JP2000150412A - Method and device for treating semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost, to improve the degree of freedom for adjusting the intensity distribution of light, and to realize optimization of processes for various samples at the time using a semiconductor treating technique for changing the property of a semiconductor by irradiating the semiconductor with light having a periodic intensity distribution. SOLUTION: A light having a periodic intensity distribution is constituted of interference fringes formed by splitting the laser beam from a laser 10 into two split laser beams through a beam splitter 20 and respectively reflecting the split laser beams by first and second mirrors 30 and 40, and then, after deflecting the reflected split laser beam from the mirror 40 from the optical axis of the reflected split laser beam from the mirror 30 by an angle, superposing the former upon the latter so that they may interfere with each other. A thin film semiconductor 61 is crystallized in a large particle diameter by melting the semiconductor 61 in the temperature distribution following the intensity distribution of the interference fringes and cooling the melt. Since no reflection preventing film, etc., is required for the semiconductor 61, the manufacturing cost of the semiconductor 61 is reduced. In addition, the optimization of processes for various samples is realized by improving the degree of freedom for adjusting the intensity distribution of light by adjusting the amplitude ratio between the split laser beams or the length difference between the optical paths of the split laser beams.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor processing method for forming a periodic temperature gradient inside a thin film semiconductor by utilizing the phenomenon of light interference, and more particularly to a method for forming a crystal having a large grain size in a thin film semiconductor. The present invention relates to a semiconductor processing method suitable for application and a processing apparatus for performing the processing.

[0002]

2. Description of the Related Art As a method of irradiating a thin film semiconductor with a laser beam to form a spatial temperature gradient therein and forming a crystal having a large grain size by using the temperature gradient, a first prior art is disclosed in the United States. It is disclosed in Japanese Patent No. 4,523,962. In this semiconductor processing method, as schematically shown in FIG. 8, a thin film semiconductor 102 such as amorphous silicon (a-Si) or polysilicon (poly-Si) is formed on a surface of a substrate 101 such as glass by a thin film such as CVD. It is formed thin by the process. Next, a thin dielectric film such as silicon oxide (SiO ₂ ) is formed on the thin film semiconductor 102 by a thin film forming process such as CVD, and then patterned into a grid by a photolithography process. The remaining dielectric film functions as an anti-reflection film 103 for the laser beam 100. When scanning is performed while continuously irradiating the laser beam 100 on this structure, the laser beam 100 is almost completely absorbed on the surface of the thin-film semiconductor 102 and is radiated to the same place for a short time, so that the temperature of the substrate 101 rises. Is small. At the moment when the laser light 100 is irradiated, the portion of the thin film semiconductor 102 under the anti-reflection film 103 absorbs the laser light 100 well by the anti-reflection effect of the anti-reflection film 103 and becomes high temperature. Since the laser light 100 is reflected, the energy of the thin-film semiconductor 102 absorbing the laser light 100 is small, and the temperature is unlikely to rise. As a result, the thin film semiconductor 102 is
Only the lower part of 3 is selectively hot. Anti-reflection film 103
Are formed in a grid shape, a periodic temperature distribution corresponding to this is formed inside the thin film semiconductor 102.

Next, when the laser beam 100 is scanned and the supply of energy to this structure is interrupted, the thin film semiconductor 1 is scanned.
The initial temperature distribution changes due to heat radiation from the high-temperature part 02 to the surroundings. Here, as the boundary between the high-temperature portion and the low-temperature portion of the thin film semiconductor 102 moves, the crystal grows in the horizontal direction. Ends. By adjusting the width of the antireflection film 103, a crystal larger than the film thickness can be obtained. The place where such a large crystal can be formed is under the antireflection film, and can be controlled with a high degree of freedom by using a photolithography process. Therefore, when a semiconductor device such as a thin film transistor is manufactured by this semiconductor processing method, a device having good characteristics and excellent uniformity can be obtained.

[0004] In the above, a method of scanning while continuously irradiating laser light has been described as an example. However, it is possible to obtain similar results by irradiating pulse light from an excimer laser onto a similar structure. Paper (HJ Kim and James S. Im,
“New excimer-laser-crystallization method for pro
reducing large-grained and grain boundary-location-c
ontrolled Si films for thin film transistors, ”A
ppl. Phys. Lett. 68 (11), 11 Mar. 1996, pp. 1513-15
15.)

