JP2000058835A - Thin film transistor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a semiconductor film having uniform film quality. SOLUTION: A semiconductor film having uniform film quality is formed by a first process where the semiconductor film is formed on a substrate 100; a second process where a laser beam whose total energy is not less than 5J and whose pulse width is not less than 100 nsec is radiated for one shot or a plurality of shots, and a high crystallized semiconductor film is formed, and a third process where the relative position of the semiconductor film and the laser beam is changed and the second process is repeated in a part different from a part of the semiconductor film. A thin film transistor having the semiconductor film and an active layer has a high characteristic without dispersion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates to a method for polycrystallizing an amorphous semiconductor film using laser light. Further, the present invention relates to a method for improving crystallinity of a polycrystalline semiconductor film using laser light. Further, the present invention relates to a thin film transistor using a polycrystalline semiconductor film obtained by these methods as an active layer. Further, the present invention relates to a semiconductor device using the thin film transistor.

[0003]

[Prior art]

In recent years, active research has been made on lowering the temperature of the manufacturing process of semiconductor elements, particularly thin film transistors (hereinafter referred to as TFTs). The main reason is that TF is placed on an insulated substrate such as glass, which is inexpensive and highly processable.
This is because it is necessary to form T. Further, from the viewpoint of miniaturizing elements and increasing the number of layers of elements, there is a demand for lowering the temperature of the TFT manufacturing process.

[0005] In a process for manufacturing a high-performance TFT, a step of crystallizing an amorphous component or an amorphous semiconductor material contained in the semiconductor material is required. Conventionally, thermal annealing (thermal annealing) has been used for such a purpose. In the case where silicon is used as a semiconductor material, 0.1 to 48 at a temperature of 600 ° C. to 1100 ° C.
Annealing for hours or longer has resulted in polyamorphous crystallization.

[0006] Generally, the higher the temperature, the shorter the processing time is required for the above-mentioned thermal annealing, but it has little effect at a temperature of 500 ° C or lower. Therefore, from the viewpoint of lowering the temperature of the manufacturing process, it has been necessary to replace the step performed by thermal annealing with another means. In particular, when a glass substrate is used as the substrate, since the heat resistance temperature of the glass substrate is about 600 ° C., a means equivalent to the above-described thermal annealing at a temperature lower than this temperature is required.

[0007]

[Problems to be solved by the invention]

Recently, as a method for satisfying the above-mentioned requirements, attention has been paid to polymorphization of an amorphous material by irradiating a semiconductor material with a laser beam. In thermal annealing by laser light irradiation, high energy comparable to thermal annealing can be applied only to desired locations, so that there is an advantage that it is not necessary to expose the entire substrate to high temperatures.

Regarding the irradiation of laser light, there are roughly two methods proposed.

The first method uses a continuous wave laser such as an argon ion laser, and irradiates a semiconductor material with a spot beam. This is a method in which the semiconductor material is polycrystallized by utilizing the difference in energy distribution inside the beam and the gradual solidification of the semiconductor material after melting due to the movement of the beam.

A second method uses a pulsed laser such as an excimer laser to irradiate a semiconductor material with a high energy laser pulse. At this time, the semiconductor material is instantaneously melted and solidified, whereby crystal growth proceeds. It is a method that utilizes that.

The problem with the first method is that the processing takes time. This is because the maximum energy of the continuous wave laser is limited, and the size of the beam spot is at most a mm square unit.

In the second method, an attempt is made to adopt a method in which the shape of the laser light is linearly deformed so as to have a length exceeding the substrate to be processed, and the laser light is relatively scanned with respect to the substrate. Has been made. By adopting such a method, the throughput can be greatly improved. The term "scanning" as used herein refers to irradiating a linear laser while overlapping it while shifting it slightly.

However, according to the above-described technique of irradiating the linear pulse lasers while shifting them little by little, linear stripes are inevitably generated on the surface of the semiconductor material irradiated with the laser. These stripes have a significant adverse effect on the characteristics of devices formed on semiconductor materials or devices formed in the future. This is a serious problem particularly when a plurality of devices are formed on a substrate and the characteristics of each of the devices must be made uniform. In such a case, although the characteristics are uniform in each of the stripe patterns, the characteristics of the stripes vary.

