JP2001250790A - Laser treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a laser treatment of a large area semiconductor coating with high throughput while suppressing variation in the characteristics among a plurality of semiconductor elements formed by laser annealing. SOLUTION: First and second adjacent element forming regions are formed on a substrate, the first element forming region is scanned along a first scanning path by a laser beam having linear cross-section, and the second element forming region is scanned along a second scanning path by a laser beam having linear cross-section, thus dividing the substrate into a first element substrate having the first element forming region and a second element substrate having the second element forming region. In such a laser treating method, the substrate is divided such that a region irradiated with both laser beams along the first and second scanning paths is located on the outside of the element substrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin film transistor (T) formed on a substrate having a non-single-crystal crystalline silicon film.
The present invention relates to a laser processing method and a laser processing apparatus used in a photo-annealing process related to the production of a semiconductor device such as FT).

[0002]

2. Description of the Related Art In recent years, studies have been made on an insulating gate type semiconductor device having a thin-film active layer (also called an active region) on an insulating substrate. In particular, a thin film gate transistor, a so-called thin film transistor (TFT), has been enthusiastically studied. These are classified into amorphous silicon TFTs and crystalline silicon TFTs depending on the material and crystal state of the semiconductor used. Although crystalline silicon is not single crystal, it is non-single crystal. Therefore, these are collectively referred to as non-single-crystal silicon TFTs.

Generally, the electric field mobility of a semiconductor in an amorphous state is small, and therefore, a TF which requires high-speed operation is required.
Not available for T. Further, in the case of amorphous silicon, the P-type electric field mobility is extremely small, so that a P-channel TFT (PMOS TFT) cannot be manufactured.
T) and complementary MOS circuit (CMOS)
Cannot be formed.

On the other hand, a crystalline semiconductor has a higher electric field mobility than an amorphous semiconductor, and therefore can operate at high speed. In crystalline silicon, not only NMOS TFTs but also PMOS TFTs can be obtained in the same manner.
An OS circuit can be formed.

A non-single-crystal crystalline silicon film is obtained by thermally annealing an amorphous silicon film obtained by a vapor deposition method at an appropriate temperature (usually 600 ° C. or higher) for a long time or by intense light such as laser. It was obtained by irradiation (light annealing).

However, when an inexpensive and highly processable glass substrate is used as the insulating substrate, a crystalline silicon film having a sufficiently high electric field mobility (high enough to form a CMOS circuit) can be formed only by thermal annealing. Getting it was extremely difficult. This is because the glass substrate as described above generally has a low strain point temperature (about 600 ° C.) and cannot raise the substrate temperature to a temperature necessary to obtain a crystalline silicon film having sufficiently high mobility. It is.

On the other hand, when optical annealing is used for crystallization of a silicon film based on a glass substrate, high energy can be applied only to the silicon film without increasing the temperature of the substrate so much. Therefore, it is considered that the optical annealing technique is very effective for crystallization of a silicon film based on a glass substrate.

At present, a high output pulse laser such as an excimer laser is most suitable as a light source for optical annealing. The maximum energy of this laser is much larger than that of a continuous wave laser such as an argon ion laser, and therefore, mass productivity can be further improved by using a large spot of several cm ² or more. However,
With a commonly used square or rectangular shaped beam, it is necessary to move the beam up, down, left and right to process one large area substrate, and there is still room for improvement in terms of mass productivity.

In this regard, the beam is deformed linearly,
Beam length (longitudinal size of linear beam cross section)
Can be greatly improved by making the length longer than the substrate to be processed and moving and scanning this beam relative to the substrate. Here, the scanning means that the linear laser is moved in the line width direction (the direction orthogonal to the longitudinal direction of the linear beam cross section) and the irradiation area is not divided.
Irradiation means overlapping. In general, when irradiating a linear laser beam over a large area, the scanning path is made parallel.

Further, by performing thermal annealing before optical annealing, a silicon film having higher crystallinity can be manufactured.
Regarding the method by thermal annealing, see JP-A-6-2441.
As described in No. 04, elements such as nickel, iron, cobalt, platinum and palladium (hereinafter referred to as crystallization catalyst elements or simply catalyst elements) utilize the effect of promoting the crystallization of amorphous silicon. Thus, a crystalline silicon film can be obtained by thermal annealing at a lower temperature and for a shorter time than usual.

[0011]

However, due to its maximum energy, the linear laser beam is irradiated with a linear laser beam whose length (the length of the laser beam cross section in the longitudinal direction) is long. Processing was limited to about 20 cm.

If the laser beam is processed to a longer length, the energy density of the laser beam becomes insufficient for crystallizing, for example, an amorphous silicon film. Therefore, when using a large-area substrate and performing laser processing on an area that exceeds the length of the linear laser, the scanning of the laser beam is performed in the vertical and horizontal directions, that is, in both the line width direction and the length direction. Had to be moved. FIG. 13 schematically shows a conventional laser beam scanning path.

FIG. 13A is a cross-sectional view of a linear laser beam, and FIG. 13B is a view of the irradiated surface viewed from above. As shown in FIG. 13A, the end 1a of the linear laser beam 1 is not a perfect rectangle, and the energy density in this portion is dispersed.

As shown in FIG. 13B, the linear laser beam 1 is scanned along two scanning paths 2 and 3. For example, the linear laser beam 1 is scanned on the left scanning path 2
Is scanned downward along the scanning path 3, and then scanned downward along the right scanning path 3. At this time, it is necessary to perform scanning so that the end portions 1a of the linear laser beam 1 overlap. However, how to overlap the end portions 1a of the linear laser beam 1 becomes a problem. In FIG. 13B, a region 4 indicated by a rectangle is a region where the region where the end 1a of the linear laser beam 1 overlaps on the irradiated surface is scanned.

However, since it is generally difficult to control the energy density at the end 1a of the linear laser beam 1, the semiconductor element manufactured in the region 4 and the vicinity thereof is smaller than the elements provided in other parts. , Characteristic variations were conspicuous. Therefore, the semiconductor material in the region 4 is not suitable for processing a semiconductor element.

As a countermeasure against the above-mentioned problem, a laser beam is irradiated through a slit to shield an end portion in a length direction where energy density is difficult to control, thereby shaping the end portion of the laser beam. . FIG. 14A is a cross-sectional view of a linear laser beam shaped by a slit, and FIG. 14B is a schematic view of a scanning path of the laser beam, and is a diagram of the irradiated surface viewed from above. .

As shown in FIG. 13A, the end 5a of the laser beam 5 is shaped into a rectangle by passing through the slit, so that the energy density distribution at the end 5a is linear as shown in FIG. It becomes more uniform than the laser beam 1.

As shown in FIG. 14B, when the linear laser beam 5 is irradiated, for example, the linear laser beam 5 is scanned downward along the left scanning path 6 and then to the right scanning path 7 To scan down along. At this time, the end 5a of the linear laser beam 5
Are scanned so as to overlap each other.
a is shaped in a rectangular shape, and its energy density distribution is uniform.
a may be overlapped to the extent that the end portions 5a overlap.
Can be reduced.

However, even if the energy density of the end 5a of the laser beam 5 is controlled by using the slit, the characteristics of the semiconductor element formed in the scanned region 8 where the end 5a of the laser beam 5 overlaps still remain. Has a remarkable variation in characteristics as compared with devices manufactured in other regions.

An object of the present invention is to provide a laser processing method and a laser processing apparatus capable of solving the above-mentioned problems and performing a laser annealing step on a large-area semiconductor film at a high throughput.

Another object of the present invention is to provide a laser processing method and a laser processing apparatus for a semiconductor film having a large area, which can suppress variations in characteristics among a plurality of semiconductor elements.

[0022]

According to one aspect of the present invention, there is provided a semiconductor device which scans a laser beam having a linear cross section and has a width larger than the length of the cross section of the laser beam. Laser irradiation is performed on the coating, and when annealing is performed, the semiconductor device is not formed in a region where the laser light is irradiated in contact with the end portions in the longitudinal direction of the laser light. is there.

According to another configuration of the present invention, when irradiating a semiconductor film on a substrate with a laser beam having a linear cross section while scanning a plurality of rows, the semiconductor film on the substrate includes a plurality of elements separated from each other. Having a region, the cross-section of the linear laser light, the region irradiated with overlapping end portions in the longitudinal direction of the cross-section, so as to be located outside each element region in the semiconductor coating, A laser processing method, wherein the laser beam is scanned.

According to another configuration of the present invention, the semiconductor film on the substrate is a laser beam having a linear cross section, and the length of the cross section of the linear laser is shorter than the size of the element region of the semiconductor film. When irradiating while scanning the laser light, the linear laser light is irradiated on the semiconductor film through a slit, and the end portion in the length direction of the linear laser beam is cut, and the linear laser light is scanned. In this way, a laser-processed portion is formed by laser-processing one part of the element region, and an end of the laser beam in the length direction when the laser-processed portion is scanned with respect to a laser-unprocessed portion of the element region. And a laser processing method in which the laser processing is performed such that the end portions in the length direction of the linear laser light passing through the slit to be newly irradiated come into contact.

According to another configuration of the present invention, the semiconductor film on the substrate is a laser beam having a linear cross section, and the length of the cross section of the linear laser is shorter than the size of the element region of the semiconductor coating. When irradiating while scanning the laser light, the linear laser light whose longitudinal end portion is cut through a slit, by scanning and irradiating the semiconductor coating, the laser element, the element Forming a laser-processed portion by laser-processing one part of the region, and a laser-unprocessed portion of the element region, an end portion in the length direction of the laser beam when scanning the laser-processed portion;
The end portion in the length direction of the linear laser light passing through the slit to be newly irradiated is 10 to 20 in the length direction of the linear laser beam.
A laser processing method characterized by performing laser processing so as to overlap and contact in a range of μm.

According to another structure of the present invention, the semiconductor film on the substrate is a laser beam having a linear cross section, and the length of the cross section of the linear laser is shorter than the size of the element region of the semiconductor film. When irradiating while scanning the laser light, the linear laser light is irradiated on the semiconductor film through a slit, and the end portion in the length direction of the linear laser beam is cut, and the linear laser light is scanned. In this way, a laser-processed portion is formed by laser-processing one part of the element region, and an end of the laser beam in the length direction when the laser-processed portion is scanned with respect to a laser-unprocessed portion of the element region. Laser processing is performed so that the end portions in the length direction of the linear laser light passing through the newly irradiated slit are in contact with each other, and the contacting position is determined in a subsequent step by a semiconductor element provided. A laser processing method which is a free position.