A second prior art of a conventional semiconductor processing method using a temperature gradient by laser light irradiation is disclosed in a paper (James S. Im, Robert S. Sposili, and MA Crowde).
r, “Single-crystal Si films for thin-film transist
or devices, ”Appl. Phys. Lett. 70 (25), 23 Jun. 19
97, pp. 3434-3436.). FIG. 9 shows an outline of this method. In this method, a laser beam 100 is transmitted through a slit 104 having a periodic opening, and an image is formed on a surface of a thin film semiconductor 102 by an imaging optical system 105. In this conventional technique, the laser light is pulse light from an excimer laser. Since the spatial distribution of the energy of the light transmitted through the slit 104 is steep, the inside of the semiconductor 102 immediately after the irradiation has a steep temperature distribution close to a rectangle. The process in which the crystal grows along with the heat radiation to the substrate is the same as in the first prior art. Here, the region where the crystal grows is a narrow region corresponding to the image of the slit. However, when the substrate 101 is moved by half the width of this region and then irradiated with the second laser light, half of the region where the crystal has grown by the first irradiation is also melted, and the remaining unmelted part is melted. The crystal grows over the entire region melted by the second laser light irradiation based on the crystal. By repeating this process, a crystal region can be obtained over a large area.

Further, a third prior art of a conventional semiconductor processing method utilizing a temperature gradient caused by laser beam irradiation is disclosed in Japanese Patent Application Laid-Open No. 6-140323. This is because the light from the excimer laser is diffracted by the diffraction grating 11 as shown in FIG.
1 changes two concentric waves, and guides the interference light to the thin-film semiconductor to form a temperature distribution as shown in FIG. This method of forming interference fringes is generally known as Young's double slit experiment. Japanese Patent Application Laid-Open No. 57-99734 discloses a method for growing a crystal by forming a periodic temperature distribution inside a semiconductor by using light interference and standing waves.
The method of obtaining the interference fringes is the same as that of Young's experiment shown in FIG. 10, and is the same in this respect.

[0007]

As described above, the technique of generating a periodic temperature distribution in a semiconductor and obtaining a crystal having a large grain size by using this temperature distribution is described in the first to third embodiments. Has already been realized as shown in the prior art. However, in the above-described related art, the following problem occurs in connection with a method for obtaining a periodic temperature distribution.
First, in the first prior art, a process of forming and patterning a dielectric film as an anti-reflection film is required, which causes an increase in manufacturing cost. Also, since the position of the dielectric film once formed is fixed, as in the second prior art,
By moving the substrate and repeating the second and third crystal growth steps, a large area crystal cannot be obtained.

In the second prior art, a moving accuracy of an optical system and a substrate for forming an image of a slit on the surface of a thin film semiconductor and a sufficient depth of focus of the optical system are required. Since a large-area substrate is warped, it is difficult to control the crystal growth over the entire surface of the substrate unless the movement accuracy of the substrate and the depth of focus of the optical system are sufficient. In order to optimize the process of growing a crystal using a temperature gradient for various thicknesses and types of thin film semiconductors, it is desirable that the initial temperature distribution can be adjusted as freely as possible. The initial temperature distribution obtained is only a steep distribution close to a rectangle, and the degree of freedom in adjusting the temperature distribution is significantly limited.

In the third prior art, the intensity of the interference fringes is maximum at the position of the substrate corresponding to the center of the two slits,
Since the intensity of the adjacent interference fringes is lower than this, the degree of freedom for controlling the intensity distribution of the interference fringes is low as in the second related art, and the process optimization for various samples can be performed. Have difficulty. Therefore, if the intensity of the laser beam is adjusted so that crystallization is optimized at the center interference fringe, it will not be optimum for other interference fringes, and the area that can be crystallized by one irradiation will be small. Further, since it is necessary to provide a slit near the semiconductor thin film, there is a problem that atoms vaporized by laser light irradiation contaminate the slit and the intensity distribution changes with time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor processing method and a semiconductor processing apparatus which are low in manufacturing cost, excellent in controllability of a temperature gradient inside a semiconductor, and capable of crystallizing a large grain size over a large area. It is.

[0011]

According to the present invention, there is provided a semiconductor processing method for irradiating a surface of a semiconductor with light having a periodic intensity distribution to change properties of the semiconductor. The distribution is characterized by interference fringes formed by the respective waves of the amplitude-divided laser light interfering with each other. Here, at least a part of the energy of the interference fringes is large enough to melt the semiconductor, and a crystal formed when at least a part of the semiconductor is periodically melted and cooled. The width of the region is equal to or less than the interval between the interference fringes.

