimated by measuring the impedance of the state, and the intensity of the excitation light irradiated at the time of measurement is controlled according to the conductivity.
The above purpose can be more effectively achieved by keeping the
This can be achieved more effectively by mapping and displaying the measured surface recombination velocity and bulk lifetime distribution of each surface of the semiconductor wafer individually on a display device.

On the other hand, an excitation light source for irradiating excitation light to both front and back surfaces or one surface of a semiconductor wafer, a first antenna for emitting electromagnetic waves to one surface of the semiconductor wafer, and an electromagnetic wave oscillator for supplying electromagnetic waves to the first antenna And a second antenna for measuring the impedance of the semiconductor wafer, and a signal from the second antenna is input via an impedance adjustment unit, and a surface recombination speed and a bulk lifetime of the semiconductor wafer are determined. The above object is also achieved by providing a signal processing circuit for separate measurement.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a semiconductor wafer is irradiated with excitation light (for example, laser light) under different excitation conditions to excite excess carriers under different excitation conditions in the semiconductor wafer, Irradiate electromagnetic waves,
A change in conductivity due to excess carriers is detected as a change in impedance of the semiconductor wafer. Utilizing the difference due to the excitation condition of the detected signal waveform, the surface of the semiconductor wafer,
Alternatively, when the same or different material is attached to the surface or when the surface is treated, the surface recombination rate and the bulk lifetime of the interface are separately measured.

The measurement principle used in the evaluation apparatus of the present invention is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-54338. That is, one surface and / or the other surface of the semiconductor wafer is irradiated with a light beam or an electron beam, and at least two types of excess carriers that are instantaneously excited by the irradiation of the light beam or the electron beam due to a difference in carrier excitation conditions. A method for separately measuring a surface recombination speed of one surface of a semiconductor wafer, a surface recombination speed of the other surface, and a bulk lifetime by detecting a change in conductivity of a semiconductor wafer based on different spatial distributions. It is. No apparatus for implementing such a measuring method has yet emerged, and the excitation light source, optical system and components used in this measuring method, including their dimensions and prices, can be economically accepted in the market even if manufactured. It was difficult.

On the other hand, as semiconductor IC technology advances and IC circuit patterns become finer, the demand for high quality wafers increases, and the need for semiconductor wafers having high quality crystal surfaces, interface states, and bulk characteristics is increasing. I'm growing. As a result, the necessity of accurately measuring the bulk crystal state, surface state, and interface state between the bulk and the surface layer of a semiconductor wafer increases, and there is a strong market demand for an evaluation device capable of clearly separating and measuring these. became. The present invention can answer such a request.

Hereinafter, an evaluation apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an evaluation apparatus according to the present invention, and FIGS. 2A to 2D show a procedure for processing a measurement signal. FIG. 2A shows a state where the semiconductor wafer 1 is irradiated with excitation light such as laser light.
(b) the measurement signal of the surface, FIG. (c) shows the back surface of the measurement signal, respectively, and FIG. (d) of the bulk lifetime tau _b and the recombination rate S _O of the front and back surfaces, the S _W It is a figure showing the flow of measurement.

As shown in FIGS. 1 and 2 (a), the front and back surfaces of the semiconductor wafer 1 having a thickness W are formed on the excitation light sources 2a-1 and 2a.
with the center wavelength λ sequentially momentarily illuminated in the _first excitation light from a-2, the irradiation time, the intensity is controlled by each of the excitation light sources 2a-1 and 2a-2 source drive circuit 3a-1 and 3a-2 It is supposed to be. The semiconductor wafer 1 is held by a wafer holding mechanism 6, and the position of the wafer holding mechanism 6 is controlled by a driving mechanism 7. Position control is performed by XY of rectangular coordinate drive or r-θ of polar coordinate drive, and bias light sources 5-1 and 5-2 are further provided on both front and back surfaces of the semiconductor wafer 1 to irradiate bias light. It has become. An antenna 4 provided in the vicinity of the semiconductor wafer 1 is provided with a circulator 9 and an impedance adjuster 8 by an electromagnetic wave oscillator 10.
An electromagnetic wave is supplied via the antenna 4, and the electromagnetic wave is radiated from the antenna 4 to the semiconductor wafer 1. Excess carriers are excited in the semiconductor wafer 1 irradiated with the excitation light, whereby the conductivity of the semiconductor wafer 1 changes. A change in the electrical conductivity in the semiconductor wafer 1 is detected by the antenna 4 as a change in the wafer impedance, is route-controlled by the circulator 9 via the impedance adjusting unit 8, and is detected by the detector 11. The detected signal is amplified by an amplifier 12, converted to a digital signal by an A / D converter 13, and sent to a CPU 14. The impedance adjusting unit 8 adjusts the impedance including the antenna 4 and the semiconductor wafer 1 so as to conform to the measurement conditions. Means can be used.