According to another configuration of the present invention, the semiconductor film on the substrate is a laser beam having a linear cross section, and the length of the cross section of the linear laser is shorter than the size of the element region of the semiconductor coating. When irradiating while scanning the laser light, the linear laser light whose longitudinal end portion is cut through a slit, by scanning and irradiating the semiconductor coating, the laser element, the element Forming a laser-processed portion by laser-processing one part of the region, and a laser-unprocessed portion of the element region, an end portion in the length direction of the laser beam when scanning the laser-processed portion;
The end portion in the length direction of the linear laser light passing through the slit to be newly irradiated is 10 to 20 in the length direction of the linear laser beam.
The laser processing method is characterized in that laser processing is performed so as to overlap and contact in a range of μm, and the contact position is a position where a semiconductor element is not provided in a subsequent step.

Further, in the above structure, the substrate is characterized by constituting a liquid crystal display.

[0029]

The present invention scans a linear laser beam,
Laser irradiation is performed on the semiconductor film having a width larger than the cross-sectional length of the laser beam, and when annealing is performed, the end portions 1 of the laser beams 1 and 5 as shown in FIG.
A semiconductor element is not formed in a region irradiated with the overlapped portions a and 5a.

In other words, control is performed so that the region irradiated with the end portions in the longitudinal direction of the laser beam overlapping or in contact with each other is not located on the element region of the semiconductor film (the region where the semiconductor element is provided). And laser irradiation.

By doing so, it becomes possible to perform laser annealing with high throughput and to suppress variation in characteristics between semiconductor elements, no matter how large the substrate is and the area to be irradiated becomes large. .

[0032]

Embodiment 1 FIGS. 1 to 3 are configuration diagrams of a laser irradiation apparatus of the present embodiment, FIG. 1 is a top view, and FIG. 2 is a cross-sectional view taken along a dotted line AA ′ in FIG. FIG. 3 is a cross-sectional view taken along a dotted line BB ′ in FIG. The laser irradiation apparatus of this embodiment is a multi-chamber type apparatus, and is a single-wafer type apparatus capable of continuously processing many substrates (samples) one by one.

A large number of substrates 10 to be processed are stored in a cartridge 11, and the entire cartridge 11 is carried into an apparatus.

In the substrate transfer chamber 13 for transferring the substrate 10 in the apparatus, the cartridge loading / unloading chamber 17, the heating chamber 18, the laser irradiation chamber 1 are operated by gate valves 14 to 15.
9 are connected to each other. Substrate transfer chamber 13, cartridge loading / unloading chamber 17, heating chamber 18, laser irradiation chamber 1
A gas supply system 20 to supply gas, an inert gas or the like is connected to the upper part, and an exhaust system 29 to 32 to which vacuum pumps 25 to 28 are connected. It is connected to the. Thereby, the substrate transfer chamber 13, the cartridge loading / unloading chamber 17, the heating chamber 1
8. The atmosphere, pressure and the like in the laser irradiation chamber 19 can be controlled.

A robot arm 33 is provided in the substrate transfer chamber 13.
Is provided, and the substrates 10 can be transferred one by one to the cartridge loading / unloading chamber 17, the laser irradiation chamber 19, or the heating chamber 18. Further, an alignment mechanism 34 is provided on the gate valve 14 side, and the substrate 10 and the robot arm 33 are aligned.

In the heating chamber 18, a large number of substrates 10 can be stored on an elevator 35, and the substrate 10 can be heated to a predetermined temperature by a heating means 36 composed of a resistor or the like.

The laser irradiation chamber 19 contains the substrate 10
Is provided on the stage 37. The stage 37 has a heating unit for heating the substrate 10,
In addition, a guide mechanism, a motor, and the like (not shown) make it possible to move horizontally in the two-dimensional direction in the plane of FIG. 1 and to rotate about an axis perpendicular to the plane of the paper. Further, on the upper surface of the laser irradiation chamber 19, there is provided a quartz window 38 into which laser light emitted from the outside of the apparatus enters.

As shown in FIG. 2, a laser irradiating means 39 is provided outside the apparatus, and a mirror 40 is disposed on an optical path 41 of the laser irradiating means 39 in a laser light emitting direction. A quartz window 38 of the laser irradiation chamber 19 is provided on the light path 41 thus formed, and the laser light emitted from the laser irradiation means 39 is reflected by the mirror 40, passes through the quartz window 38, and is placed on the stage 37. Irradiated at 10.

FIG. 4 is a schematic structural view of the laser irradiation means 39. Total reflection mirrors 52 and 53 are arranged on an optical path 50 in the emission direction of an oscillator 51 for oscillating a laser.
An amplifier 5 is provided on the optical path 50 in the reflection direction of the total reflection mirror 53.
4. Attenuating means 5 composed of a plurality of filters 55a to 55d
5. An optical system 56 for linearly shaping the laser light is sequentially arranged.

The attenuating means 55 is for adjusting the laser energy, and the filters 55a to 55d have the function of attenuating the energy of the transmitted light, and their transmittances are different from each other. Filters 55a-5
The transmittance of 5d was 96%, 92%, 85%, and 77%, respectively.
%. These filters 55a to 55d can be inserted and removed independently from the optical path 50 by driving means such as an electromagnet and a motor (not shown). By appropriately combining the filters 55a to 55d, a filter having a transmittance of 57 to 96% can be formed. For example, a filter 55a having a transmittance of 96% and a neutral density filter 55b having a transmittance of 92%
By combining the above, a neutral density filter having a transmittance of 88% can be obtained.

The filters 55a to 55d are made by alternately coating quartz with hafnium oxide and silicon dioxide in layers, and the transmittance of the neutral density filters 55a to 55d depends on the number of coated layers. In this embodiment, the number of filters 55a to 55d of the attenuation means 55 is set to 4
The number of filters is not limited to this number, and the number of filters and the transmittance thereof may be determined so that laser energy can be appropriately adjusted.

FIGS. 5 and 6 are diagrams showing the configuration of the optical system 56.
FIG. 6 corresponds to a cross-sectional view along the optical path 50 of FIG. As shown in FIGS. 5 and 6, on the optical path 50, in order from the incident direction, a cylindrical concave lens 61, a cylindrical convex lens 62, fly-eye lenses 63 and 64 having axes perpendicular to each other, cylindrical convex lenses 65 and 66,
The total reflection mirror 67 is arranged, and a cylindrical lens 68 is disposed on the optical path in the reflection direction of the total reflection mirror 67.

In the laser irradiation means 39 shown in FIG. 4, the laser light oscillated by the oscillator 51 is reflected by total reflection mirrors 52 and 53, respectively, and is incident on the amplifier 54. The laser light is amplified by the amplifier 54 and reflected by the total reflection mirrors 55 and 56, respectively.
5, the light reaches the optical system 56, and passes through the cylindrical concave lens 61, the cylindrical convex lens 62, and the fly-eye lenses 63 and 64 as shown in FIGS. It is changed to a shape distribution. Further, the cylindrical convex lens 6
5 and 66, reflected by the total reflection mirror 67,
The light is converged by the cylindrical lens 68 and formed into a linear beam image at the focal plane f. This linear beam image has a longitudinal direction in a direction perpendicular to the paper surface in FIG.

The shape of the laser beam is a rectangle of about 3 × 2 cm ² immediately before entering the optical system 56.
After that, it is formed into an elongated linear beam having a width of about 10 to 30 cm and a width of about 0.1 to 1 cm.

When laser annealing is performed by the laser irradiation apparatus shown in FIGS. 1 to 3, first, the gate valves 14 to 16 are closed, and the substrate transfer chamber 13, the laser irradiation chamber 19, and the heating chamber 18 are placed in a nitrogen atmosphere. Fill with gas.

Next, the cartridge 11 containing a large number of the substrates 10 is loaded into the cartridge loading / unloading chamber 17 from outside. A door (not shown) is provided in the cartridge loading / unloading chamber 17, and by opening and closing the door,
Carry in / out of the cartridge 11 is performed. Cartridge 1
After loading the cartridge 1 into the cartridge loading / unloading chamber 17, the door is closed, the cartridge loading / unloading chamber 17 is closed, nitrogen gas is supplied from the gas supply system 21, and the cartridge loading / unloading chamber 17 is filled with nitrogen gas. Let it. It should be noted that the cartridge loading / unloading chamber 17 is not in a depressurized state but is in an atmospheric pressure state. Next, the gate valve 14 and the gate valve 15 are opened. The gate valve 14 may be kept open until a series of steps is completed.

The substrates 10 are taken out one by one from the cartridges 11 installed in the cartridge loading / unloading chamber 17 by the robot arm 33, placed on the alignment mechanism 34, and the positions of the robot arms 33 and the substrates 10 are once aligned. Thereafter, the substrate 10 is picked up again by the robot arm 33 and transferred to the heating chamber 18. Substrate 1 in heating chamber 18
Every time 0 is transferred, the elevator 35 is raised or lowered, and the substrates 10 are stored in a state of being sequentially stacked.

After a predetermined number of substrates 10 have been carried in the heating chamber 18, the gate valve 15 is closed and the heating means 3
The substrate 10 is heated by 6. When the substrate 10 is heated to a predetermined temperature, the gate valve 15 is opened, and the substrate 10 is transferred from the heating chamber 18 to the substrate transfer chamber 13 by the robot arm 33, placed on the alignment mechanism 34, and positioned again. Is performed.

When the gate valve 16 is opened, the substrate 10 on the alignment mechanism 34 is
Is placed on the stage 37 of the laser irradiation chamber 19, and the gate valve 15 and the gate valve 16 are closed. The gate valve 15 is preferably opened and closed each time the substrate is unloaded. This is to prevent the atmosphere of the heating chamber 18 from thermally affecting the mechanical configuration of the robot arm 33 and the like.

After closing the gate valve 16, a linear beam is emitted from the laser irradiating means 39, and the linear laser irradiates the substrate 10 on the stage 37 through the mirror 40 and the quartz window 38. When the stage 37 rotates and moves horizontally, the substrate 10 is irradiated with a linear laser along a predetermined scanning path. During irradiation with laser light,
The substrate 10 is heated to the same temperature as the temperature in the heating chamber 18 by the heating means provided on the stage 37, and thermal fluctuation is suppressed. When the laser beam irradiation is completed,
The gate valve 16 is opened, and the substrate 10 is stored in the cartridge 11 in the cartridge loading / unloading chamber 17 by the robot arm 33. Thus, the processing for one substrate 10 is completed.

When the processing of one substrate 10 is completed, the gate valve 15 is opened, and the next substrate 10 is taken out of the heating chamber 18 by the robot arm 33 and transferred to the laser irradiation chamber 19, where the stage 37 Placed on the
Laser light is applied. In this manner, the substrate 10 accommodated in the heating chamber 404 is irradiated with the laser light one by one. When all processes are completed, the processed substrate 1
0 are all stored in the cartridge 11 installed in the cartridge loading / unloading chamber 17. The cartridge 11 may be taken out of the cartridge loading / unloading chamber 17 and then proceed to the next step.

The heating temperature in the heating chamber 18 needs to be lower than the temperature at which the amorphous silicon film is crystallized. This is because the time in the heating chamber differs depending on the substrate 10. Generally, the heating temperature in the heating chamber 18 is 2
It is selected to be about 00 to 400 ° C. The heating temperature needs to be the same as the heating temperature of the substrate 10 when the laser beam is irradiated.