Further, in the semiconductor processing method of the present invention, the laser light may be applied to the same location of the semiconductor once or more times in a pulsed manner, or to the same location of the semiconductor once or multiple times. Then, the step of re-irradiating after changing the relative position of the interference fringe and the semiconductor is repeated. At this time, 2
The position of the interference fringes is controlled such that a region of the semiconductor that is melted by the first irradiation of the laser light overlaps a region of the semiconductor that is melted by the first irradiation of the laser light. Alternatively, the semiconductor processing method of the present invention is characterized in that the laser beam is continuously applied to the semiconductor while the positions of the semiconductor and the interference fringes are relatively continuously changed.

The semiconductor processing apparatus according to the present invention comprises a laser beam generating means, a dividing means for dividing the amplitude of the laser light into two, and an interference fringe generated by superposing and interfering each of the divided laser lights. And a means for changing the optical axis angle of at least one of the laser beams with respect to the other. Here, the dividing means and the superimposing means are constituted by one or a plurality of exchangeable beam splitters having different amplitude division ratios. In addition, there are provided first and second reflecting means for respectively reflecting the amplitude-divided laser beams with respect to the superimposing means, and between the first and second reflecting means and the superimposing means. Means for changing the optical path length of the optical disk. Further, the semiconductor processing apparatus according to the present invention is characterized in that the semiconductor processing apparatus includes means for irradiating the semiconductor with a uniform intensity distribution of the second laser light in synchronization with the interference fringes.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of a semiconductor processing apparatus used in the semiconductor processing method of the present invention. The semiconductor processing apparatus includes a laser 10 that emits a laser beam that is coherent light, and a beam splitter 20 that divides the laser beam emitted by the laser 10 into two, that is, divides the amplitude of the laser beam into two. First to reflect the split laser light respectively
, A second mirror 40, and an actuator 50 that supports the second mirror 40 and can move the second mirror 40 along the incident optical axis. Here, the beam splitter 20 splits the laser light as described above, while superimposing each laser light reflected by the first and second mirrors 30 and 40, and superimposing both laser lights by the superposition. It also has the function of causing interference. That is, the beam splitter 20, the first mirror 30, and the second mirror 40 have basically the same configuration as an interferometer known as a Michelson interferometer. Then, the interference fringes 70 obtained by this processing apparatus are irradiated onto the substrate 60 on which the amorphous or polycrystalline thin film semiconductor 61 is formed as a processing target.

In the configuration of the present invention, a laser 10 having an output energy sufficient to melt a thin film semiconductor is used. For example, XeCl, KrF, Ar
An excimer laser such as F, or a continuously oscillating Ar laser is used. Further, the beam splitter 20 does not necessarily have a configuration in which the ratio of the amplitudes of the laser beams to be split is always 1: 1, but may use a beam splitter that can asymmetrically split the beam, for example, 10: 1. Further, the actuator 50
Can move the second mirror 40 by a small distance in the direction of the optical axis and slightly change the angle of reflection of the reflected laser light by a small angle ε, as described above. It is configured as a reflecting mirror that is inclined with respect to a plane perpendicular to. If this actuator is configured to use, for example, a piezo element, it can be quickly moved by a computer control over a minute distance of about the wavelength of light.

Next, a semiconductor processing method using the semiconductor processing apparatus of the first embodiment will be described. The laser light emitted from the laser 10 is applied to a beam splitter 20.
Divides the amplitude into two laser beams. The split laser beams are reflected by the first mirror 30 and the second mirror 40, respectively, are again incident on the beam splitter 20, where they are superposed and interfere with each other. Here, if the optical path lengths of the two laser beams reflected by the first mirror 30 and the second mirror 40 are made equal, the second mirror 40 is slightly inclined, so that the surface of the substrate 60 is evenly spaced. Interference fringes are generated.
This is equal thickness interference by non-parallel thin plates and is known as Fizeau interference fringes. Here, assuming that the wavelength of the light is λ, the refractive index of the atmosphere is n, and the inclination angle of the second mirror 40 is ε, the pitch size of the interference fringes is λ / nε and is a linear stripe. . The position of the interference fringes on the substrate 60 is determined by the beam splitter 20 and the second mirror 4.
Since it depends on the optical path length of 0, that is, the position where the reflected light from the second mirror 40 is incident on the beam splitter 20, it is possible to freely change the position by adjusting the position of the second mirror 40 by the actuator 50. it can.