An excitation light source 2a-
If instantaneously excited at the center wavelength lambda ₁ of pump light from 1, the temporal variation of the detection signal after turning off the excitation light 2
It becomes like the solid line of (b). Next, the same measurement is performed by irradiating the back surface of the semiconductor wafer ₁ with excitation light having the same center wavelength λ1 from the excitation light source 2a-2. The temporal change of the detected signal in this case is as shown by the solid line in FIG.

Next, a method of processing a measurement signal will be described. In FIG. 2 (a), S ₀ is the surface recombination velocity of the surface of the semiconductor wafer 1, S _w is the back surface of the surface recombination velocity, tau _b represents the bulk lifetime respectively, and FIG. 2 (b) as well as
The vertical axis in (c) is a logarithmic scale. Since a signal tail portion after a sufficient time elapses approaches an exponential function, it can be approximated by a straight line on semilogarithmic coordinates. The time when the excitation light is turned off is set to time zero, and the measurement signals on the front and back surfaces at this time are set to σ ₀ (0) and σ _w (0), respectively. In addition, the approximate straight line is extended, and the intersection with the time zero axis is set to σ ₀₁ (0),
Let σ _w1 (0). From the measurement signals σ ₀ (0) and σ _w (0) and the intersection points σ ₀₁ (0) and σ _w1 (0), the surface recombination speeds S ₀ and S _w of the front and back surfaces of the semiconductor wafer 1 are obtained. Surface recombination speed S ₀
And calculation formula for obtaining the S _w, for example JP 57-543
The formula described in No. 38 is applied. Next, the bulk lifetime in the procedure as shown in FIG. 2 (a) and the slope tau _a approximate straight line in (b), FIG from the previous to the surface recombination velocity S ₀ obtained, S _w 2 (d) Find τ _b . The formula for calculating the bulk lifetime τ _b is described in, for example,
Apply the formula described in the item. As described above, the surface recombination speeds S ₀ , _Sw and the bulk lifetime τ _b of the front and back surfaces of the semiconductor wafer 1 are obtained.

By irradiating the background light during the measurement with the bias light sources 5-1 and 5-2 in FIG. 1, the influence of the trap in the semiconductor wafer 1 on the measurement can be avoided. The drive mechanism 7 moves the wafer holding mechanism 6 (semiconductor wafer 1) to the rectangular coordinate X.
The measurement points are sequentially moved by moving along −Y or the polar coordinates r−θ coordinates, so that the distribution measurement at an arbitrary point in the semiconductor wafer 1 or in the wafer plane is possible.

Next, measurement examples according to the present invention will be sequentially described.

A CZ silicon single crystal, n-type, (100) plane, a mirror-finished wafer having a resistivity of 10 Ω to 20 Ω was used, and the back surface of the wafer was sealed with a polysilicon film. The measurement was performed after forming a silicon oxide layer on the mirror-surface wafer by thermal oxidation. The measured waveforms were as shown in FIG. 3A for the front side irradiation, and as shown in FIG. 3B for the back side irradiation. The measurement results are shown in the column of “Polysilicon back surface seal” in Table 1.

[0025]

[Table 1] The recombination speed S _o of the front surface is very low at “40”, but the recombination speed S _w of the back surface is very high at “4027”. The high recombination rate is considered to be due to the presence of a large number of recombination centers at the interface between silicon and polysilicon and the grain boundaries of polysilicon. Thus, the recombination rate at the interface between silicon and polysilicon can be measured for the first time with the advent of the device of the present invention.

In another embodiment, the same processing was performed on the mirror-finished wafer exactly as described above, but the measurement was performed on a wafer having no backside polysilicon seal alone. The results are shown in the column "No polysilicon backside seal" in Table 1. Looking at the bulk lifetime τ _b , 580μs compared to 1059μs for the polysilicon backside seal wafer
And small. The reason that the bulk lifetime τ _b is small is that it is measured small due to contamination introduced during the oxidation process. On the other hand, 1059 μs of the polysilicon backside seal wafer is an appropriate value in light of the value of the original cut out ingot. Therefore, the polysilicon back seal wafer suffered the same contamination, but recovered to near the original value due to the gettering effect of the polysilicon back seal. According to this embodiment, since the bulk lifetime can be separated and evaluated, the gettering effect of polysilicon can be clarified, and it can be seen that the apparatus of the present invention is effective for process evaluation.