As described above, even in the annealing method using a linear laser beam, uniformity of the irradiation effect poses a problem. High uniformity here means that the same element characteristics are obtained regardless of where the element is formed on the substrate. To increase the uniformity means to make the crystallinity of the semiconductor material uniform.

Accordingly, a high-output excimer laser capable of annealing a large area with a single shot has recently been developed. By using this high-output excimer laser, large-area amorphous silicon can be polycrystallized at once. It has been found that the film quality of the polycrystallized silicon film is also uniform to some extent in the plane.

Here, as a conventional example, FIG. 35 shows a schematic top view in the case where this high-output excimer laser is used for manufacturing an active matrix substrate of an active matrix type liquid crystal display device.

In FIG. 35, reference numeral 3500 denotes a substrate.
3501 and 3505 are active matrix circuits. 3502 and 3505 are source driver circuits, and 3503, 3504, 3507 and 3508 are gate driver circuits. Reference numerals 3509 to 3512 denote irradiation regions of high-power excimer laser light, and the amorphous silicon film in each region is polycrystallized by one shot or a plurality of shots of laser light. Therefore, in this conventional example, the laser light is applied to the entire amorphous silicon film on the entire substrate by three times of relative movement of the laser light with respect to the substrate. Note that, for convenience of explanation, a laser beam irradiation area 3509 is used.
Although 3515 to 3512 are indicated by different patterns, these regions are irradiated with the same laser light.

Here, it is easily understood that laser light irradiation is performed a plurality of times on the laser light irradiation superimposed region indicated by 3513 to 3517. For example, laser light irradiation is performed twice or more in the region 3513 and four or more times in the region 3517. It is known that the characteristics of the polycrystalline silicon film are different when the number of times of laser light irradiation is different. Therefore, in the case of such a conventional example, the characteristics of the polycrystalline silicon film vary in the substrate plane. Therefore, in this conventional example, even if a high-output excimer laser is used, in-plane uniformity of the polycrystalline silicon film cannot be obtained. as a result,
Although the throughput is increased as compared with the case where a linear laser is used, a problem still remains regarding the in-plane uniformity of polycrystalline silicon.

In view of the above, the present invention has been made in view of the above-described problems, and is intended to improve the crystallinity of a semiconductor film when using a laser beam to polycrystallize an amorphous semiconductor film or using a laser beam. In this case, a method of producing a thin film transistor which realizes uniformity of a polycrystalline silicon film used for a thin film transistor in a substrate surface, prevents variation in characteristics of a thin film transistor using the polycrystalline silicon film as an active layer, and increases throughput. Is what you do. Another object is to provide a high-performance semiconductor device using a thin film transistor manufactured by the manufacturing method.

[0021]

[Means for Solving the Problems]

Referring to FIG. FIG. 1 shows a laser light irradiation region for polycrystallization of an amorphous semiconductor film of the present invention using a high-power excimer laser. FIG. 1 shows an active matrix type liquid crystal display device as an example of a semiconductor device using a thin film transistor manufactured by the method of the present invention. Note that although the case where silicon is used as an amorphous semiconductor film is described in this specification, an amorphous semiconductor film to be used is not limited thereto, and a film of amorphous silicon germanium or the like may be used. it can.

Reference numeral 100 denotes a substrate. 101 and 105
Is an active matrix circuit. 102 and 10
5 is a source driver circuit;
7 and 108 are gate driver circuits. In the method shown in FIG. 1, two active matrix substrates of an active matrix type liquid crystal display device can be obtained from one substrate.

Reference numerals 109 to 112 denote laser light irradiation areas, which are one shot or plural shots of laser light.
The amorphous silicon film in each region is polycrystallized. The distances (intervals) indicated by “A ₁ ” and “B ₁ ” in FIG. 1 are the distances (intervals) between the area irradiated with the laser light and the area irradiated with the laser light, respectively. Reference numeral 113 denotes a laser light non-irradiation area where laser light is not irradiated.