Embodiment 2 In this embodiment, an example is described in which a crystalline silicon film for manufacturing a semiconductor element is manufactured using a substrate having a size exceeding the width of a linear laser beam. FIG. 7 shows a manufacturing process diagram of the crystalline silicon film.

As shown in FIG. 7A, the glass substrate 71
(In this embodiment, a 360 mm × 460 mm Corning 7)
059), a silicon oxide film serving as a base film 72 having a thickness of 2000 ° and an amorphous silicon film 73 having a thickness of 500 ° were continuously formed by a plasma CVD method.

Then, 10 ppm was obtained by spin coating.
Was applied to the surface of the amorphous silicon film 73 and dried to form a nickel layer 74. It was better to add a surfactant to the aqueous nickel acetate solution. Since the nickel layer 74 is extremely thin, it does not always have a film shape, but does not cause any problem in the subsequent steps.

As shown in FIG. 7B, the amorphous silicon film 73 is crystallized by performing thermal annealing at 550 ° C. for 4 hours to obtain a crystalline silicon film 75. By the heating, nickel in the nickel layer 74 plays a role of a crystal nucleus, and promotes crystallization of the amorphous silicon film 73. Therefore, the crystalline silicon film 75 can be obtained at a low temperature of 550 ° C. for 4 hours (strain point temperature of Corning 7059 or less) and in a short time.

The catalyst in the crystalline silicon film 75
Element concentration is 1 × 10^Fifteen~ 1 × 10¹⁹Atom / cm^ThreeIn
I liked it. 1 × 10^FifteenAtom / cm^ThreeAt the following concentrations
If so, it is difficult to obtain a catalytic effect that promotes crystallization
Becomes 1 × 10¹⁹Atom / cm ^ThreeAt higher concentrations above,
The metallic properties appear in the capacitors, and the semiconductor properties disappear.
To do so. In this embodiment, the crystalline silicon film 7
The concentration of the catalyst element in 5 was 1 × 10 at the minimum value in the film.
¹⁷~ 5 × 10¹⁸Atom / cm^ThreeMet. Note that these values
Is analyzed and measured by secondary ion mass spectrometry (SIMS).
Specified.

In order to further enhance the crystallinity of the crystalline silicon film 75 thus obtained, as shown in FIG. 7C, the film 75 is irradiated with an excimer laser which is a high-power pulse laser. Then, a crystalline silicon film 76 having better crystallinity is formed.

When irradiating the laser, it is shown in FIGS.
Using a KrF excimer laser (wavelength 24
8 nm, pulse width 30 nsec) 1 mm x 185 mm
Shape linearly, first, 220mJ / cm^TwoDegree of energy
Irradiate the laser beam with energy and then the laser energy
Lug density of 100mJ / cm^Two~ 500mJ / cm ^Two
In the range of, for example, 370 mJ / cm^TwoIrradiation. Ma
Also, when focusing on one point of the irradiation target, 2 to 20 shots
Laser beam scanning so that laser light is irradiated
The speed, in fact, the movement of the stage 37 on which the substrate 71 is placed
Adjust the moving speed.

The laser energy of 220 mJ /
Switching from cm ² to 370 mJ / cm ² is performed by using the laser irradiation means 39 shown in FIG.
This is performed by selectively inserting and retracting 55d into the optical path 50. The substrate temperature during laser irradiation is 200 ° C.
And

The method of irradiating by changing the irradiation energy in this manner is called multi-step irradiation. In the case of this embodiment, the irradiation is performed twice, so that the irradiation is performed in two stages. With the two-step irradiation, the crystalline silicon film 76 can be formed more than in the one-step irradiation.
Can be further improved in crystallinity. In the case of one-step irradiation, the energy density of the laser should be 10
Irradiation may be performed in the range of 0 mJ / cm ^{2 to} 500 mJ / cm ² , for example, at 370 mJ / cm ² .

FIGS. 8A to 8D show the scanning path of the laser beam of this embodiment. As shown in FIGS. 8A to 8D, on a surface to be irradiated on the substrate 80, rectangular element manufacturing regions 81 in which thin film transistors are manufactured are arranged in a 2 × 2 matrix. Therefore, a semiconductor element is manufactured using only the crystalline silicon 76 in the element manufacturing area 81 on the glass substrate 71 shown in FIG. 7C. The substrate 80 on which the semiconductor element is manufactured is divided into four element substrates 86A to 86D as shown in FIG.

Also, as shown in FIG. 9, it is assumed that the substrate 80 is cut to a length equal to or less than the length of the linear laser beam after the semiconductor device is manufactured. The length L of the linear laser beam 82 in the longitudinal direction is set so that the region 4 or 8 where the end portions in the longitudinal direction are overlapped and irradiated is outside the device manufacturing region 81.
Is longer than the width W of the element manufacturing region 81.

In order to perform two-step irradiation, FIG.
As shown in (C), the scanning paths 83a to 83c are set so as to draw a linear stroke in parallel so that the linear laser beam 82 is irradiated twice to each of the element manufacturing regions 81. In the case of one-step irradiation, for example, as shown in FIG.
Further, the scanning paths 83a to 83c and 85 have a uniform direction with respect to all the element manufacturing regions 80 on the same substrate 80.

To scan the linear laser beam 83 along the scanning path shown in FIGS. 8A to 8C or 8D,
Irradiation may be performed while moving the linear laser beam 82 relative to the irradiated surface 80 along a direction substantially orthogonal to the longitudinal direction. Instead of actually moving the laser beam 82, in the laser irradiation apparatus shown in FIGS.
The substrate 80 having the surface to be irradiated is moved so that the linear laser beam 82 is scanned along the scanning path 83a, 83b or 83c.

In this embodiment, since the width W of the element forming region 81 is shorter than the length L of the linear laser beam 82, the end of the linear laser beam 82 does not scan the element forming region 81. Therefore, the film quality of the obtained crystalline silicon film 76 can be made uniform, so that the element fabrication region 81
The characteristics of the semiconductor element manufactured in the above can be made uniform. Further, by processing a large-area substrate 80, a large number of substrates on which semiconductor elements having the same characteristics are formed can be produced in one process, so that the throughput can be improved.

[Embodiment 3] In this embodiment, a process of manufacturing a thin film transistor for driving a pixel of a liquid crystal display using the crystalline silicon film 76 obtained in Embodiment 2 will be described. 10 and 11 show a manufacturing process of the thin film transistor of this embodiment.

As shown in FIG. 10A, the glass substrate 1
01, a silicon oxide film as a base film 102 is 3000
A crystalline silicon film 103 is deposited to a thickness of Å by a plasma CVD method or a low pressure thermal CVD method, and a crystalline silicon film 103 obtained by crystallizing an amorphous silicon film in accordance with the crystallization step described in the second embodiment is formed on the surface of the base film 102. Is formed.

Next, as shown in FIG. 10B, the crystalline silicon film 103 is etched into an island shape to form an element formation region 1.
A large number of active layers 104 are formed at predetermined positions in the area 00. In this embodiment, as shown in FIGS. 8 and 9, a thin film transistor is formed on the glass substrate 101 in order to divide the glass substrate 101 into four and obtain four identical element substrates. Rectangular element fabrication region 100
They are arranged in a × 2 matrix. Device fabrication area 1
A large number of active layers 104 are formed at predetermined positions in the area 00. Therefore, when the crystalline silicon film 103 is obtained, the end of the linear laser beam is prevented from passing through the inside of the element manufacturing region 100.

Next, the silicon oxide film 105 constituting the gate insulating film is formed in a thickness of 1000 to 1500 by the plasma CVD method.
Then, an aluminum film constituting the gate electrode 106 is deposited to a thickness of 5000 mm by sputtering. If scandium is previously contained in aluminum in an amount of 0.2% by weight, generation of hillocks and whiskers in a subsequent heating step or the like can be suppressed.

Next, the surface of the aluminum film is anodized to form a very thin dense anodic oxide (not shown). Next, a resist mask 107 is formed on the surface of the aluminum film. At this time, since a dense anodic oxide (not shown) is formed on the surface of the aluminum film, it can be formed by closely attaching the resist mask 107. Then, the aluminum film is etched using the resist mask 107 to form the gate electrode 106.

As shown in FIG. 10C, with the resist mask 107 left, the gate electrode 106 is anodized to form a porous anodic oxide 108 to a thickness of 4000 °. At this time, since the resist mask 107 is in close contact with the surface of the gate electrode 106, the porous anodic oxide 108 is formed only on the side surface of the gate electrode 106.

Next, as shown in FIG. 10C, after the resist mask 107 is peeled off, the gate electrode 106 is anodized again in an electrolytic solution to form a dense anodic oxide 10.
9 is formed to a thickness of 1000 °.

The formation of the anodic oxide may be changed by changing the electrolytic solution to be used. When forming the porous anodic oxide 108, citric acid, oxalic acid, chromic acid or sulfuric acid is used.
An acidic solution containing 酸性 20% may be used. On the other hand, when the dense anodic oxide 109 is formed, an electrolytic solution in which an ethylene glycol solution containing tartaric acid, boric acid, or nitric acid at 3 to 10% and the pH is adjusted to about 7 may be used.

As shown in FIG. 11A, the gate electrode 1
The gate insulating film 110 is formed by etching the silicon oxide film 105 using the porous anodic oxide 106 and the surrounding porous anodic oxide 108 and the dense anodic oxide 109 as a mask.

As shown in FIG. 11D, after removing the porous anodic oxide 108, the gate electrode 106, the dense anodic oxide 109, and the gate insulating film 110 are masked by an ion doping method. Then, impurities are implanted into the active layer 104. In this embodiment, in order to form a P-channel TFT, phosphine (PH) is used as a doping gas.
₃ ) Doping with phosphorus ions. At the time of doping, conditions such as a dose and an acceleration voltage are controlled so that the gate insulating film 110 functions as a semi-transparent mask.

As a result of the doping, phosphorus ions are implanted at a high concentration in the region not covered by the gate insulating film 110,
A source region 111 and a drain region 112 are formed.
Further, low-concentration impurity regions 113 and 114 are formed by implanting low-concentration phosphorus ions into a region covered only by the gate insulating film 110. Since no impurity is implanted into the region immediately below the gate electrode 106, the channel region 1
15 are formed.

Since the low-concentration impurity regions 113 and 114 function as high-resistance regions, they contribute to a reduction in off-state current.
In particular, the low concentration impurity region 113 on the drain region 112 side
Is called LDD. In addition, dense anodic oxide 10
9 is sufficiently thick so that a dense anodic oxide 10
9 can be set as the offset region, and the off-state current can be further reduced.

