JP3435247B2 - Laser light irradiation apparatus and laser light irradiation method - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates relates to a semiconductor manufacturing device, in particular, by irradiating a laser beam on the semiconductor substrate, the laser beam irradiation apparatus and performs various processes using a high energy laser light has The present invention relates to a laser light irradiation method .

[0002]

2. Description of the Related Art As one of semiconductor manufacturing processes, there is a process of irradiating a metal for wiring formed on a semiconductor substrate with a laser beam to melt and reflow the metal so that the molten metal is embedded in a fine wiring hole. is there.

In recent years, in order to improve the degree of integration of LSIs, the wiring width has been reduced, and the number of layers and wiring holes have been reduced. The miniaturization of wiring widths and wiring holes depends on lithographic and etching technologies, and resolutions on the order of submicrons have come to be obtained.

The wiring hole has a role of electrically connecting the layers, and greatly affects the reliability of electrical operation. As the circuit becomes finer, it has become difficult to fill the wiring holes with the wiring metal by the conventional sputtering method. For this reason, not only is the electrical reliability of the wiring impaired, but it has also been an obstacle to multilayering.

Therefore, novel manufacturing methods such as a high temperature sputtering method, a CVD method, and a high temperature reflow method have been proposed. In these manufacturing methods, the wiring holes are filled with a metal, and at the same time, the wiring layer in the hole portions is flattened to facilitate the multilayer structure.

For the same purpose, David B. Tuckerman et al. Also announced a technique of forming a metal wiring layer on the entire surface of a semiconductor substrate by a sputtering method, and then irradiating a laser beam to melt and reflow the wiring to fill the wiring hole. Was done. In this case, since the wiring layer is only melted instantaneously, there is an advantage that the lower layer is not heated and the film quality is improved.

FIG. 8 is a schematic configuration diagram of a laser light illuminating device having the above-mentioned wiring melting / reflowing function. The laser light 2 output from the laser light source 1 is reflected by the mirror 3 and is incident on the imaging lens 4. The semiconductor substrate 8 is provided near the bottom surface of the container 7 having the window 6 in which the transparent glass 5 is fitted on the top surface.
Is placed on an XY table (not shown). Container 7
An exhaust port 9 communicating with an exhaust pump (not shown) for maintaining the inside of the container 7 in a vacuum state below atmospheric pressure is formed at a position below a side wall of the container. The imaging lens 4 images the incident laser beam 2 on the semiconductor substrate 8 in the container 7 through the window 5. Then, the XY table (not shown) is moved within a horizontal plane to scan the semiconductor substrate 8 with the laser light 2.

[0008]

However, the laser beam irradiation apparatus shown in FIG. 8 still has the following problems to be solved. As described above, when the wiring layer formed on the semiconductor substrate 8 is melted / reloaded by the laser light 2, the periphery of the semiconductor substrate 8 is, for example, in order to prevent oxidation of the metal film for wiring and contamination. The vacuum state is maintained below atmospheric pressure of about 10 ⁻⁵ Pa. At this time, the saturated vapor pressure of the molten metal is 1 for aluminum Al.
0 ^-6 Pa (660 ° C), copper Cu 1 Pa (1080 ° C)
C).

In the case of Al, vapor is less likely to be generated even at a reduced pressure ratio of 10 ^-5 Pa, but in Cu, vapor is actively generated. Therefore, as shown in FIG.
The molten metal vapor 10 generated at the time of irradiation with respect to the glass adheres to the glass 5 fitted in the window 6 of the container 7. The deposited metal increases in proportion to the number of processed semiconductor substrates 8 and forms a thick film layer. As a result, the transmittance of the laser beam 2 with respect to the glass 5 is reduced, the energy of the laser beam 2 reaching the semiconductor substrate 8 is reduced, the melting of the metal film is insufficient, and the imperfect filling of the fine wiring hole occurs, and the laser beam This will lead to a decrease in the performance of the entire irradiation device.

Further, when the laser light 2 irradiates a certain area or more on the semiconductor substrate 8, as shown in FIG. 9, when the spot 11 of the laser light 2 on the semiconductor substrate 8 is rectangular, it is not irradiated. The irradiation positions of the spots 11 are sequentially moved so as to overlap each other in a minute area so that no portion is generated.