The light intensity distribution on the surface of the substrate 60 also depends on the ratio of the amplitude division of the two laser beams split by the beam splitter 20. For example, when the amplitude ratio of the laser beam to be separated and split into the first mirror 30 and the second mirror 40 is A1: A2 and the amplitude ratio is 1: 1, the intensity shown in FIG. A distribution is obtained. When the amplitude ratio is 1:10, the intensity distribution is as shown in FIG. Here, ε = 0.01 and n = 1.

It is also possible to utilize the fact that the coherence of the laser beam is reduced when the optical path length is increased, and the contrast of the interference fringes is reduced. For example, the actuator 50
As a result, the contrast of the interference fringes decreases as the second mirror 40 is moved away from the beam splitter 20, and FIG.
The intensity distribution as shown in FIG.

Next, the semiconductor processing method of the present invention utilizing the interference fringes generated by the processing apparatus of FIG. 1 will be described with reference to FIG. In the first processing method, as shown in FIG. 3B, the interference fringes adjusted to the intensity distribution as shown in FIG.
The laser beam is applied to the substrate 60 only once in a pulsed manner, and the pitch of the interference fringes is equal to the crystal growth distance. When the interference fringes irradiate the surface of the thin film semiconductor 61 on the substrate 60, a temperature gradient corresponding to the intensity distribution of the interference fringes is generated inside the thin film semiconductor 61 as shown in FIG. That is, a portion where the intensity of the interference fringe is high is set to a higher temperature than a portion where the interference fringe is low. Here, by appropriately setting the intensity distribution of the interference fringes by adjusting the amplitude ratio and the like in the beam splitter 20, the entire area of the thin film semiconductor 61 may be melted, or the thin film semiconductor 61 may be melted at a high temperature and melted at a low temperature. The intensity distribution of the interference fringes may be set so as not to melt in the portion. Then, when the thin film semiconductor 61 is cooled after the irradiation of the interference fringes, as shown in FIG. 3D, in the process, crystals grow in a direction perpendicular to the film thickness of the thin film semiconductor 61 (direction horizontal to the substrate). It reaches a size corresponding to the pitch of the interference fringes. If a part of the low-temperature part does not melt, this part remains without being crystallized. Note that FIG.
Non-melted region 61b, crystal region 61c, boundary 6 of crystal region
1d respectively. This makes it possible to increase the grain size of the thin film semiconductor 61, which is the object of the present invention.

As described above, in the first processing method using the processing apparatus of the first embodiment, since the interference phenomenon of laser light is used, the conventionally required formation and patterning of a dielectric thin film are required. No process is required, the number of processing steps is small, and mass productivity is excellent. Further, since the intensity distribution of the interference fringes is adjusted by controlling the amplitude ratio in the beam splitter or controlling the optical path length, the degree of freedom in controlling the temperature distribution in the semiconductor thin film increases. In other words, the process of melting the thin-film semiconductor by absorbing the energy of the laser light, and crystallizing with cooling by heat radiation, includes the thickness of the thin-film semiconductor, the material existing under the thin-film semiconductor, the atmosphere above the thin-film semiconductor, For example, there are structural factors such as gas types such as nitrogen, argon, and vacuum, and temporal factors such as a pulse width and a pulse shape when the laser light is pulsed. It is a factor that affects the temperature distribution. Many of these can be controlled externally, but their control range is limited by the capabilities of the device and physical limitations. In this regard, in the present embodiment, the structural factors,
It is possible to flexibly respond to various constraints of the time factor. Further, in this embodiment, since non-localized interference fringes are used, even when the size of the substrate 60 is large and warpage or the like occurs and the distance to the optical system depends on the place, a clear interference fringe can be obtained on the substrate. And can easily form crystals on a large-area substrate, and is excellent in mass productivity. Further, since nothing is disposed near the substrate 60, the possibility of contamination of the device by a gaseous object generated due to the absorption of the laser beam into the thin film semiconductor 61 is reduced, and the device is maintained for a long time. Crystal formation can be continued without maintenance, and mass production is excellent.

Next, a second processing method according to the present invention will be described with reference to FIG. In this second semiconductor processing method, the laser light is pulsed, and first, as shown in FIG. 4A, the same location is irradiated once or plural times to grow a crystal. Next, as shown in FIG. 4B, the position of the interference fringes is changed by slightly moving the second mirror 40 by the actuator 50. Thereafter, the process of crystal growth by laser irradiation is repeated. At this time, the first process and 2
In the third process, the positions of the interference fringes are controlled so that the fused portions of the semiconductors overlap each other. FIG. 5 is a diagram showing the intensity distribution of interference fringes in the first irradiation and the second irradiation. The above irradiation is repeated up to a distance corresponding to one cycle of the interference fringe as shown in FIG. Then, by stopping the irradiation of the interference fringes, it is possible to increase the grain size of the thin film semiconductor 61 in the same manner as in the first processing method.