After the doping step, laser annealing is performed in the laser irradiation apparatus shown in FIGS. 1 to 3 to activate the doped phosphorus ions. The annealing condition at this time is that the energy density of the laser is 100 mJ.
/ Cm ^{2 to} 350 mJ / cm ² , for example, 16
0 mJ / cm ^2, and when focusing on an arbitrary point on the irradiated surface, a linear laser beam of 20 to 40 shots is irradiated, and the substrate temperature is kept at 200 ° C. In addition, the linear laser beam for one-stage irradiation is shown in FIG.
Scanning may be performed in accordance with the scanning path 85 shown in FIG. 9D. At this time, the end of the linear laser beam is
Do not pass through zero.

After the laser annealing, thermal annealing may be performed. In this case, heating may be performed at a temperature of 450 ° C. for about 2 hours.

As shown in FIG. 11C, the plasma CV
According to the D method, a silicon oxide film is
A film is formed to a thickness of 00 °. Note that as the interlayer insulator 116, instead of a single-layer film of a silicon oxide film, a single-layer film of a silicon nitride film or a stacked film of a silicon oxide film and a silicon nitride film may be formed. Next, a contact hole is formed in each of the source region 111 and the drain region 112 by etching the interlayer insulator 116 made of a silicon oxide film by a known etching method.

Next, an aluminum film is formed to a thickness of 4000 ° by a sputtering method, and is patterned to form an electrode 117118 connected to the source region 111 and the drain region 112.
19, a silicon nitride film is formed, and the passivation film 1 is formed.
19, a contact hole for the electrode 118 on the drain region 112 side is formed. Next, an ITO film is formed and patterned to form a pixel electrode 120 in a contact hole connected to the electrode.

Through the above steps, a TFT having an LDD structure is manufactured in the element manufacturing region 100 on the glass substrate 101. Lastly, as shown in FIG. 9, the substrate 101 is divided into element forming regions 100, whereby four panels of a liquid crystal display device can be obtained.

In this embodiment, the manufacturing process of an N-channel thin film transistor for driving a pixel of a liquid crystal display device has been described. However, a thin film transistor forming a peripheral driving circuit and a pixel in one element formation region 100 are described. May be formed at the same time. In this case, the conductivity type of the thin film transistor is controlled by using a known CMOS technology so that the thin film transistor constituting the peripheral driver circuit is a complementary thin film transistor including an N-channel thin film transistor and a P-channel thin film transistor. I just need.

[Embodiment 4] This embodiment relates to a scanning path of a laser beam when a substrate is not divided. In this case, as shown in FIGS. 13 and 14, the region 4 where the ends of the linear laser beam overlap or the region 8 in contact with the linear laser beam may be arranged in the element fabrication region. In such a case, regions 4 and 8 shown in FIGS.
The semiconductor element may be arranged so that the semiconductor element does not straddle (is not located or not approached).

For example, in FIG. 10, the active layer 104 of the thin film transistor is not overlapped with these regions 4 or 8, and the line of the linear laser beam is passed through the region 200 where the active layer 104 is not formed. What is necessary is just to adjust the length of a shape beam.

A portion (joint portion) where the end portions in the length direction of the linear laser beam are overlapped and irradiated is shown in FIG.
Whether they overlap to some extent as in the region 4 of FIG. 3 or contact only as in the region 8 in FIG. 14 depends on the density of the semiconductor elements on the substrate.

If the distance between the semiconductor elements is on the order of millimeters, the shape of the end of the linear laser beam, that is, the energy density distribution at the end does not matter.
As shown in (A), the linear laser beam 1 can be irradiated without shaping the end 1a. However, when the distance between the semiconductor elements is less than the millimeter order, the linear laser beam is shaped by a slit as shown in FIG. It is necessary to scan so that the ends of the shaped laser beam are in contact.

Further, if the distance between the semiconductor elements is on the order of several microns, even if a linear laser is scanned as shown in FIG. There is a possibility that an element may be formed in the area 8 where the end 5a of the laser beam 5 has passed, and it is difficult to manufacture the element while avoiding the area where the end 5a of the laser beam 5 has passed.

When a panel of a liquid crystal display is manufactured as a semiconductor element, for example, the interval between thin film transistors provided as a semiconductor element formed on the substrate is about 10 μm to 100 μm. Therefore, in this case, the linear laser beam is scanned so that the joint of the linear laser beam, that is, the end of the beam is in contact with the linear laser beam by cutting the end in the length direction using the slit. In this case, the seam portion is 10 to 20
If they are closely contacted with an accuracy of about μm, the accuracy is sufficient, and a liquid crystal display panel can be manufactured without forming a semiconductor element at the joint.

Embodiment 5 Embodiment 2 as shown in FIG.
In the figure, the element manufacturing regions 81 are arranged in a 2 × 2 matrix on the substrate 80. In order to uniformly irradiate the laser to the element manufacturing region, the element manufacturing region is preferably arranged symmetrically with respect to the substrate.
It is preferable to arrange them in a matrix of × 2n (n is a natural number of 1 or more). In this embodiment, as shown in FIG. 12, by using a substrate having a larger area, a 4 × 4 element manufacturing region 91 is arranged on a substrate 90, and one substrate is formed in one process. From 90, 16 substrates on which semiconductor elements having the same characteristics are manufactured are obtained.

In order to irradiate the linear laser beam 92 in two stages, for example, as shown in FIGS.
3A and 93B may be set. The length L of the linear laser beam 92 in the longitudinal direction is longer than the width W of the element manufacturing region 91 so that the linear laser beam 93 is uniformly irradiated. The region where the portions are overlapped and irradiated is set outside the element manufacturing region 91.

[0093]

According to the present invention, a laser annealing step for a semiconductor material having a large area can be performed at a high throughput. Further, according to the present invention, it was possible to suppress variation in characteristics among a plurality of semiconductor elements formed by laser annealing of a large-area semiconductor film.

The present invention is effective when a large number of TFTs are formed on a glass substrate having a large area exceeding the width of a linear laser beam. In particular, when the substrate constitutes a liquid crystal display, a large screen is expected to be required. However, the present invention enables the production. Thus, the present invention is industrially useful.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a laser irradiation apparatus according to a first embodiment, and is a top view.

FIG. 2 is a sectional view taken along a dotted line AA ′ in FIG.

FIG. 3 is a sectional view taken along a dotted line BB ′ in FIG. 1;

FIG. 4 is a configuration diagram of a laser irradiation unit 39.

FIG. 5 is a configuration diagram of a lens system.

6 is a configuration diagram of a lens system, and is a cross-sectional view along the optical path in FIG.

FIG. 7 is an explanatory diagram of a step of forming a crystalline silicon film in Example 2.

FIG. 8 is an explanatory diagram of a scanning path of a laser beam.

FIG. 9 is an explanatory view of dividing the substrate.

FIG. 10 is an explanatory diagram of a manufacturing process of a TFT of Example 3.

FIG. 11 is an explanatory diagram of a manufacturing process of the TFT of Example 3;

FIG. 12 is an explanatory diagram of a scanning path of a laser beam according to a fifth embodiment.

FIG. 13 is an explanatory diagram of a conventional laser beam shape and a scanning method thereof.

FIG. 14 is an explanatory diagram of a conventional laser beam shape and a scanning method thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Substrate 13 ... Substrate transfer chamber 17 ... Cartridge loading / unloading chamber 18 ... Heating chamber 19 ... Laser irradiation chamber 33 ... Robot arm 34 ... Alignment mechanism 36 ... Heating Means 37 ・ ・ ・ Stage 39 ・ ・ ・ Laser irradiation means 51 ・ ・ ・ Oscillator 54 ・ ・ ・ Amplifier 55 ・ ・ ・ Attenuation means 71 ・ ・ ・ Glass substrate 73 ・ ・ ・ Amorphous silicon film 75 ・ ・ ・ Crystallinity Silicon film 76 Crystalline silicon film 80, 90 Substrate 81, 91 Element fabrication area 82, 92 Linear laser beam 83A-83C, 85, 93A, 93B Scan Route

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[Procedure amendment]

[Submission date] January 18, 2001 (2001.1.1)
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Detailed description of the invention

[Correction method] Change

[Correction contents]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin film transistor (T) formed on a substrate having a non-single-crystal crystalline silicon film.
The present invention relates to a laser processing method and a laser processing apparatus used in a photo-annealing process related to the production of a semiconductor device such as FT).

[0002]

2. Description of the Related Art In recent years, studies have been made on an insulating gate type semiconductor device having a thin-film active layer (also called an active region) on an insulating substrate. In particular, a thin film gate transistor, a so-called thin film transistor (TFT), has been enthusiastically studied. These are classified into amorphous silicon TFTs and crystalline silicon TFTs depending on the material and crystal state of the semiconductor used. Although crystalline silicon is not single crystal, it is non-single crystal. Therefore, these are collectively referred to as non-single-crystal silicon TFTs.

Generally, the electric field mobility of a semiconductor in an amorphous state is small, and therefore, a TF which requires high-speed operation is required.
Not available for T. Further, in the case of amorphous silicon, the P-type electric field mobility is extremely small, so that a P-channel TFT (PMOS TFT) cannot be manufactured.
T) and complementary MOS circuit (CMOS)
Cannot be formed.

On the other hand, a crystalline semiconductor has a higher electric field mobility than an amorphous semiconductor, and therefore can operate at high speed. In crystalline silicon, not only NMOS TFTs but also PMOS TFTs can be obtained in the same manner.
An OS circuit can be formed.

A non-single-crystal crystalline silicon film is obtained by thermally annealing an amorphous silicon film obtained by a vapor deposition method at an appropriate temperature (usually 600 ° C. or higher) for a long time or by intense light such as laser. It was obtained by irradiation (light annealing).

However, when an inexpensive and highly processable glass substrate is used as the insulating substrate, a crystalline silicon film having a sufficiently high electric field mobility (high enough to form a CMOS circuit) can be formed only by thermal annealing. Getting it was extremely difficult. This is because the glass substrate as described above generally has a low strain point temperature (about 600 ° C.) and cannot raise the substrate temperature to a temperature necessary to obtain a crystalline silicon film having sufficiently high mobility. It is.

On the other hand, when optical annealing is used for crystallization of a silicon film based on a glass substrate, high energy can be applied only to the silicon film without increasing the temperature of the substrate so much. Therefore, it is considered that the optical annealing technique is very effective for crystallization of a silicon film based on a glass substrate.

At present, a high output pulse laser such as an excimer laser is most suitable as a light source for optical annealing. The maximum energy of this laser is much larger than that of a continuous wave laser such as an argon ion laser, and therefore, mass productivity can be further improved by using a large spot of several cm ² or more. However,
With a commonly used square or rectangular shaped beam, it is necessary to move the beam up, down, left and right to process one large area substrate, and there is still room for improvement in terms of mass productivity.