Therefore, when irradiating the area 12 having the shape shown in FIG. 9, the portion 1 in which the laser beam 2 is irradiated once is used.
In addition to 2a, there are two portions 12b, three portions 12c, and four portions 12d.

If the number of times of irradiation is different in the same region 12, the degree of melting of the metal film for wiring and the degree of filling of the fine wiring holes will vary, which will cause quality defects. In order to eliminate such an inconvenience, the energy in one irradiation is reduced and the irradiation frequency for irradiating the same position is set to, for example, 2
Set to 0 etc. In this case, the spots 11 are irradiated in order while shifting the spot 11 by a minute distance.

However, also in this case, as shown in FIG. 10, when the irradiation area extends over two rows or more of spots 11, as in the case of FIG.
2d and a portion which is doubled forty times are generated.

In order to eliminate such a situation, FIG.
As shown in FIG. 1, if the shape of the spot 11a is set to be an elongated shape having a length equal to or more than the entire width of the irradiation area 12,
All the irradiation is completed by one scan, and the same irradiation number is obtained over the entire area 12.

However, in the case of a long and large spot 11a as shown in the figure, it is difficult to maintain a uniform light quantity at each position within the spot 11a, and even if it is possible, it is very expensive. Since it is necessary to use a different optical member, the manufacturing cost increases significantly.

The present invention has been made in view of the above circumstances, and it is possible to prevent molten metal vapor from adhering to the window of the container into which the laser light is incident, and still have a small spot shape. An object of the present invention is to provide a laser light irradiation device and a laser light irradiation method capable of uniformly irradiating the entire irradiation region of a semiconductor substrate.

[0017]

The invention according to claim 1 is a laser
The light source and the laser light emitted from this laser light source
From the shooting kaleidoscope and this kaleidoscope
An imaging lens for imaging the emitted laser light,
Parts can be maintained in a vacuum state below atmospheric pressure, and
XY table for placing the substrate and laser light are transmitted
And a container with a window in which glass for fitting is inserted,
Arranged corresponding to each converging spot of laser light by the lens
A shield having a plurality of through holes formed therein.
The light irradiating device, the focal length of the imaging lens is F,
B ₁ is the distance between the image lens position and the focused spot position
The distance between the lens position and the entrance surface of the kaleidoscope
If B ₂ , then 1 / F = 1 / B ₁ + 1 / B ₂ is satisfied
And the image of the exit surface of the kaleidoscope is the semiconductor substrate.
It is configured to be imaged on.

A second aspect of the present invention relates to the above-mentioned invention.
In the laser light irradiation device, the laser emitted from the laser light source
The incident lens that collects the laser light on the incident surface of the kaleidoscope
It is equipped with

Further, the invention of claim 3 is the above-mentioned invention.
In the laser light irradiation device of
The spot shape of the laser light output from the light source is a quadrangle
Regulated and the XY table was irradiated onto the semiconductor substrate
Laser light with a quadrilateral spot shape is
Scanning is done in the direction of the square line.

Further, the invention of claim 4 is the above-mentioned invention.
In the laser light irradiation device of
The first chamber that contacts the transparent plate and the first substrate that houses the semiconductor substrate
It is divided into two rooms and the inert gas is introduced into the first room.
Turn on and keep the second room below atmospheric pressure.

According to a fifth aspect of the invention, laser light is applied to the semiconductor substrate.
This is a laser light irradiation method for irradiation. And the specified
The laser beam in the shape of a dot on the semiconductor substrate
Irradiate in order while moving a minute distance toward one line
The outward process for ending the scanning and the second process orthogonal to the first direction
The irradiation position of the laser beam in the direction of
A shift step of shifting so that the shapes partially overlap,
A laser beam with a predetermined spot shape is emitted in the opposite direction to the first direction.
Irradiate in order while moving a minute distance toward one line
A return pass process for ending scanning, and a forward pass process and a return pass process
The number of irradiations with and is set to the position in the first direction.
Irrespective of the same irradiation frequency.

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

According to the first aspect of the present invention, by using the kaleidoscope , the light intensity of the laser light output from the laser light source in a wide spot plane is controlled to be substantially constant. Therefore, even if the the even multiple holes at the focal position of the imaging lens provided with drilled shielding plate, it is possible to scan a large number of laser light on the semiconductor substrate at the same time, it improves the irradiation work efficiency.