In the second processing method, the same effect as in the first processing method can be obtained. In addition, since the position of the interference fringes on the thin film semiconductor 61 is controlled by changing the optical path length by the second mirror 40, the movement of the interference fringes is easy, and the processing apparatus is small and can be installed easily. It will be advantageous.
Incidentally, in the prior art shown in FIG. 9, it is necessary to control the relative position between the imaging optical system and the substrate with an accuracy of the order of 1 μm, which requires a large-scale mechanism.

Further, as the third processing method in the present invention, a method of continuously changing the position of the interference fringe during one laser irradiation can be adopted. In the third semiconductor processing method, a laser capable of continuous irradiation such as an Ar laser is employed. When irradiating the laser beam with a constant intensity, the second mirror 40 is moved to the actuator 50.
Reciprocates with a constant amplitude around a certain reference position. As a result, the position of the interference fringes on the thin film semiconductor 61 changes continuously. If the moving distance of the second mirror 40 is set to a distance corresponding to one cycle of the interference fringe, the thin film semiconductor can be crystallized on the entire surface of the thin film semiconductor 61 as in the second processing method. In the third processing method, the same effects as those in the first and second processing methods can be obtained.

Here, another configuration example of the semiconductor processing apparatus for adjusting the intensity distribution of interference fringes will be described. In the second processing apparatus shown in FIG. 6, a second beam splitter 21 is provided on the optical path of the laser 10 and the beam splitter 20, and a third mirror 41 for reflecting the light split by the second beam splitter 21 is provided. A fourth mirror 42 is provided. And
The laser beam reflected by the fourth mirror 42 is transmitted to the thin film semiconductor 6
1 is irradiated. In this configuration, the second
Beam splitter 21, third mirror 41, fourth mirror 42
The optical path length of the laser light by the first and second mirrors 30,
The light passing through the third and fourth mirrors 41 and 42 does not interfere with the light passing through the first and second mirrors 30 and 40 because the light passing through the third and fourth mirrors 41 and 42 is significantly different from the light path length that generates the interference fringes due to the light reflected by the first and second mirrors 40 and 40. Absent. Therefore, the intensity distribution of the interference fringes 71 in the thin-film semiconductor 61 is obtained by superimposing uniform intensity on the intensity distribution of the interference fringes. Of course, a configuration may be employed in which the second beam splitter 21, the third mirror 41, and the fourth mirror 42 are used instead of the laser 10 to irradiate in synchronization with each other using a second laser independent of the laser 10.

FIG. 7 shows a third processing apparatus as a configuration example for moving the interference fringes. In this processing apparatus, the position of the interference fringe is controlled by controlling the optical path length using objects having different refractive indexes. That is, for example, a stepped transmission plate 80 made of a transparent material having a different refractive index from air, such as glass, is arranged on the optical path of one of the lights split by the beam splitter 20. The stepped transmission plate 80 can be moved in a direction orthogonal to the optical path by a second actuator 51 as an optical path difference conversion means, and a portion having a different thickness of the stepped transmission plate 80 is selected on the optical path. It is constituted so that it may be located. For this reason, the thickness of the stepped transmission plate 80 on the optical path is changed, and the optical path length is changed according to the distance that the light passes through the stepped transmission plate 80, and the light path is formed on the thin film reaction body 61 accordingly. The position of the interference fringe 70 to be performed can be controlled.

[0026]

As described above, according to the present invention, the following effects can be obtained. In the present invention, since the interference phenomenon of the laser beam divided by amplitude is used as a means for generating a temperature gradient inside the semiconductor, the steps of forming and patterning a dielectric thin film as an antireflection film on the thin film semiconductor are unnecessary. There is an effect that the number of processing steps is small and mass productivity is excellent. Further, in the present invention, as means for controlling the intensity distribution of the interference fringes, a method of controlling the amplitude division ratio in the beam splitter, a method of changing the optical path length, and a third light different from the two interfering lights are used. The advantage of using the irradiation method is that the degree of freedom in controlling the temperature distribution in the semiconductor thin film is increased, and it is possible to flexibly cope with various restrictions such as structural factors and time factors during crystallization. There is. Further, in the present invention, the position of the interference fringes is controlled by changing the optical path length by means such as movement of a mirror or insertion of a material having a different refractive index into the optical path. This is advantageous for installation.