In this regard, the beam is deformed linearly,
Beam length (longitudinal size of linear beam cross section)
Can be greatly improved by making the length longer than the substrate to be processed and moving and scanning this beam relative to the substrate. Here, the scanning means that the linear laser is moved in the line width direction (the direction orthogonal to the longitudinal direction of the linear beam cross section) and the irradiation area is not divided.
Irradiation means overlapping. In general, when irradiating a linear laser beam over a large area, the scanning path is made parallel.

Further, by performing thermal annealing before optical annealing, a silicon film having higher crystallinity can be manufactured.
Regarding the method by thermal annealing, see JP-A-6-2441.
As described in No. 04, elements such as nickel, iron, cobalt, platinum and palladium (hereinafter referred to as crystallization catalyst elements or simply catalyst elements) utilize the effect of promoting the crystallization of amorphous silicon. Thus, a crystalline silicon film can be obtained by thermal annealing at a lower temperature and for a shorter time than usual.

[0011]

However, due to its maximum energy, the linear laser beam is irradiated with a linear laser beam whose length (the length of the laser beam cross section in the longitudinal direction) is long. Processing was limited to about 20 cm.

If the laser beam is processed to a longer length, the energy density of the laser beam becomes insufficient for crystallizing, for example, an amorphous silicon film. Therefore, when using a large-area substrate and performing laser processing on an area that exceeds the length of the linear laser, the scanning of the laser beam is performed in the vertical and horizontal directions, that is, in both the line width direction and the length direction. Had to be moved. FIG. 13 schematically shows a conventional laser beam scanning path.

FIG. 13A is a cross-sectional view of a linear laser beam, and FIG. 13B is a view of the irradiated surface viewed from above. As shown in FIG. 13A, the end 1a of the linear laser beam 1 is not a perfect rectangle, and the energy density in this portion is dispersed.

As shown in FIG. 13B, the linear laser beam 1 is scanned along two scanning paths 2 and 3. For example, the linear laser beam 1 is scanned on the left scanning path 2
Is scanned downward along the scanning path 3, and then scanned downward along the right scanning path 3. At this time, it is necessary to perform scanning so that the end portions 1a of the linear laser beam 1 overlap. However, how to overlap the end portions 1a of the linear laser beam 1 becomes a problem. In FIG. 13B, a region 4 indicated by a rectangle is a region where the region where the end 1a of the linear laser beam 1 overlaps on the irradiated surface is scanned.

However, since it is generally difficult to control the energy density at the end 1a of the linear laser beam 1, the semiconductor element manufactured in the region 4 and the vicinity thereof is smaller than the elements provided in other parts. , Characteristic variations were conspicuous. Therefore, the semiconductor material in the region 4 is not suitable for processing a semiconductor element.

As a countermeasure against the above problem, a laser beam is radiated through a slit to shield an end portion in a length direction in which energy density is difficult to control, thereby forming an end portion of the laser beam. . FIG. 14A is a cross-sectional view of a linear laser beam formed by a slit, and FIG. 14B is a schematic diagram of a scanning path of the laser beam, and is a diagram of a surface to be irradiated viewed from above. .

As shown in FIG. 13A, the end 5a of the laser beam 5 is formed into a rectangular shape by passing through a slit.
Due to the shaping, the energy density distribution at the end 5a becomes more uniform than the linear laser beam 1 in FIG.

As shown in FIG. 14B, when the linear laser beam 5 is irradiated, for example, the linear laser beam 5 is scanned downward along the left scanning path 6 and then to the right scanning path 7 To scan down along. At this time, the end 5a of the linear laser beam 5
Are scanned so as to overlap each other.
a is formed into a rectangular shape, since its energy density distribution uniform, as indicated by 8, the end portion 5 of the linear laser beam 5
a may be overlapped to the extent that the end portions 5a overlap.
Can be reduced.

However, even if the energy density of the end 5a of the laser beam 5 is controlled by using the slit, the characteristics of the semiconductor element formed in the scanned region 8 where the end 5a of the laser beam 5 overlaps still remain. Has a remarkable variation in characteristics as compared with devices manufactured in other regions.

An object of the present invention is to provide a laser processing method and a laser processing apparatus capable of solving the above-mentioned problems and performing a laser annealing step on a large-area semiconductor film at a high throughput.

Another object of the present invention is to provide a laser processing method and a laser processing apparatus for a semiconductor film having a large area, which can suppress variations in characteristics among a plurality of semiconductor elements.

[0022]

Means for Solving the Problems To solve the above problems, one of the constitutions of the present invention comprises a first and a second contacting each other.
2 are formed on the substrate, and the laser
The first element forming area along a first scanning path with laser light.
Scanning the area, and performing the second scanning with the laser light having a linear cross section.
Scanning the second element formation region along a path;
A first element substrate having one element formation region;
And a second element substrate having an element formation region of
A laser processing method for dividing, wherein the first scanning process is performed.
Path and the second scanning path overlap laser light
An area to be illuminated, the area being illuminated overlapping
Is characterized in that it is divided so as to be outside the element substrate.
This is a laser processing method.

In another embodiment of the present invention , a matrix is provided on a substrate.
Forming a plurality of element forming regions arranged in a shape,
The cross section is linear so that the element formation region has uniform characteristics.
Scanning the substrate with laser light,
One is a plurality of element substrates so as to include the element formation region.
And a plurality of thin film transistors are formed on the element substrate.
A laser processing method comprising:
Is a direction substantially perpendicular to the longitudinal direction of the cross section,
The longitudinal length of the cross section is larger than the width of the element forming region.
Is also a long laser processing method.

In another embodiment of the present invention, a laser beam is applied to a substrate.
Formed to have a long cross section in the width direction, and the length of the substrate
Moving the substrate in a direction to move a first region of the substrate forward.
Scan with the laser light, after scanning the first region, the
The laser light is applied to the substrate along the width direction of the substrate.
The substrate in the direction opposite to the length direction.
To move the laser light to the second region of the substrate.
A laser processing method for scanning, wherein the first area
Includes the entire first element formation region, and includes the second element formation region.
Region includes all of the second element formation region,
The cross-sectional width of the laser beam is shorter than the width of the substrate.
The width of the cross section of the laser beam is the first and the second.
The first element formation region being longer than the width of the element formation region;
And the second element formation region are separated from each other, and the laser
-The width of the cross section of the light is 10 to 30 cm
Laser processing method.

According to another structure of the present invention , a semiconductor substrate is mounted on a rectangular substrate.
A body film is formed, and the laser beam
And move the substrate in the length direction of the substrate
Scanning the first region of the semiconductor film,
After that, the substrate is moved relatively to the width direction of the substrate.
And moving the substrate in the direction opposite to the length direction to
Scanning a second region of the conductive film and etching the semiconductor film;
Laser processing method to form multiple active layers
Scanning the first area to obtain the first
Crystallizing an area and scanning the second area
To crystallize the second region,
The length is shorter than the cross-sectional width of the laser beam,
A region where the first region overlaps or touches the second region
Is removed during the etching and the width of the laser light
Is a laser processing characterized in that it is 10 to 30 cm.
It is a logical method.

In another embodiment of the present invention, the laser light is applied to the substrate.
Formed to have a long cross section in the width direction, and
Scanning the first area of the substrate by moving the substrate in the direction
After the scanning, move the substrate along the width direction,
The substrate is moved in a direction opposite to the length direction to
Scans a second area of the first area and the second area.
Dividing the substrate into at least two parts corresponding to the area
A laser processing method, wherein the dividing is performed in the first area.
In the area where the area overlaps with or touches the second area
The width of the laser light is 10 to 30 cm
It is a laser processing method characterized by the following.

According to another structure of the present invention , a semiconductor film is formed on a substrate.
Including a plurality of crystalline silicon from the semiconductor film
Form an active layer and apply laser light to the substrate in a cross section that is long in the width direction.
And moved in the length direction of the substrate to
Scanning a first region of the substrate, and after the scanning,
The substrate is moved in the width direction relative to the laser beam.
Moving the substrate in a direction opposite to the length direction.
A laser processing method for scanning a second area of the substrate.
Thus, the width of the laser light is shorter than the width of the substrate,
Scanning the first area to obtain the first area
Annealing the active layer formed in the second region
Before being formed in the second area by scanning
Annealing the active layer, wherein the active layer is in the first region
Is formed in a region where the second region overlaps or touches the second region.
The width of the laser light is 10-30cm
There is provided a laser processing method.

Another structure of the present invention has an element forming region.
Forming a semiconductor film on a substrate, and applying laser light to the substrate.
Formed to have a long cross section in the width direction, and hang vertically in the width direction.
The element formation region, which is a part of the semiconductor film in a vertical direction;
Scanning the area for the first time, and moving the substrate against the laser light.
A second scanning laser that moves relative to said portion
The processing method, wherein the width of the laser beam is set to
The width of the laser beam is shorter than the width of the element formation area.
The irradiation energy of the laser light longer than the width of the region
Indicates that the second scan is larger than the first scan,
The width of the light is 10 to 30 cm
This is a laser processing method.

In another embodiment of the invention, the laser beam is elongated.
Molded into a cross-section, and place the elongated
Moving the substrate in a direction perpendicular to the first direction,
Scans the first area in the direction opposite to the vertical direction.
Performing a second scan on the first area,
Moving the substrate relative to the laser light,
Moving the substrate in a vertical direction to a second region of the substrate;
Make a third scan through the area and move forward in a direction opposite to the vertical
The laser processing method for performing a fourth scan on the second area.
Thus, the second scan is more laser than the first scan.
-The irradiation energy of light is large, and the fourth scan is
The irradiation energy of the laser light is larger than the third scan.
The width of the laser beam is 10 to 30 cm
A laser processing method characterized by the following.

[0030]

The present invention scans a linear laser beam,
Laser irradiation is performed on the semiconductor film having a width larger than the cross-sectional length of the laser beam, and when annealing is performed, the end portions 1 of the laser beams 1 and 5 as shown in FIG.
A semiconductor element is not formed in a region irradiated with the overlapped portions a and 5a.

In other words, control is performed such that the region irradiated with the laser beam in the longitudinal direction overlapping or in contact with the laser beam is not located on the element region of the semiconductor film (the region where the semiconductor element is provided). And laser irradiation.

In this way, even if the substrate is enlarged and the region to be irradiated becomes large, laser annealing can be performed at a high throughput and variation in characteristics between semiconductor elements can be suppressed. .

[0033]

Embodiment 1 FIGS. 1 to 3 are configuration diagrams of a laser irradiation apparatus of the present embodiment, FIG. 1 is a top view, and FIG. 2 is a cross-sectional view taken along a dotted line AA ′ in FIG. FIG. 3 is a cross-sectional view taken along a dotted line BB ′ in FIG. The laser irradiation apparatus of this embodiment is a multi-chamber type apparatus, and is a single-wafer type apparatus capable of continuously processing many substrates (samples) one by one.

A large number of substrates 10 to be processed are stored in a cartridge 11, and the entire cartridge 11 is carried into the apparatus.