Next, a description will be given of an example of an evaluation apparatus for performing measurement using a difference in conductivity change due to a difference in excitation conditions.

In the embodiment shown in FIG. 4 corresponding to FIG.
The center wavelengths of the excitation light sources 2a and 2b for irradiating the front and back surfaces of the semiconductor wafer 1 are different wavelengths of λ ₁ and λ ₂ (≠ λ ₁ ). That is, the surface of the semiconductor wafer 1 is
is illuminated by the central wavelength lambda ₁ of the excitation light from a, the back surface of the semiconductor wafer 1 is the central wavelength lambda ₂ from the excitation light source 2b
Irradiation by the excitation light. The excitation light sources 2a and 2b are controlled and driven by light source driving circuits 3a and 3b, respectively.

The embodiment shown in FIG. 5 irradiates the surface of the semiconductor wafer 1 with excitation light having different center wavelengths λ ₁ and λ ₂ (≠ λ ₁ ). The embodiment shown in FIG. The rear surface of the semiconductor wafer 1 is irradiated with excitation light having different center wavelengths λ ₁ and λ ₂ (≠ λ ₁ ).

In the embodiment shown in FIG. 7, one surface of the semiconductor wafer 1 is irradiated by one excitation light source 2a having a center wavelength λ ₁ . The front and back reversing mechanism 16 reverses the front and back of the semiconductor wafer 1 so as to excite both surfaces at the same location. The same measurement as described above can be performed by each of the above devices. The same measurement can be performed by inverting the front and back of the semiconductor wafer 1 by the above mechanism and irradiating excitation light having different center wavelengths λ ₁ and λ ₂ (≠ λ ₁ ) as shown in FIGS. Is possible.

The impedance adjusting section 8 of the device of the present invention comprises:
This is a part for adjusting the impedance including the antenna 4 and the semiconductor wafer 1 so as to conform to the measurement conditions. However, the same operation can be realized by changing the oscillation frequency of the electromagnetic wave oscillator 10. FIG. 8 shows an example in which the frequency of the electromagnetic wave oscillator 10 is replaced with a variable frequency oscillator 17 capable of changing the frequency. FIG.
An example in which the circulator 9 and the antenna 4 are connected by a transmission line 18 is shown.

Various forms can be applied to the antenna 4 for irradiating the semiconductor wafer with electromagnetic waves and detecting the impedance. In the apparatus of the present invention, the impedance measuring device is provided around the portion of the wafer excited by the excitation light. The sensitivity is higher when the electromagnetic waves are concentrated. For this reason, an antenna that can concentrate electromagnetic waves in a small area is desirable.

FIG. 10 shows a configuration example of an antenna suitable for the present invention.
Shown in Forming an antenna conductor 4a of a conductor loop (in this example, 1/10 or less) of a size sufficiently smaller than the wavelength of the electromagnetic wave,
The capacitor 20 is connected to the open end of the conductor loop. An LC resonance circuit is formed by the inductance of the antenna conductor 4a and the capacitance of the capacitor 20, and tuning is performed near the oscillation frequency. The capacitor 20 may be of a variable type and may be adjustable. Power is supplied by providing a tap 19 on the antenna conductor 4a, and by adjusting the position of the tap 19, the impedance of the antenna including the semiconductor wafer 1 can be adjusted. With an antenna with such a configuration,
Even though the loop is sufficiently smaller than the wavelength of the electromagnetic wave, the electromagnetic wave can be concentrated, and high-sensitivity impedance measurement can be performed.

Although FIG. 10 shows an example of a circular loop, the loop may have an arbitrary shape such as a square or a pentagon. In addition, a waveguide, a strip line, a coaxial cable, or the like can be used instead of the antenna.

In the embodiment of FIG. 1, when the steady-state impedance is measured without irradiating the excitation light from the excitation light sources 2a-1 and 2a-2, a steady signal proportional to the conductivity of the semiconductor wafer 1 is obtained. Can be On the other hand, the amplitude of the signal due to the change in conductivity upon irradiation with the excitation light, that is, the signal shown in FIGS. 2B and 2C changes depending on the conductivity of the semiconductor wafer 1. Therefore, when the measurement is performed with the intensity of the excitation light kept constant, the amplitude becomes excessive depending on the conductivity of the semiconductor wafer 1 and the detector 11 or the amplifier 12 is saturated, or the amplitude becomes too small. Sufficient detection sensitivity may not be obtained. For this reason, if the steady-state signal is measured immediately before the irradiation measurement by the excitation light, the conductivity of the semiconductor wafer is estimated in advance, and the intensity of the excitation light is controlled according to the estimated value, the amplitude of the change is input. The measurement can be suppressed within an appropriate measurement range by the measurement circuit, that is, the detector 11 and the amplifier 12, and accurate measurement can be performed.

