JPH04179118A - Method and device for improving crystallizability of semiconductor - Google Patents

Abstract

PURPOSE:To enable the inspection and the improvement of the crystallizability to be effected by one device almost simultaneously by a method wherein the crystallizability in the fine region of a semiconductor crystal is evaporated so as to improve the crystallizability in the very fine region. CONSTITUTION:The laser beams 1 are focussed to irradiate a semiconductor specimen 9 so as to evaluate the crystallizability of the semiconductor by the produced Raman spectrum. At this time, the peak position and the half value width of the Raman spectrum of the measured semiconductor are compared with those of a reference control. When said peak position and the half value width are notably slipped from those of the reference control, the laser beam intensity is heightened or the very measured position is laser-annealed using the other prepared annealing laser to improve the crystallizability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for improving the crystallinity of a semiconductor.

[Conventional technology]

Figure 4 is an example of a conventional Raman spectroscopy apparatus shown in "Evaluation of Semiconductors by Laser Raman Spectroscopy" by Takashi Kawato 1), University of Tokyo Press, p. 17. In the figure, 1 is an Ar+ laser, 3 5 is a mirror, 5 is a Raman photodetector, 6 is a spectroscope, 7 is a condensing optical system, and 9 is a sample.

Next, the operation will be explained. The laser beam from Ar+laser l is transmitted to mirror 3. The Raman light is irradiated onto the sample 9 through the condensing optical system 7, separated into spectra by the spectrometer 6, and sent to the Raman photodetector 5.
to obtain a Raman spectrum. The peak position and half-width of the Raman spectrum from a sample change depending on the crystallinity of the sample. If the peak position and half-value width of the Raman spectrum of the crystal are used as a reference, the peak position when the crystallinity is poor will no longer match that of the crystal, and the half-value 1] will become wider. Therefore, the crystallinity of a sample can be determined by comparing the peak position and half-width of the Raman spectrum of the sample with those of the crystal.

As described above, if a defective portion is detected after Raman spectrum measurement, there is no way to anneal only that portion; instead, the entire sample is placed in a separate annealing device and annealed.

[Invention or problem to be solved]

As mentioned above, in the conventional method, evaluation of crystallinity and annealing are completely different processes, so when the defect in crystallinity is in a minute part, the method to improve this is to evaluate the entire sample. Annealing is necessary, and there has never been a process that combines evaluation of crystallinity with annealing of minute parts.

This invention was made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method and device for improving semiconductor crystallinity, which can perform crystallinity inspection and improvement using the same device and at almost the same time. With the goal.

[Means to solve the problem]

The method and device for improving semiconductor crystallinity of the present invention evaluates the crystallinity of a minute region of a semiconductor crystal using laser Raman spectroscopy, etc., and then performs laser annealing on that very minute region in the same device to improve the crystallinity. It is intended to be improved.

[Effect]

The method and device for improving semiconductor crystallinity in this invention include:
The process of evaluating and improving the crystallinity of minute regions can be performed continuously, and only the regions with poor crystallinity can be improved, so there is no need to make the entire product defective due to a defect in a minute region.
Yield can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram of an m apparatus that implements a method for improving semiconductor crystallinity according to an embodiment of the present invention.

In the figure, l is an Ar+ laser, 2 is a variable ND filter, 3 is a mirror, and 4 is a C that controls this system.
PU, 5 is a Raman photodetector, 6 is a spectroscope, 7 is a condensing optical system for condensing laser light, 8 is an XY stage, and 9 is a sample.

Next, a method for improving semiconductor crystallinity according to this embodiment will be explained.

A semiconductor sample is irradiated with a laser beam focused on the order of several micrometers, and the crystallinity of the semiconductor is evaluated from the Raman spectrum obtained. At this time, the Raman spectrum of the crystalline semiconductor serving as a reference is measured in advance and stored in a data file. Next, the Raman spectrum of the sample is compared with the Raman spectrum of this reference to obtain information regarding the crystallinity of the sample. In this embodiment, it is assumed that the crystal is in a polycrystalline state and that this is to be improved.

In a Raman spectrum, the index of crystallinity is a Lorentzian waveform caused by crystal lattice vibrations, and the peak position and half-width of this waveform are used as a guide to judge whether the crystallinity is good or bad. There is.

Therefore, the peak position and half value 1] of the measured Raman spectrum of the semiconductor are compared with those of the reference crystal. If there is a large deviation from that of the reference crystal, increase the laser light intensity or use another annealing laser to anneal the exact location where the crystal was measured. improve.

Next, the method of this embodiment, that is, the operation of the apparatus of this embodiment will be explained in detail with reference to the flowchart of FIG.