In a substrate transfer chamber 13 for transferring the substrate 10 in the apparatus, a cartridge loading / unloading chamber 17, a heating chamber 18, and a laser irradiation chamber 1 are operated by gate valves 14 to 15.
9 are connected to each other. Substrate transfer chamber 13, cartridge loading / unloading chamber 17, heating chamber 18, laser irradiation chamber 1
A gas supply system 20 to supply gas, an inert gas or the like is connected to the upper part, and an exhaust system 29 to 32 to which vacuum pumps 25 to 28 are connected. It is connected to the. Thereby, the substrate transfer chamber 13, the cartridge loading / unloading chamber 17, the heating chamber 1
8. The atmosphere, pressure and the like in the laser irradiation chamber 19 can be controlled.

A robot arm 33 is provided in the substrate transfer chamber 13.
Is provided, and the substrates 10 can be transferred one by one to the cartridge loading / unloading chamber 17, the laser irradiation chamber 19, or the heating chamber 18. Further, an alignment mechanism 34 is provided on the gate valve 14 side, and the substrate 10 and the robot arm 33 are aligned.

In the heating chamber 18, a large number of substrates 10 can be stored on an elevator 35, and the substrate 10 can be heated to a predetermined temperature by a heating means 36 composed of a resistor or the like.

The laser irradiation chamber 19 contains the substrate 10
Is provided on the stage 37. The stage 37 has a heating unit for heating the substrate 10,
In addition, a guide mechanism, a motor, and the like (not shown) make it possible to move horizontally in the two-dimensional direction in the plane of FIG. 1 and to rotate about an axis perpendicular to the plane of the paper. Further, on the upper surface of the laser irradiation chamber 19, there is provided a quartz window 38 into which laser light emitted from the outside of the apparatus enters.

As shown in FIG. 2, a laser irradiating means 39 is provided outside the apparatus, and a mirror 40 is disposed on an optical path 41 of the laser irradiating means 39 in a laser beam emitting direction. A quartz window 38 of the laser irradiation chamber 19 is provided on the light path 41 thus formed, and the laser light emitted from the laser irradiation means 39 is reflected by the mirror 40, passes through the quartz window 38, and is placed on the stage 37. Irradiated at 10.

FIG. 4 is a schematic structural view of the laser irradiation means 39. Total reflection mirrors 52 and 53 are arranged on an optical path 50 in the emission direction of an oscillator 51 for oscillating a laser.
An amplifier 5 is provided on the optical path 50 in the reflection direction of the total reflection mirror 53.
4. Attenuating means 5 composed of a plurality of filters 55a to 55d
5. An optical system 56 for forming a laser beam into a linear shape is sequentially arranged.

The attenuating means 55 is for adjusting the laser energy, and the filters 55a to 55d have the function of attenuating the energy of the transmitted light, and their transmittances are different from each other. Filters 55a-5
The transmittance of 5d was 96%, 92%, 85%, and 77%, respectively.
%. These filters 55a to 55d can be inserted and removed independently from the optical path 50 by driving means such as an electromagnet and a motor (not shown). By appropriately combining the filters 55a to 55d, a filter having a transmittance of 57 to 96% can be formed. For example, a filter 55a having a transmittance of 96% and a neutral density filter 55b having a transmittance of 92%
By combining the above, a neutral density filter having a transmittance of 88% can be obtained.

The filters 55a to 55d are made by alternately coating quartz with hafnium oxide and silicon dioxide in layers, and the transmittance of the neutral density filters 55a to 55d depends on the number of coated layers. In this embodiment, the number of filters 55a to 55d of the attenuation means 55 is set to 4
The number of filters is not limited to this number, and the number of filters and the transmittance thereof may be determined so that laser energy can be appropriately adjusted.

FIGS. 5 and 6 are diagrams showing the construction of the optical system 56.
FIG. 6 corresponds to a cross-sectional view along the optical path 50 of FIG. As shown in FIGS. 5 and 6, on the optical path 50, in order from the incident direction, a cylindrical concave lens 61, a cylindrical convex lens 62, fly-eye lenses 63 and 64 having axes perpendicular to each other, cylindrical convex lenses 65 and 66,
The total reflection mirror 67 is arranged, and a cylindrical lens 68 is disposed on the optical path in the reflection direction of the total reflection mirror 67.

In the laser irradiation means 39 shown in FIG. 4, the laser light oscillated by the oscillator 51 is reflected by total reflection mirrors 52 and 53, respectively, and is incident on the amplifier 54. The laser light is amplified by the amplifier 54 and reflected by the total reflection mirrors 55 and 56, respectively.
5, the light reaches the optical system 56, and passes through the cylindrical concave lens 61, the cylindrical convex lens 62, and the fly-eye lenses 63 and 64 as shown in FIGS. It is changed to a shape distribution. Further, the cylindrical convex lens 6
5 and 66, reflected by the total reflection mirror 67,
The light is converged by the cylindrical lens 68 and formed into a linear beam image at the focal plane f. This linear beam image has a longitudinal direction in a direction perpendicular to the paper surface in FIG.

The shape of the laser beam is a rectangle of about 3 × 2 cm ² immediately before entering the optical system 56.
After that, it is formed into an elongated linear beam having a width of about 10 to 30 cm and a width of about 0.1 to 1 cm.

When performing laser annealing with the laser irradiation apparatus shown in FIGS. 1 to 3, first, the gate valves 14 to 16 are closed, and the substrate transfer chamber 13, the laser irradiation chamber 19, and the heating chamber 18 are nitrogen-filled. Fill with gas.

Next, the cartridge 11 containing a large number of the substrates 10 is loaded into the cartridge loading / unloading chamber 17 from outside. A door (not shown) is provided in the cartridge loading / unloading chamber 17, and by opening and closing the door,
Carry in / out of the cartridge 11 is performed. Cartridge 1
After loading the cartridge 1 into the cartridge loading / unloading chamber 17, the door is closed, the cartridge loading / unloading chamber 17 is closed, nitrogen gas is supplied from the gas supply system 21, and the cartridge loading / unloading chamber 17 is filled with nitrogen gas. Let it. It should be noted that the cartridge loading / unloading chamber 17 is not in a depressurized state but is in an atmospheric pressure state. Next, the gate valve 14 and the gate valve 15 are opened. The gate valve 14 may be kept open until a series of steps is completed.

The substrates 10 are taken out one by one from the cartridges 11 installed in the cartridge loading / unloading chamber 17 by the robot arm 33, placed on the alignment mechanism 34, and the positions of the robot arms 33 and the substrates 10 are once aligned. Thereafter, the substrate 10 is picked up again by the robot arm 33 and transferred to the heating chamber 18. Substrate 1 in heating chamber 18
Every time 0 is transferred, the elevator 35 is raised or lowered, and the substrates 10 are stored in a state of being sequentially stacked.

After a predetermined number of substrates 10 have been carried in the heating chamber 18, the gate valve 15 is closed and the heating means 3
The substrate 10 is heated by 6. When the substrate 10 is heated to a predetermined temperature, the gate valve 15 is opened, and the substrate 10 is transferred from the heating chamber 18 to the substrate transfer chamber 13 by the robot arm 33, placed on the alignment mechanism 34, and positioned again. Is performed.

When the gate valve 16 is opened, the substrate 10 on the alignment mechanism 34 is
Is placed on the stage 37 of the laser irradiation chamber 19, and the gate valve 15 and the gate valve 16 are closed. The gate valve 15 is preferably opened and closed each time the substrate is unloaded. This is to prevent the atmosphere of the heating chamber 18 from thermally affecting the mechanical configuration of the robot arm 33 and the like.

After closing the gate valve 16, a linear beam is emitted from the laser irradiating means 39, and the linear laser irradiates the substrate 10 on the stage 37 through the mirror 40 and the quartz window 38. When the stage 37 rotates and moves horizontally, the substrate 10 is irradiated with a linear laser along a predetermined scanning path. During irradiation with laser light,
The substrate 10 is heated to the same temperature as the temperature in the heating chamber 18 by the heating means provided on the stage 37, and thermal fluctuation is suppressed. When the laser beam irradiation is completed,
The gate valve 16 is opened, and the substrate 10 is stored in the cartridge 11 in the cartridge loading / unloading chamber 17 by the robot arm 33. Thus, the processing for one substrate 10 is completed.

When the processing of one substrate 10 is completed, the gate valve 15 is opened, and the next substrate 10 is taken out of the heating chamber 18 by the robot arm 33 and transferred to the laser irradiation chamber 19, where the stage 37 is moved. Placed on the
Laser light is applied. In this manner, the substrate 10 accommodated in the heating chamber 404 is irradiated with the laser light one by one. When all processes are completed, the processed substrate 1
0 are all stored in the cartridge 11 installed in the cartridge loading / unloading chamber 17. The cartridge 11 may be taken out of the cartridge loading / unloading chamber 17 and then proceed to the next step.

The heating temperature in the heating chamber 18 needs to be lower than the temperature at which the amorphous silicon film is crystallized. This is because the time in the heating chamber differs depending on the substrate 10. Generally, the heating temperature in the heating chamber 18 is 2
It is selected to be about 00 to 400 ° C. The heating temperature needs to be the same as the heating temperature of the substrate 10 when the laser beam is irradiated.

Embodiment 2 In this embodiment, an example is described in which a crystalline silicon film for manufacturing a semiconductor element is manufactured using a substrate having a size exceeding the width of a linear laser beam. FIG. 7 shows a manufacturing process diagram of the crystalline silicon film.

As shown in FIG. 7A, the glass substrate 71
(In this embodiment, a 360 mm × 460 mm Corning 7)
059), a silicon oxide film serving as a base film 72 having a thickness of 2000 ° and an amorphous silicon film 73 having a thickness of 500 ° were continuously formed by a plasma CVD method.

Then, 10 ppm was obtained by spin coating.
Was applied to the surface of the amorphous silicon film 73 and dried to form a nickel layer 74. It was better to add a surfactant to the aqueous nickel acetate solution. Since the nickel layer 74 is extremely thin, it does not always have a film shape, but does not cause any problem in the subsequent steps.

As shown in FIG. 7B, the amorphous silicon film 73 is crystallized by performing thermal annealing at 550 ° C. for 4 hours to obtain a crystalline silicon film 75. By the heating, nickel in the nickel layer 74 plays a role of a crystal nucleus, and promotes crystallization of the amorphous silicon film 73. Therefore, the crystalline silicon film 75 can be obtained at a low temperature of 550 ° C. for 4 hours (strain point temperature of Corning 7059 or less) and in a short time.

The catalyst in the crystalline silicon film 75
Element concentration is 1 × 10^Fifteen~ 1 × 10¹⁹Atom / cm^ThreeIn
I liked it. 1 × 10^FifteenAtom / cm^ThreeAt the following concentrations
If so, it is difficult to obtain a catalytic effect that promotes crystallization
Becomes 1 × 10¹⁹Atom / cm ^ThreeAt higher concentrations above,
The metallic properties appear in the capacitors, and the semiconductor properties disappear.
To do so. In this embodiment, the crystalline silicon film 7
The concentration of the catalyst element in 5 was 1 × 10 at the minimum value in the film.
¹⁷~ 5 × 10¹⁸Atom / cm^ThreeMet. Note that these values
Is analyzed and measured by secondary ion mass spectrometry (SIMS).
Specified.