According to the third aspect of the present invention, the spot shape of the laser light is a quadrilateral with a kaleidoscope , and the laser light is scanned in the diagonal direction of the quadrangle with an XY table. Therefore,
Laser irradiation can be performed uniformly and efficiently.

According to the fourth aspect of the invention, the container is placed above and below the container.
It is divided into steps and a shielding plate is provided at the center of
The inert gas supplied to this chamber flows into the lower second chamber through the laser beam passage portion of the shielding plate.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a laser light irradiation apparatus of an embodiment, and FIG. 2 is an optical system diagram.

As shown in FIGS. 1 and 2, the laser light source 21
The laser light 22 which is repeatedly output in a pulse shape at a constant period (frequency f) is reflected by a mirror 23 and a shaping mask 24.
And enters the imaging lens 25. The shaping mask 24 shapes the spot shape orthogonal to the optical axis of the laser light 22 into a square (quadrangle).

A bottom 26b of a substantially box-shaped container 26 having a window 28 in which a transparent glass 27 is fitted on the top 26a.
An XY table 29 is installed in. The transparent glass 27 does not necessarily have to be fitted into the window 28, and may be provided apart from the window 28, for example. On the upper surface of the XY table 29, a semiconductor substrate 30 which is an irradiation target of the laser light 22 is placed. An exhaust port 31 communicating with an exhaust pump (not shown) for maintaining the inside of the container 26 in a vacuum state below atmospheric pressure at a position below the side surface 26c of the container 26.
Are formed.

The image forming lens 25 forms an image of the incident laser beam 22 on the semiconductor substrate 30 in the container 26 through the window 28. As shown in FIG. 2, a shielding plate 32 is arranged at the focal position (focal length F) of the imaging lens 25. A circular through hole 32a for allowing the laser beam 22 to pass therethrough is formed at the center of the shield plate 32 on the optical axis. Therefore, the laser light 22 is once condensed by the imaging lens 25 at the position of the shield plate 32 (focal position), passes through this focal position, and is imaged on the semiconductor substrate 30. The spot shape of the laser beam 22 imaged on the semiconductor substrate 30 is a square inverted shape of the mask 24.

The through hole 32a does not necessarily have to be bored, and the manufacturing method thereof does not matter as long as it is provided. The shield plate 32 is provided to capture the molten metal vapor 33 emitted by the wiring metal formed on the semiconductor substrate 30 due to the irradiation of the laser light 22, for example. In order to efficiently capture the molten metal vapor 33 and prevent the molten metal vapor 33 once captured from peeling off and falling onto the semiconductor substrate 30, the molten metal vapor 3
The lower surface 32b with which 3 abuts is finished to have a roughness of 10 microns or less.

Then, by moving the XY table 29 within a horizontal plane, the laser beam 22 is directed to the semiconductor substrate 30.
Scan above. In the laser irradiation device configured as described above, the laser light 22 output from the laser light source 21
Is reflected by a mirror 23, shaped into a rectangular spot by a mask 24, and irradiated onto a semiconductor substrate 30 in a container 26 by an imaging lens 25. In this case, as shown in FIG.
Although the spot shape of the laser light 22 on the semiconductor substrate 30 is a quadrangle regulated by the mask 24,
Since No. 2 has once passed through the focal point position, when examined in detail, most of the light present in the spot is incident on the semiconductor substrate 30 from an oblique direction.

When the inside of the container 26 is in a vacuum state of about 10 ⁻⁵ Pa, the semiconductor substrate 3 is caused by the irradiation of the laser beam 22.
The mean free path of the molten metal vapor 33 radiated from 0 is on the order of meters, and since it goes in a substantially vertical direction regardless of the incident angle of the laser beam 22, the through hole 32 of the shield plate 32
Instead of going in the a direction, it goes to the lower surface 32b of the shielding plate 32 immediately above the irradiation position. Therefore, the molten metal vapor 33 is efficiently captured by the lower surface 32b of the shielding plate 32.

Further, since the shield plate 32 is arranged at the focal position of the imaging lens 25, the inner diameter of the through hole 32a formed in the shield plate 32 is set to the minimum value at which the narrowed laser light 22 passes. Can be set. Therefore, by setting the inner diameter of the through hole 32a small without reducing the energy of the laser beam 22 applied to the semiconductor substrate 30, the molten metal vapor 33 emitted from the semiconductor substrate 30 can be reliably shielded from the shield plate 32. Can be captured on the lower surface 32b of the.
Molten metal vapor 33 that passes through the through hole 32a and leaks above the shielding plate 32 can be suppressed to a value that can be almost ignored.