In FIG. 2, first, the Raman spectrum of sample 9 is measured. The peak position of this spectrum.

The half value width is determined by the CPU 4 (step 1).

At this time, for example, the peak position and half-value IJ of the Raman spectrum of the reference sample are set to ω3°++, respectively.
Let r'++*r1. Each of those of sample 9 above is ω
s64. If F51, 1ωRcI −ωSan+ l≦n] ・・・■l
T'Rel −r, , l≦M −0m, M
Is it a criterion that is a constant depending on the allowable range of crystallinity? ((Accordingly, determine the crystallinity (Step 2).

If this basis does not conform to I-, move the variable ND filter 2 to make the laser beam of the AI-" laser stronger,
Perform laser annealing (step 3). If it is compatible,
Move the X-Y stage 8 to the next measurement point (
Step 4). In either case, the Raman spectrum is then measured, the same judgment is made, and these are repeated.

Once the measurement points are completed, the operation ends.

Figure 3 is a diagram showing reference Raman spectrum 8 and sample Raman spectrum B when the sample is Si, and as shown in A in the figure, ωRat = 520 C
m-'+ rear = 3. 5 Cm-', the required range m of 6) and F, M is Icm-
', Icm-', it is possible to judge whether the quality of the crystal is good or not, and those that fail this, for example, as shown in B in the figure, ωRam -500cm-', T' Sam =
If it is 5 cm', it is determined that the crystallinity is poor.

These ω□)+T'Rel, m, and M are determined in advance from Raman measurement of a perfect crystal. For example, in the case of GaAs, 6) Ret "290Cm-'+ V Rcl
=5cm-'.

In this way, in this example, the crystallinity in a micro region of a semiconductor can be evaluated by Raman scattering spectroscopy, and as a result of this evaluation,
Microregions determined to have poor crystallinity can be laser annealed immediately.
Since it is possible to improve the crystallinity of a micro region of a semiconductor, it is possible to improve the crystallinity of a micro region of a semiconductor.
Semiconductor devices that are completely defective can be regenerated, which has the effect of improving yield.

In the above embodiment, a variable ND filter 2 is inserted in the laser optical path in order to make the intensity of the Ar+laser I variable, but another laser (for example, YAG or C02 laser) may be provided with an appropriate optical system. The same effect can be obtained by adding it.

Furthermore, although Raman spectra are used to evaluate crystallinity in the above embodiments, photoluminescence may be used instead of Raman spectra.

In this case, since the crystallinity can be judged from the peak position and half value 111 of the photoluminescence spectrum, the judgment criteria based on the equations (1) and (2) above can be used in the same way as above, and the flowchart shown in FIG. 2 can be used. In addition, the measurement system can also change the detection band of the detector, and similar effects can be expected.

〔Effect of the invention〕

As described above, the present invention includes a means for evaluating the crystallinity of a minute region of a semiconductor, and a means for improving the crystallinity in the very minute region whose crystallinity was evaluated by the evaluation means. The process of evaluating and improving the crystallinity of minute regions can be performed continuously, and minute crystallinity improvements can be made for arbitrary regions such as only regions with poor crystallinity. As a result, it is possible to regenerate a semiconductor device that would conventionally be defective as a whole due to a defect in a minute area, and has the effect of improving yield.

[Brief explanation of the drawing]

Figure 1 is a system configuration diagram of a method for improving semiconductor crystallinity according to an embodiment of the present invention, Figure 2 is a flowchart of the system, Figure 3 is a Raman spectrum, and Figure 4 is a configuration diagram of a conventional embodiment. It is. In the figure, l is an Ar+ laser, 2 is a variable ND filter, 3 is a mirror, 4 is a CPU, 5 is a Raman photodetector, 6 is a spectrometer, 7 is a microscope, 8 is an X-Y stage, and 9 is a sample. . Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (4)

[Claims] (1) A semiconductor crystallinity improving device comprising means for evaluating the crystallinity of a minute region of a semiconductor, and means for improving the crystallinity in the very minute region whose crystallinity has been evaluated by the above-mentioned evaluation means. (2) A method for improving semiconductor crystallinity, which includes a step of evaluating the crystallinity of a minute region of a semiconductor, and a step of improving the crystallinity of the very minute region whose crystallinity was evaluated in the above evaluation step. (3) The semiconductor crystallinity improving device according to claim 1, wherein the evaluation method evaluates the crystallinity of the semiconductor by Raman scattering spectroscopy. (4) The semiconductor crystallinity improving apparatus according to claim 1, wherein the evaluation means improves the crystallinity in a micro region of the semiconductor by laser annealing.