In order to further enhance the crystallinity of the crystalline silicon film 75 thus obtained, as shown in FIG. 7C, the film 75 is irradiated with an excimer laser which is a high-power pulse laser. Then, a crystalline silicon film 76 having better crystallinity is formed.

When irradiating with a laser,
Using a KrF excimer laser (wavelength 24
8 nm, pulse width 30 nsec) 1 mm x 185 mm
LinearlyMoldingFirst, 220mJ / cm^TwoDegree of energy
Irradiate the laser beam with energy and then the laser energy
Lug density of 100mJ / cm^Two~ 500mJ / cm ^Two
In the range of, for example, 370 mJ / cm^TwoIrradiation. Ma
Also, when focusing on one point of the irradiation target, 2 to 20 shots
Laser beam scanning so that laser light is irradiated
The speed, in fact, the movement of the stage 37 on which the substrate 71 is placed
Adjust the moving speed.

The laser energy of 220 mJ /
Switching from cm ² to 370 mJ / cm ² is performed by using the laser irradiation means 39 shown in FIG.
This is performed by selectively inserting and retracting 55d into the optical path 50. The substrate temperature during laser irradiation is 200 ° C.
And

The method of irradiating by changing the irradiation energy in this way is called multi-step irradiation. In the case of this embodiment, the irradiation is performed twice, so that the irradiation is performed in two stages. With the two-step irradiation, the crystalline silicon film 76 can be formed more than in the one-step irradiation.
Can be further improved in crystallinity. In the case of one-step irradiation, the energy density of the laser should be 10
Irradiation may be performed in the range of 0 mJ / cm ^{2 to} 500 mJ / cm ² , for example, at 370 mJ / cm ² .

FIGS. 8A to 8D show the scanning path of the laser beam of this embodiment. As shown in FIGS. 8A to 8D, on a surface to be irradiated on the substrate 80, rectangular element manufacturing regions 81 in which thin film transistors are manufactured are arranged in a 2 × 2 matrix. Therefore, a semiconductor element is manufactured using only the crystalline silicon 76 in the element manufacturing area 81 on the glass substrate 71 shown in FIG. 7C. The substrate 80 on which the semiconductor element is manufactured is divided into four element substrates 86A to 86D as shown in FIG.

Further, as shown in FIG. 9, it is premised that the substrate 80 is cut to a length equal to or less than the length of the linear laser beam after the semiconductor device is manufactured. The length L of the linear laser beam 82 in the longitudinal direction is set so that the region 4 or 8 where the end portions in the longitudinal direction are overlapped and irradiated is outside the device manufacturing region 81.
Is longer than the width W of the element manufacturing region 81.

FIG. 8A shows a two-stage irradiation.
As shown in (C), the scanning paths 83a to 83c are set so as to draw a linear stroke in parallel so that the linear laser beam 82 is irradiated twice to each of the element manufacturing regions 81. In the case of one-step irradiation, for example, as shown in FIG.
Further, the scanning paths 83a to 83c and 85 have a uniform direction with respect to all the element manufacturing regions 80 on the same substrate 80.

In order to scan the linear laser beam 83 along the scanning path shown in FIGS. 8A to 8C or 8D,
Irradiation may be performed while moving the linear laser beam 82 relative to the irradiated surface 80 along a direction substantially orthogonal to the longitudinal direction. Instead of actually moving the laser beam 82, in the laser irradiation apparatus shown in FIGS.
The substrate 80 having the surface to be irradiated is moved so that the linear laser beam 82 is scanned along the scanning path 83a, 83b or 83c.

In this embodiment, since the width W of the element forming region 81 is shorter than the length L of the linear laser beam 82, the end of the linear laser beam 82 does not scan the element forming region 81. Therefore, the film quality of the obtained crystalline silicon film 76 can be made uniform, so that the element fabrication region 81
The characteristics of the semiconductor element manufactured in the above can be made uniform. Further, by processing a large-area substrate 80, a large number of substrates on which semiconductor elements having the same characteristics are formed can be produced in one process, so that the throughput can be improved.

[Embodiment 3] In this embodiment, a process of manufacturing a thin film transistor for driving a pixel of a liquid crystal display using the crystalline silicon film 76 obtained in Embodiment 2 will be described. 10 and 11 show a manufacturing process of the thin film transistor of this embodiment.

As shown in FIG. 10A, the glass substrate 1
01, a silicon oxide film as a base film 102 is 3000
A crystalline silicon film 103 is deposited to a thickness of Å by a plasma CVD method or a low pressure thermal CVD method, and a crystalline silicon film 103 obtained by crystallizing an amorphous silicon film in accordance with the crystallization step described in the second embodiment is formed on the surface of the base film 102. Is formed.

Next, as shown in FIG. 10B, the crystalline silicon film 103 is etched into an island shape to form an element fabrication region 1.
A large number of active layers 104 are formed at predetermined positions in the area 00. In this embodiment, as shown in FIGS. 8 and 9, a thin film transistor is formed on the glass substrate 101 in order to divide the glass substrate 101 into four and obtain four identical element substrates. Rectangular element fabrication region 100
They are arranged in a × 2 matrix. Device fabrication area 1
A large number of active layers 104 are formed at predetermined positions in the area 00. Therefore, when the crystalline silicon film 103 is obtained, the end of the linear laser beam is prevented from passing through the inside of the element manufacturing region 100.

Next, the silicon oxide film 105 constituting the gate insulating film is formed in a thickness of 1000 to 1500 by the plasma CVD method.
Then, an aluminum film constituting the gate electrode 106 is deposited to a thickness of 5000 mm by sputtering. If scandium is previously contained in aluminum in an amount of 0.2% by weight, generation of hillocks and whiskers in a subsequent heating step or the like can be suppressed.

Next, the surface of the aluminum film is anodized to form a very thin dense anodic oxide (not shown). Next, a resist mask 107 is formed on the surface of the aluminum film. At this time, since a dense anodic oxide (not shown) is formed on the surface of the aluminum film, it can be formed by closely attaching the resist mask 107. Then, the aluminum film is etched using the resist mask 107 to form the gate electrode 106.

As shown in FIG. 10C, with the resist mask 107 left, the gate electrode 106 is anodized to form a porous anodic oxide 108 to a thickness of 4000 °. At this time, since the resist mask 107 is in close contact with the surface of the gate electrode 106, the porous anodic oxide 108 is formed only on the side surface of the gate electrode 106.

Next, as shown in FIG. 10C, after the resist mask 107 is peeled off, the gate electrode 106 is anodized again in an electrolytic solution to form the dense anodic oxide 10.
9 is formed to a thickness of 1000 °.

The formation of the anodic oxide may be changed by changing the electrolytic solution to be used. When the porous anodic oxide 108 is formed, citric acid, oxalic acid, chromic acid or sulfuric acid is used.
An acidic solution containing 酸性 20% may be used. On the other hand, when the dense anodic oxide 109 is formed, an electrolytic solution in which an ethylene glycol solution containing tartaric acid, boric acid, or nitric acid at 3 to 10% and the pH is adjusted to about 7 may be used.

As shown in FIG. 11A, the gate electrode 1
The gate insulating film 110 is formed by etching the silicon oxide film 105 using the porous anodic oxide 106 and the surrounding porous anodic oxide 108 and the dense anodic oxide 109 as a mask.

As shown in FIG. 11D, after removing the porous anodic oxide 108, the gate electrode 106, the dense anodic oxide 109, and the gate insulating film 110 are masked by ion doping. Then, impurities are implanted into the active layer 104. In this embodiment, in order to form a P-channel TFT, phosphine (PH) is used as a doping gas.
₃ ) Doping with phosphorus ions. At the time of doping, conditions such as a dose and an acceleration voltage are controlled so that the gate insulating film 110 functions as a semi-transparent mask.

As a result of doping, phosphorus ions are implanted at a high concentration in the region not covered with the gate insulating film 110,
A source region 111 and a drain region 112 are formed.
Further, low-concentration impurity regions 113 and 114 are formed by implanting low-concentration phosphorus ions into a region covered only by the gate insulating film 110. Since no impurity is implanted into the region immediately below the gate electrode 106, the channel region 1
15 are formed.

Since the low-concentration impurity regions 113 and 114 function as high-resistance regions, they contribute to a reduction in off-state current.
In particular, the low concentration impurity region 113 on the drain region 112 side
Is called LDD. In addition, dense anodic oxide 10
9 is sufficiently thick so that a dense anodic oxide 10
9 can be set as the offset region, and the off-state current can be further reduced.

After the doping step, laser annealing is performed in the laser irradiation apparatus shown in FIGS. 1 to 3 to activate the doped phosphorus ions. The annealing condition at this time is that the energy density of the laser is 100 mJ.
/ Cm ^{2 to} 350 mJ / cm ² , for example, 16
0 mJ / cm ^2, and when focusing on an arbitrary point on the irradiated surface, a linear laser beam of 20 to 40 shots is irradiated, and the substrate temperature is kept at 200 ° C. In addition, the linear laser beam for one-stage irradiation is shown in FIG.
Scanning may be performed in accordance with the scanning path 85 shown in FIG. 9D. At this time, the end of the linear laser beam is
Do not pass through zero.

After the laser annealing, thermal annealing may be performed. In this case, heating may be performed at a temperature of 450 ° C. for about 2 hours.

As shown in FIG. 11C, the plasma CV
According to the D method, a silicon oxide film is
A film is formed to a thickness of 00 °. Note that as the interlayer insulator 116, instead of a single-layer film of a silicon oxide film, a single-layer film of a silicon nitride film or a stacked film of a silicon oxide film and a silicon nitride film may be formed. Next, a contact hole is formed in each of the source region 111 and the drain region 112 by etching the interlayer insulator 116 made of a silicon oxide film by a known etching method.

Next, an aluminum film is formed to a thickness of 4000 ° by a sputtering method, and is patterned to form an electrode 117118 connected to the source region 111 and the drain region 112.
19, a silicon nitride film is formed, and the passivation film 1 is formed.
19, a contact hole for the electrode 118 on the drain region 112 side is formed. Next, an ITO film is formed and patterned to form a pixel electrode 120 in a contact hole connected to the electrode.

Through the above steps, a TFT having an LDD structure is manufactured in the element manufacturing region 100 on the glass substrate 101. Lastly, as shown in FIG. 9, the substrate 101 is divided into element forming regions 100, whereby four panels of a liquid crystal display device can be obtained.