As a result, it is possible to prevent the molten metal vapor 33 from adhering to the glass 27 fitted in the window 28 of the container 26. Next, the XY table 29 is driven to drive the laser beam 22.
A method for scanning the semiconductor substrate 30 will be described with reference to FIG. As shown in FIG. 3, the spot shape 34 of the laser beam 22 on the semiconductor substrate 30 is a square with one side a. The orientation of the mask 24 is adjusted in advance so that the diagonal line 34a of the square spot shape 34 faces the X direction.

When scanning the semiconductor substrate 30 with the laser light 22, first, the laser light 22 is irradiated in order while moving the XY table 29 by a minute distance dX in the X direction. When the scanning for one row in the X direction is completed, the irradiation position of the laser beam 22 is moved in the Y direction by 1/2 of the diagonal line 34a, that is, by (2 ^1/2 / 2) a. Then, the laser light 22 is sequentially irradiated again while moving from this position in the −X direction by a small distance dX.

In the laser light irradiation apparatus incorporating such a scanning method, the irradiation number n of the laser light 22 at each position on the semiconductor substrate 30 will be verified. In FIG.
The scanning speed is v, the repetition irradiation frequency of the laser light 22 is f
And the scanning direction length of the spot shape 34 is L, the number of irradiations n at an arbitrary point is n = L / v · f. For example, one point 3 on the diagonal of the spot shape 34
5a, the number of irradiations n _a (n _c) at 35c, since the scanning direction length L is the diagonal length ^{(2 1/2) a L = (} 2 1/2) a n a = (2 1/2) a / V · f. Further, the scanning direction length L at the point 35b moved by ¼ of the diagonal line 34a in the Y direction, that is, by (2 ^1/2 / 4) a becomes (2 ^1/2 / 2) a, and the forward path and the return path. Therefore, the irradiation number n _b of the point 35b is n _b = [(2 ^1/2 / 2) a + (2 ^1/2 / 2) a] / v ·
f = (2 ^1/2 ) a / v · f. That is, most of the irradiation area has the same irradiation frequency. However, as shown in FIG. 4, the number of times of irradiation is small only in the peripheral portion of the irradiation region. The area width of the peripheral portion where the number of times of irradiation is small corresponds to a corner portion of the spot shape 34, and the width is half (2 ^1/2 / 2) a of the diagonal line 34a, which is a value that can be almost ignored.

Thus, even if the small spot shape 3
Even if the semiconductor substrate 30 is scanned with the laser beam 22 having the number 4, the irradiation can be performed with uniform energy over almost the entire illumination region. Therefore, the uniformity of the process of the semiconductor manufacturing process on the semiconductor substrate 30 using the laser light irradiation is improved, and the process accuracy can be significantly improved.

In the apparatus of the embodiment, the scoot shape 34 is square, but it may be rectangular or rhombic, for example. Furthermore, in the embodiment, the laser light 22 is a pulsed laser light that repeats blinking at a constant cycle (frequency f), but may be continuous light, for example.

FIG. 5 is an optical system diagram of a laser irradiation apparatus according to another embodiment of the present invention. The laser light 22 output from a laser light source (not shown) is focused by an entrance lens 36 on an entrance surface 37a of a kaleidoscope 37 as a homogenizer. Kaleidoscope 37 (Kaleidoscope), as is well known, the reflective surfaces a plurality of mirrors having a strip shape is a cylinder having a square cross-section have a disposed structure to face
ing. The light incident from the incident surface 37a at the upper end of the cylinder is repeatedly reflected by each mirror a plurality of times, and the light exit surface 37b at the lower end of the cylinder.
It is output from the whole. Then, as the reflection is repeated, the light intensity of the laser light is made uniform, and as shown in the figure, the light intensity of the laser light output from the entire emission surface 37b at the lower end is averaged.

The exit surface 37 at the lower end of the kaleidoscope 37
The laser light 22 emitted from b is transmitted through the glass 27 of the window of the container 26 by the imaging lens 25 and is irradiated onto the semiconductor substrate 30 in the container 26.