In each of the above embodiments, the radiation of the electromagnetic wave to the semiconductor wafer and the detection of the impedance of the semiconductor wafer are performed by one antenna.
As shown in (1), an antenna 4-1 for radiating electromagnetic waves to the semiconductor wafer 1 and an antenna 4-2 for detecting the impedance of the semiconductor wafer 1 may be separately provided. In the case of the present embodiment, the antenna 4-1 is connected to the circulator 9 and the impedance adjuster 8 by the electromagnetic wave oscillator 10.
-1 is supplied through the circulator 9
Does not need to control the direction of the signal, and has the function of preventing the reflected wave from returning to the electromagnetic wave oscillator 10. Therefore, it is only necessary to have the function of an isolator. Further, the signal from the antenna 4-2 whose impedance has been detected is input to the detector 11 via the impedance adjusting unit 8-2, and subjected to signal processing in the same manner as in the above-described embodiment.

Although an incandescent lamp having a wide wavelength spectrum may be used as the bias light source 5, the heat generated by the evaluation device cannot be ignored. Instead of incandescent lamps, use semiconductor light emitting devices with an appropriate wavelength spectrum,
Further, FIG. 1 shows an example of a light source device (20) in which the device is simplified and maintenance is facilitated by being integrally formed with the excitation light source 2.
It is shown in FIG. That is, the excitation light source 2 for irradiating the excitation light is disposed at the center of the disk 21, and a plurality of bias light sources 5 are provided around the excitation light source 2. When an evaluation device is configured using the light source device 20 having such a structure, the evaluation device is as shown in FIG.
Excitation light and bias light are emitted from the light source device 20 to the front and back surfaces of the semiconductor wafer 1. Therefore, the device is simplified.

FIG. 14 shows the surface recombination speed (FIG. 14 (a)), the bulk lifetime (FIG. 14 (b)), and the back surface recombination speed (FIG. 14 (c)) of the semiconductor wafer separated and measured by the apparatus of the present invention. ) Shows an example of mapping display (or printing) of each of the surface distributions. By comparing and examining these distributions, it is possible to easily identify the contamination source, the degree of damage, and the detection of processing strain.

[0039]

As described above, according to the present invention, it is possible to accurately and clearly separate and evaluate the quality of a semiconductor wafer, which is required to have higher quality in the future, especially the interface and bulk life time near the surface, which are important. Therefore, it is possible to evaluate the vicinity of the surface, the interface, and the bulk, which could not be evaluated until now, and it is possible to perform the evaluation without performing any surface treatment. By rapid evaluation of the manufactured semiconductor wafer, the quality of the subsequent manufacturing process can be determined and improved, which greatly contributes to the improvement of the quality of the semiconductor wafer.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of an evaluation device according to the present invention.

FIG. 2 is a diagram schematically showing a signal processing procedure according to the present invention.

FIG. 3 is a diagram illustrating an example of a measurement signal.

FIG. 4 is a partial configuration diagram showing another embodiment of the evaluation device according to the present invention.

FIG. 5 is a partial configuration diagram showing still another embodiment of the evaluation device according to the present invention.

FIG. 6 is a partial configuration diagram showing a modified example of the device shown in FIG.

FIG. 7 is a partial configuration diagram showing still another embodiment of the evaluation device according to the present invention.

FIG. 8 is a partial configuration diagram showing still another embodiment of the evaluation device according to the present invention.

FIG. 9 is a diagram illustrating a modified example of the impedance adjustment unit.

FIG. 10 is a diagram showing a structural example of an antenna used in the present invention.

FIG. 11 is a configuration diagram showing still another embodiment of the evaluation device according to the present invention.

FIG. 12 is a diagram showing an example of a light source device applicable to the present invention.

13 is a configuration diagram showing an example of an evaluation device using the light source device of FIG.