In the process, an active matrix circuit, a source driver circuit, and a gate driver circuit are formed after the amorphous silicon film is irradiated with a laser beam to be polycrystallized and patterned. For the sake of convenience of description, an irradiation area of laser light and an active matrix circuit, a source driver circuit,
And the gate driver circuit are shown in the same figure.

In the method for polycrystallizing an amorphous silicon film according to the present invention, as shown in FIG. 1, the regions irradiated with high-power laser light do not overlap. The distances (intervals) “A ₁ ” and “B ₁ ” between different laser light irradiation regions are determined according to the pixel pitch of the active matrix circuit, the size of the TFT, the size of the TFT of the driver circuit, and the like. The regions defined by the distances (intervals) “A ₁ ” and “B ₁ ” between the different laser light irradiation regions, that is, the regions where the laser light is not irradiated (the laser light non-irradiation region 113) are the active matrix circuit, the driver circuit, and the like. The circuit is designed so that it does not become an active layer of a thin film transistor constituting a peripheral circuit.

In FIG. 1, portions indicated by α ₁ and β ₁ are an active matrix circuit and a source driver circuit, respectively, and include portions including a boundary between a laser light irradiation area and a laser light non-irradiation area. In FIG. 10, α ₁
An enlarged view of a portion, an enlarged view of a beta ₁ part in FIG.

In FIG. 10, reference numeral 1001 denotes an active layer of a pixel TFT made of polycrystalline silicon;
Reference numeral 1003 denotes a second wiring. First wiring 10
02 functions as a gate electrode of the active layer of the thin film transistor. Note that, for convenience of description, pixel electrodes, interlayer insulating films, and the like are omitted. P _X is the pixel pitch in the X-axis (row) direction, and P _Y is the pixel pitch in the Y-axis (column) direction.
S _X is the length of the active layer in the X-axis direction, and S _Y is the _Y of the active layer.
The length in the axial direction. In FIG. 10, a triple gate TFT is used as the pixel TFT, but a single gate, a double gate, or another TFT may be used. In any case, the length of the X-axis direction of the active layer and S _X, the Y-axis direction length of the active layer and S _Y.
Note that the black portions in the drawing indicate portions where the active layer and the second wiring layer or the first wiring and the second wiring layer are in contact (connected). Further, 1004 which is a part of the first wiring 1002 is
It is formed to ensure flatness with the active layer.

According to FIG. 10, the laser light non-irradiation area 1
13 does not include the active layer of the thin film transistor.
Is understood. That is, the laser beam irradiation area 11
1 (distance between laser beam irradiation area 112) and "A"₁"
(And "B₁Laser light non-illuminated, defined by ")
There is no active layer in the emission region 113. Therefore,
Laser light non-irradiated area 113, that is, not polycrystallized
The region is not used as an active layer of the thin film transistor.
Is understood. This condition is expressed as P_X, S_X, A ₁For
P_X-S_X> A₁ Becomes

Next, reference is made to FIG. The enlarged view of the beta ₁ portion shown in FIG. 11, the source driver circuit 10
6 shows an inverter circuit. Reference numerals 1101 and 1102 denote active layers of a thin film transistor made of polycrystalline silicon, and an N-type impurity and a P-type impurity are added to their respective source and drain regions. 1103 and 1104 are first wirings, and 110
Reference numeral 3 functions as a gate electrode of the thin film transistor. 1
105 is a second wiring. Here, for convenience of explanation, an interlayer insulating film and the like are omitted. Note that the black portions in the drawing indicate portions where the active layer and the second wiring layer or the first wiring and the second wiring layer are in contact (connected).