In this case, the image focused by the imaging lens 25 at the focused spot position B in the container 26 is the focused spot position A of the entrance lens 36 (the entrance surface 37a of the kaleidoscope 37). Since the image at the focus spot position A is reflected by each mirror in the kaleidoscope 37, a number of focus spots corresponding to the number of reflections are generated at the focus spot position B in the container 26.

Position of image forming lens 25 and focus spot position B
And the distance B ₁ between it and the focal spot position A of the entrance lens 36
If the distance between the (incident surface 37a of the kaleidoscope 37) and the position of the imaging lens 25 is defined as B ₂ , the positional relationship among the kaleidoscope 37, the imaging lens 25, and the focused spot position B is The following relationship is satisfied using the focal length F of the lens 25.

1 / B ₁ + 1 / B ₂ = 1 / F Therefore, the shield plate 3 is placed at the focus spot position B shown in the above equation.
8 is provided. In this case, since the number of focused spots corresponding to the number of reflections is generated at the focused spot position B,
As shown in the figure, the shield plate 38 is provided with a plurality of through holes 38a corresponding to the respective focused spots. The diameter of each through hole 38a is set to a value slightly larger than the focused spot.

Each laser beam 22 passing through each through hole 38a of the shield plate 38 forms an image on the semiconductor substrate 30. In this case, the image formed on the semiconductor substrate 30 is a square inverted image of the exit surface 37b of the kaleidoscope 37.

Also in the laser light irradiation apparatus having such a configuration, the semiconductor substrate 30 can be irradiated with the laser light 22 from an oblique direction, and the molten metal vapor radiated upward from the irradiation position of the semiconductor substrate 30 can be reliably prevented by the shielding plate 38. Can be captured in

FIG. 6 is a view showing a container portion of a laser beam irradiation apparatus according to another embodiment of the present invention as taken out. The container 26 in the apparatus of this embodiment includes an upper first chamber 39a having a window 28 in which a glass 27 is fitted and a lower second chamber 39b containing a semiconductor substrate 30. Has been done. A shielding plate 40 having a through hole is fitted in the boundary between the first room 39a and the second room 39b.

An inert gas such as argon Ar is supplied to the first chamber 39a from the outside. Also, the second
An exhaust port 39c communicating with an exhaust pump (not shown) for maintaining the second chamber 39b in a vacuum state at atmospheric pressure or lower is formed below the chamber 39b. Since the through hole formed in the shielding plate 40 is sufficiently small, the degree of vacuum in the second chamber 39b can be sufficiently secured.

In the laser light irradiation apparatus configured as described above, a small amount of inert gas is always passed through the small-diameter through hole of the shield plate 40 from the first chamber 39a to the second chamber 39b.
Since the molten metal vapor radiated from the semiconductor substrate 30 does not easily enter the first chamber 39a through the through-hole, even if it enters, the atmospheric pressure is higher than that in the second chamber 39b. Since it is expensive, it falls before reaching the glass 27 of the window 28.

In this way, the container 26 is placed in the two upper and lower chambers 3
The window 2 of the container 26 is divided into 9a and 39b.
The molten metal vapor is reliably prevented from adhering to the glass 27 of No. 8.

The present invention is not limited to the above embodiments. In the apparatus of the embodiment, the kaleidoscope 37 shown in FIG. 5 is adopted as the homogenizer. However, as shown in FIG. 7, for example, a plurality of small lenses 40a are arranged in a cylinder in a plane and one image lens 40b is used. It is also possible to use the array lens 41 for making the light intensity distribution within the spot shape of the output laser light uniform.

Further, even in the laser light irradiation device incorporating a homogenizer such as the kallide scove 37 and the array lens 41, the semiconductor substrate 30 can be irradiated with the laser light 22 in the form of a small rectangular spot.
The Y table 29 can be moved and controlled to scan the laser beam 22 in the spot-shape diagonal direction. Therefore, it is possible to irradiate the semiconductor substrate 30 with the laser light 22 more uniformly.

[0058]

As described above, in the laser light irradiating apparatus and the laser light irradiating method of the present invention, the laser light is obliquely applied to the semiconductor substrate in the container by using, for example, an imaging lens, Moreover, an air shielding plate for capturing the molten gold vapor is arranged above the irradiation position. Therefore, it is possible to prevent the molten gold vapor from adhering to the window of the container into which the laser light is incident.