FIG. 14 is a diagram showing a surface distribution of a front and back surface recombination speed and a bulk lifetime according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor wafer 2 Excitation light source 3 Light source drive circuit 4 Antenna 5 Bias light source 6 Wafer holding mechanism 7 Drive mechanism 8 Impedance adjustment part 9 Circulator 10 Electromagnetic wave oscillator 11 Detector 12 Amplifier 13 A / D converter 14 CPU 15 Printer 16 Front / back inversion mechanism 17 Variable frequency oscillator 18 Transmission line

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-338547 (JP, A) JP-A-8-335617 (JP, A) JP-A-55-67149 (JP, A) JP-A-6-38549 85023 (JP, A) JP-A-57-17142 (JP, A) JP-A-10-125755 (JP, A)

Claims (10)

(57) [Claims] A semiconductor wafer characteristic evaluation apparatus for irradiating a semiconductor wafer with excitation energy and measuring the lifetime of generated carriers to evaluate the quality of the semiconductor wafer. An excitation light source for irradiating light, an antenna for emitting an electromagnetic wave to measure the impedance of the semiconductor wafer, an electromagnetic wave oscillator for supplying an electromagnetic wave to the antenna via a circulator and an impedance adjusting unit, and a signal from the antenna A signal processing circuit that separates and inputs the semiconductor wafer by the circulator, and separates and measures the surface recombination speed and bulk lifetime of the semiconductor wafer, and irradiates one surface of the semiconductor wafer with excitation light.
After measuring, turn the semiconductor wafer over and reverse
An apparatus for evaluating characteristics of a semiconductor wafer, wherein the measurement is performed by irradiating the same portion of the surface . 2. An antenna according to claim 1, wherein said antenna has a wavelength
Conductors of circular or arbitrary shape with sufficiently small dimensions
Form LC resonance circuit with capacitor connected to open end of loop
A tap on the conductor loop, and
2. The half according to claim 1, wherein the power is supplied from a tip.
Evaluation equipment for conductor wafer characteristics . 3. The semiconductor wafer is irradiated with excitation energy.
And measure the lifetime of the generated carrier.
Evaluation of semiconductor wafer characteristics to evaluate conductor wafer quality
In the valuation apparatus, the front and back surfaces of the semiconductor wafer or a piece
An excitation light source for irradiating a surface with excitation light, and the semiconductor wafer
A first antenna that emits an electromagnetic wave on one side of the first antenna;
An electromagnetic wave oscillator for supplying an electromagnetic wave to an antenna of the
A second method for measuring the impedance of the conductor wafer
An antenna and a signal from the second antenna
Input via the dance control unit, the table of the semiconductor wafer
Signal for separating and measuring surface recombination speed and bulk lifetime
And a processing circuit for exciting one side of the semiconductor wafer.
After measuring by irradiating light, the semiconductor wafer is turned upside down.
Reversed by the rotation mechanism, the same part on the opposite surface is the same center
It is characterized by irradiating with excitation light of wavelength
Evaluation device for semiconductor wafer characteristics. 4. The method according to claim 1, wherein said first and second antennas use
Circular or optional, with dimensions sufficiently smaller than the wavelength of the electromagnetic wave
LC with a capacitor connected to the open end of the conductor loop
Form a resonant circuit and tap on the conductor loop
And the power is supplied from the tap.
Item 4. An apparatus for evaluating semiconductor wafer characteristics according to Item 3. 5. The electromagnetic wave oscillator and the first antenna
A circulator or isolator is inserted between
An apparatus for evaluating semiconductor wafer characteristics according to claim 3. 6. The circuit according to claim 1, wherein said signal processing circuit is said circulator.
A detector for detecting these signals, and a signal detected by the detector.
An A / D converter for digitizing a signal;
A CPU that processes and calculates digital signals from the converter
6. The semiconductor wafer according to claim 1, wherein
Sex evaluation device. 7. A system which can vary the frequency of the electromagnetic wave oscillator.
An apparatus for evaluating characteristics of a semiconductor wafer according to claim 1. 8. The method according to claim 8, wherein the semiconductor wafer is provided on both front and back surfaces or one surface.
10. A bias light source for irradiating a bias light.
An apparatus for evaluating semiconductor wafer characteristics according to any one of Items 1 to 5. 9. The pump light source and the bias light source are integrally formed.
9. The apparatus for evaluating semiconductor wafer characteristics according to claim 8, wherein
Place. 10. The surface of each surface of a measured semiconductor wafer.
The surface velocity distribution and the bulk lifetime
It is designed to be displayed separately on the display device
An apparatus for evaluating semiconductor wafer characteristics according to claim 1.
Place.