In this embodiment, the manufacturing process of an N-channel thin film transistor for driving a pixel of a liquid crystal display device has been described. However, a thin film transistor constituting a peripheral driving circuit and a pixel in one element manufacturing region 100 are described. May be formed at the same time. In this case, the conductivity type of the thin film transistor is controlled by using a known CMOS technology so that the thin film transistor constituting the peripheral driver circuit is a complementary thin film transistor including an N-channel thin film transistor and a P-channel thin film transistor. I just need.

[Embodiment 4] This embodiment relates to a scanning path of a laser beam when a substrate is not divided. In this case, as shown in FIGS. 13 and 14, the region 4 where the ends of the linear laser beam overlap or the region 8 in contact with the linear laser beam may be arranged in the element fabrication region. In such a case, regions 4 and 8 shown in FIGS.
The semiconductor element may be arranged so that the semiconductor element does not straddle (is not located or not approached).

For example, in FIG. 10, the active layer 104 of the thin film transistor is not overlapped with these regions 4 or 8 so that the linear laser beam passes through the region 200 where the active layer 104 is not formed. What is necessary is just to adjust the length of a shape beam.

A portion (seam portion) where the end portions in the length direction of the linear laser beam are overlapped and irradiated is shown in FIG.
Whether they overlap to some extent as in the region 4 of FIG. 3 or contact only as in the region 8 in FIG. 14 depends on the density of the semiconductor elements on the substrate.

If the distance between the semiconductor elements is on the order of millimeters, the shape of the end of the linear laser beam, that is, the energy density distribution at the end does not matter.
As shown in (A), the end 1a of the linear laser beam 1 is
It is possible to irradiate a linear laser beam without molding . However, when the distance between the semiconductor elements becomes less than the millimeter order, as shown in FIG. 14 (A), a linear laser beam is formed by a slit, and the end is made rectangular, and further, as shown in FIG. It is necessary to scan so that the ends of the shaped laser beam are in contact.

Further, when the distance between the semiconductor elements is on the order of several microns, even if a linear laser is scanned as shown in FIG. There is a possibility that an element may be formed in the area 8 where the end 5a of the laser beam 5 has passed, and it is difficult to manufacture the element while avoiding the area where the end 5a of the laser beam 5 has passed.

In the case of manufacturing a liquid crystal display panel as a semiconductor element, for example, the interval between thin film transistors provided as a semiconductor element formed on the substrate is about 10 μm to 100 μm. Therefore, in this case, the linear laser beam is scanned so that the joint of the linear laser beam, that is, the end of the beam is in contact with the linear laser beam by cutting the end in the length direction using the slit. In this case, the seam portion is 10 to 20
If they are closely contacted with an accuracy of about μm, the accuracy is sufficient, and a liquid crystal display panel can be manufactured without forming a semiconductor element at the joint.

Embodiment 5 Embodiment 2 as shown in FIG.
In the figure, the element manufacturing regions 81 are arranged in a 2 × 2 matrix on the substrate 80. In order to uniformly irradiate the laser to the element manufacturing region, the element manufacturing region is preferably arranged symmetrically with respect to the substrate.
It is preferable to arrange them in a matrix of × 2n (n is a natural number of 1 or more). In this embodiment, as shown in FIG. 12, by using a substrate having a larger area, a 4 × 4 element manufacturing region 91 is arranged on a substrate 90, and one substrate is formed in one process. From 90, 16 substrates on which semiconductor elements having the same characteristics are manufactured are obtained.

To irradiate the linear laser beam 92 in two stages, for example, as shown in FIGS.
3A and 93B may be set. The length L of the linear laser beam 92 in the longitudinal direction is longer than the width W of the element manufacturing region 91 so that the linear laser beam 93 is uniformly irradiated. The region where the portions are overlapped and irradiated is set outside the element manufacturing region 91.

[0094]

According to the present invention, a laser annealing step for a semiconductor material having a large area can be performed at a high throughput. Further, according to the present invention, it was possible to suppress variation in characteristics among a plurality of semiconductor elements formed by laser annealing of a large-area semiconductor film.

The present invention is effective when a large number of TFTs are formed on a glass substrate having a large area exceeding the width of a linear laser beam. In particular, when the substrate constitutes a liquid crystal display, a large screen is expected to be required. However, the present invention enables the production. Thus, the present invention is industrially useful.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/336

Claims (21)

[Claims] A first element forming region that is in contact with each other is formed on a substrate, and the first element forming region is scanned along a first scanning path with a laser beam having a linear cross section. Scanning the second element formation region along a second scanning path with a laser beam having a linear cross section; a first element substrate having the first element formation region; and the second element A laser processing method for dividing the substrate into a second element substrate having a formation region and a region where laser light is overlapped and irradiated by the first scanning path and the second scanning path. The laser processing method according to claim 1, wherein the overlapping irradiation area is divided so as to be outside the element substrate. 2. The laser processing method according to claim 1, wherein the first scanning path and the second scanning path are parallel. 3. The device according to claim 1, wherein the first and second scanning paths are substantially orthogonal to a longitudinal direction of a cross section of the laser light, and a width of the cross section of the laser light is equal to a width of the element forming region. A laser processing method characterized by being longer than the width of the laser. 4. The laser processing method according to claim 1, wherein said scanning crystallizes a silicon film in said element formation region. 5. The method according to claim 1, wherein the scanning is performed by repeatedly passing through the first and second scanning paths, and the laser irradiation of the first and second scanning paths is performed. A laser processing method, wherein the energy is different. 6. The laser processing method according to claim 1, wherein the scanning path is set so as to draw a single stroke. 7. A plurality of element formation regions arranged in a matrix on a substrate, and the substrate is scanned with a laser beam having a linear cross section so that the plurality of element formation regions have uniform characteristics. A laser processing method of dividing at least one substrate into a plurality of element substrates so as to include the element formation region, and forming a plurality of thin film transistors on the element substrate, wherein the scanning direction is a length of the cross section. A laser processing method, wherein the length of the laser light in the longitudinal direction is longer than the width of the element formation region. 8. The laser processing method according to claim 7, wherein a width of the element substrate is equal to or smaller than a width of a cross section of the laser beam. 9. The laser processing method according to claim 7, wherein a peripheral driving circuit is formed in the element formation region. 10. The laser processing method according to claim 7, wherein the dividing is performed after forming the thin film transistor. 11. Forming a laser beam into a long cross section in the width direction of the substrate, moving the substrate in the length direction of the substrate, scanning a first region of the substrate with the laser beam, After scanning the first region, the laser light is moved relatively to the substrate along the width direction of the substrate, and the substrate is moved in a direction opposite to the length direction to move the laser light. A laser processing method for scanning a second region with the laser light, wherein the first region includes the entire first element formation region, and the second region includes the second region. All of the element formation regions are included, the width of the cross section of the laser light is shorter than the width of the substrate, the width of the cross section of the laser light is longer than the width of the first and second element formation regions, The first element formation region is separated from the second element formation region. And the width of the cross section of the laser beam, a laser processing method which is a 10 to 30 cm. 12. A semiconductor film is formed on a rectangular substrate, a laser beam is formed so as to have a cross section that is long in the width direction of the substrate, and the substrate is moved in the longitudinal direction of the substrate to form a semiconductor film. Scanning the first area, and after the scanning, the substrate is moved relative to the width direction of the substrate, and the substrate is moved in a direction opposite to the length direction to form a second area of the semiconductor film. A laser processing method for forming a plurality of active layers by etching the semiconductor film by scanning, wherein the first area is crystallized by scanning the first area, and the second area is scanned. The second region is crystallized, the length of the cross section of the laser beam is shorter than the width of the cross section of the laser beam, and the region where the first region and the second region overlap or touch each other. Is removed during the etching, A laser processing method, wherein the width of the laser beam is 10 to 30 cm. 13. A laser beam is formed so as to have a long cross section in the width direction of the substrate, and the substrate is moved in the length direction of the substrate to form a first section of the substrate.
Scanning the area of the substrate, after the scanning, moving the substrate along the width direction, moving the substrate in a direction opposite to the length direction to scan a second area of the substrate, A laser processing method for dividing the substrate into at least two portions corresponding to the first region and the second region, wherein the first region and the second region overlap each other. The laser processing method is performed along a portion or a contact portion, and a width of the laser beam is 10 to 30 cm. 14. A semiconductor film is formed on a substrate, an active layer containing a plurality of crystalline silicon is formed from the semiconductor film, and a laser beam is formed to have a long cross section in a width direction of the substrate. Scanning the first region of the substrate by moving the substrate in the length direction, and after the scanning, moving the substrate relative to the laser light in the width direction of the substrate; Is a laser processing method of scanning a second region of the substrate by moving in a reverse direction, wherein a width of the laser beam is shorter than a width of the substrate, and the first region is scanned by scanning the first region. Annealing the active layer formed in the first area, annealing the active layer formed in the second area by scanning the second area, the active layer comprises: An area overlaps with the second area; Not formed in the contact region, the width of the laser beam, a laser processing method which is a 10 to 30 cm. 15. The device according to claim 11, 12 or 13, wherein the first region and the second region have a thickness of 10 to 20 μm.
A laser processing method characterized by overlapping in the range of. 16. The laser beam according to claim 11, 12 or 13, wherein the laser beam is shaped by an optical system so as to have a long cross section in the width direction of the substrate, and after the shaping, passes through a slit. A laser processing method characterized in that an end portion of a cross section is shielded from light. 17. The laser processing method according to claim 12, wherein the semiconductor film is heated before irradiating the laser light. 18. The laser processing method according to claim 14, wherein an impurity is implanted into the active layer before irradiating the laser light. 19. The substrate according to claim 14, wherein the substrate is divided into at least two portions corresponding to the first region and the second region, and the division is performed by the first region and the second region. A laser processing method, which is performed along a region where the region overlaps or is in contact with the region. 20. A semiconductor film is formed on a substrate having an element formation region, and a laser beam is formed so as to have a long cross section in the width direction of the substrate, and a part of the semiconductor film is formed in a direction perpendicular to the width direction. A first scanning of the element forming region, and a second scanning of the part by moving the substrate relative to the laser light, wherein the width of the laser light is: The width of the laser beam is shorter than the width of the element formation region, the irradiation energy of the laser beam is larger in the second scan than in the first scan, A laser processing method, wherein the width is 10 to 30 cm. 21. A laser beam is shaped so as to have an elongated cross section, and the substrate is moved to a rectangular substrate in a direction perpendicular to the elongated direction to perform a first scan on a first region of the substrate. Performing a second scan of the first region in a direction opposite to the perpendicular direction, relative to the laser light in the elongated direction, and moving the substrate in the perpendicular direction. To move the second
A third scanning of an area of the second area, and a fourth scanning of the second area in a direction opposite to the vertical direction, wherein the second scanning is the first scanning. The laser processing is characterized in that the irradiation energy of the laser light is larger, the irradiation energy of the laser light is larger in the fourth scan than in the third scan, and the width of the laser light is 10 to 30. Method.