Further, the spot shape on the semiconductor substrate is quadrangular, and the laser beam is scanned in the diagonal direction of the quadrangle. Therefore, the entire irradiation region of the semiconductor substrate can be irradiated with a uniform light intensity while having a small spot shape.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a laser light irradiation apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a main part of the apparatus according to the embodiment.

FIG. 3 is a diagram showing a laser beam spot shape and a scanning method in the apparatus of the embodiment.

FIG. 4 is a characteristic diagram showing the number of times laser light is irradiated onto the semiconductor substrate in the apparatus of the embodiment.

FIG. 5 is an optical system diagram of a laser light irradiation device according to another embodiment of the present invention.

FIG. 6 is a schematic sectional view of a container of a laser light irradiation apparatus according to yet another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a homogenizer incorporated in a laser light irradiation apparatus according to still another embodiment of the present invention.

FIG. 8 is a schematic sectional view showing a schematic configuration of a conventional laser light irradiation device.

FIG. 9 is a diagram showing a laser beam spot shape and a scanning method in a conventional laser beam irradiation device.

FIG. 10 is a diagram showing a laser beam spot shape and a scanning method in the same conventional laser beam irradiation apparatus.

FIG. 11 is a diagram showing a laser beam spot shape and a scanning method in the same conventional laser beam irradiation apparatus.

[Explanation of symbols]

21 ... Laser light source, 22 ... Laser light, 23 ... Mirror, 24 ...
Mask, 25 ... Imaging lens, 26 ... Container, 27 ... Glass, 28 ... Window, 29 ... XY table, 30 ... Semiconductor substrate, 31 ... Exhaust port, 32, 38 ... Shielding plate, 32a, 38
a ... Through hole, 33 ... Molten gold vapor, 34 ... Spot shape, 34a ... Diagonal line, 36 ... Incident lens, 37 ... Kaleidoscope, 39a ... First room, 39b ... Second room, 41 ... Array lens

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification FI // H01L 21/3205 B23K 101: 40 B23K 101: 40 H01L 21/88 Z

Claims (5)

(57) [Claims] 1. A laser light source and a color on which laser light emitted from the laser light source is incident.
Image the laser beam emitted from the ididescope and this kaleidoscope
The imaging lens and the inside can be maintained in a vacuum state below atmospheric pressure.
The XY table for mounting the body substrate and the laser light are
A container having a window fitted with glass for transmission
And each focusing spot of laser light by the imaging lens
And a shielding plate having a plurality of through holes arranged
And a focal length of the image forming lens is F, and the image forming lens position is
The distance from the focused spot position is B ₁ , the position of the imaging lens
And the distance from the entrance surface of the kaleidoscope is B ₂ ,
1 / F = 1 / B ₁ + 1 / B ₂ is satisfied, and the image of the exit surface of the kaleidoscope is on the semiconductor substrate.
A laser light irradiation device, which is configured to form an image on a laser light irradiation device. 2. Laser light emitted from the laser light source
Incident lens for condensing light onto the incident surface of the kaleidoscope
The laser beam irradiation according to claim 1, further comprising:
apparatus. 3. The kaleidoscope regulates the spot shape of the laser light output from the laser light source to a quadrilateral shape, and the XY table has a quadrilateral spot shape irradiated on the semiconductor substrate. a laser beam, according to claim, characterized in that to scan in a diagonal direction of the quadrilateral 1 or
2. The laser light irradiation device according to 2. 4. The container is partitioned into a first room in contact with the translucent plate and a second room containing the semiconductor substrate with the shielding plate as a boundary, and an inert gas is introduced into the first room. The laser light irradiation device according to claim 1 , wherein the second chamber is kept at atmospheric pressure or less. 5. A laser for irradiating a semiconductor substrate with laser light.
In the light irradiation method, a predetermined spot-shaped laser light is applied onto the semiconductor substrate.
Irradiation in order while moving a minute distance in the first direction in
The forward pass step of finishing the scanning for one row and the laser light in the second direction orthogonal to the first direction.
The spot shapes before and after shifting the irradiation position partially overlap.
Shift step for shifting the laser beam in the predetermined spot shape and the laser beam having the predetermined spot shape in the first direction.
Irradiate in order while moving a small distance in the opposite direction
A return pass process for finishing scanning for one row, and the number of irradiations performed in the forward pass process and the return pass process is
The number of irradiations is the same regardless of the position in the first direction.
A method for irradiating a laser beam, which is characterized in that