Furthermore, since the non-localized interference fringes are used in the crystal forming method of the present invention, even if the substrate is enlarged and warped or the like and the distance from the optical system depends on the place, the clear interference fringes are formed on the substrate. Can be obtained. Therefore, there is an effect that crystals can be easily formed on a large-area substrate, and mass productivity is excellent. In addition, since nothing is disposed near the substrate, the possibility of contamination of the device by a gaseous object generated due to the absorption of laser light to the substrate is reduced, and the device is maintained for a long time. Crystal formation can be continued without causing an effect of excellent mass productivity.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first processing apparatus of a semiconductor processing apparatus of the present invention.

FIG. 2 is a diagram showing an intensity distribution of interference fringes in the semiconductor processing apparatus of the present invention.

FIG. 3 is a diagram for explaining a first processing method of the present invention.

FIG. 4 is a diagram for explaining a second processing method of the present invention.

FIG. 5 is a diagram showing an irradiation intensity distribution of interference fringes in a second processing method.

FIG. 6 is a configuration diagram of a second processing apparatus of the semiconductor processing apparatus of the present invention.

FIG. 7 is a configuration diagram of a third processing apparatus of the semiconductor processing apparatus of the present invention.

FIG. 8 is an explanatory diagram of a semiconductor processing method according to a first conventional technique.

FIG. 9 is an explanatory diagram of a semiconductor processing method according to a second conventional technique.

FIG. 10 is an explanatory diagram of a semiconductor processing method according to a third conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Laser 20 Beam splitter 21 2nd beam splitter 30 1st mirror 40 2nd mirror 41 3rd mirror 42 4th mirror 50 Actuator 51 2nd actuator 60 Substrate 61 Thin film semiconductor 70, 71 Interference fringe 80 Stairs Transmission plate 100 laser light 101 substrate 102 thin film semiconductor 103 antireflection film 104 slit 105 imaging optical system 111 slit

Claims (11)

[Claims] 1. A semiconductor processing method for irradiating a surface of a semiconductor with light having a periodic intensity distribution to change a property of the semiconductor, wherein the light having the periodic intensity distribution is an amplitude-divided laser light. A semiconductor processing method, wherein the waves are interference fringes formed by interfering with each other. 2. The semiconductor processing method according to claim 1, wherein the energy of at least a part of the interference fringes is large enough to melt the semiconductor. 3. The width of a crystal region formed when at least a part of the semiconductor is periodically melted and cooled,
3. The semiconductor processing method according to claim 2, wherein the distance is equal to or less than the interval between the interference fringes. 4. The semiconductor processing method according to claim 1, wherein the laser beam is applied to the same location of the semiconductor at least once in a pulsed manner. 5. The pulsed laser beam is radiated to the same location of the semiconductor at least once in a pulsed form, and then the relative position between the interference fringe and the semiconductor is changed. 4. The semiconductor processing method according to claim 1, wherein the step of irradiating light is repeated. 6. The position of the interference fringe is controlled such that a region of the semiconductor that is melted by the second irradiation of the laser light overlaps with a region of the semiconductor that is melted by the first irradiation of the laser light. 6. The semiconductor processing method according to claim 5, wherein: 7. The semiconductor device according to claim 1, wherein the laser beam is continuously applied to the semiconductor while the positions of the semiconductor and the interference fringes are relatively continuously changed. The semiconductor processing method according to the above. 8. A laser beam generating unit, a unit for amplitude-dividing the laser beam into two laser beams, and superimposing and interfering each of the laser beams after the amplitude division to form an interference fringe generated by the interference. Superimposing means for irradiating the semiconductor;
Means for changing the angle of at least one of the laser beams superimposed on the other with respect to the other optical axis. 9. The apparatus according to claim 9, wherein said amplitude dividing means and said superimposing means are one of:
9. The semiconductor processing apparatus according to claim 8, wherein one or a plurality of interchangeable beam splitters having different numbers or amplitude division ratios are provided. 10. A first and a second reflecting means for respectively reflecting the amplitude-divided laser beams to the superimposing means, wherein at least one of the first and the second reflecting means and the superimposing means are provided. 10. The semiconductor processing apparatus according to claim 8, further comprising means for changing an optical path length between the semiconductor processing apparatus and the semiconductor processing apparatus. 11. The semiconductor according to claim 8, further comprising: means for irradiating the semiconductor with a uniform intensity distribution of the second laser light in synchronization with the interference fringes. Processing equipment.