According to FIG. 11, the laser light non-irradiation area 1
It can be understood that the active layers 1101 and 1102 do not enter the layer 13. That is, the distance (interval) between the laser light irradiation area 111 and the laser light irradiation area 112 "
Active layers 1101 and 1102 are defined in the laser beam non-irradiated area 113 defined by A ₁ "(and" B ₁ ").
Does not exist. Therefore, the laser beam non-irradiation area 113,
That is, it is understood that the regions that have not been polycrystallized are not used as the active layers 1101 and 1102 of the thin film transistor.

The crystallinity of the semiconductor film can be improved by the above-described method using laser light. Also in this case, the quality of the semiconductor film after laser light irradiation is different between the laser light irradiation area and the laser light non-irradiation area. This is because the semiconductor film is irradiated with laser light, whereby the crystallinity of the semiconductor film is improved and the quality of the semiconductor film is improved. Note that all the methods using laser light described below can be applied to the improvement of the crystallinity of the semiconductor film. This can be applied to another method of the present invention described below.

In this specification, a semiconductor film to be irradiated with a laser beam may be referred to as an “initial semiconductor film”. The “initial semiconductor film” is “amorphous or partially amorphous semiconductor film containing a crystalline component” before crystallization, and “crystalline or partially amorphous” before the crystallinity is improved. Crystalline semiconductor film containing a crystalline component ". In this specification, the term “highly crystallized semiconductor film” may be used. This “highly crystalline semiconductor film” refers to a “film with improved crystallinity, a semiconductor film with reduced intragranular defects”.

Next, reference is made to FIG. FIG. 2 shows a laser irradiation region of the amorphous silicon film of the present invention using a high-power excimer laser for polycrystallization. In addition,
FIG. 2 shows an active matrix type liquid crystal display device as an example of a semiconductor device having a thin film transistor using a polycrystalline silicon film manufactured by the method of the present invention.

Reference numeral 200 denotes a substrate. 201 is an active matrix circuit. 202 and 203 are source driver circuits, and 204 and 205 are gate driver circuits. Reference numerals 206 to 209 denote laser light irradiation regions. The amorphous silicon film in each region is polycrystallized by one or more laser light shots. The distances indicated by “A ₂ ” and “B ₂ ” in FIG. 2 are the distances between the region irradiated with the laser beam and the region irradiated with the laser beam, respectively. Reference numeral 210 denotes a laser light non-irradiation area where laser light is not irradiated. In FIG. 2, one active matrix circuit of an active matrix type liquid crystal display device is manufactured from a substrate 200.

In the process, the amorphous silicon film is irradiated with a laser beam to be polycrystallized and patterned, and then an active matrix circuit, a source driver circuit and a gate driver circuit are formed. 2
In FIG. 1, similarly to FIG. 1, the irradiation region of the laser beam, the active matrix circuit, the source driver circuit, and the gate driver circuit are shown in the same diagram for convenience of explanation.

In the method for polycrystallizing an amorphous silicon film according to the present invention, as shown in FIG. 2, the regions irradiated with high-power laser light do not overlap. The distances (intervals) “A ₁ ” and “B ₂ ” of the laser light irradiation area are determined according to the pixel pitch of the active matrix circuit, the size of the pixel TFT, the size of the TFT of the driver circuit, and the like. Distance (interval) "A ₂ " and "B" of the laser light irradiation area
_The circuit design is made so that a region indicated by ₂ ", that is, a region not irradiated with laser light (laser light non-irradiation region 113) does not become an active layer of the thin film transistor.

In FIG. 1, portions indicated by α ₂ , β ₂ and γ ₂ are an active matrix circuit, a source driver circuit and a gate driver circuit, respectively, which are boundaries between a laser light irradiation area and a laser light non-irradiation area. Refers to the part containing Figure 12 shows an enlarged view of the gamma ₂ parts. Note that the portion indicated by alpha ₂ and beta _2, is the same as the alpha ₁ and beta ₁ above, see those described.

Referring to FIG. FIG. 12 shows a buffer circuit in the gate driver circuit 204. Reference numerals 1201 and 1202 denote active layers of a thin film transistor made of polycrystalline silicon. Source layers and drain regions of the active layers 1201 and 1202 include:
Each is provided with an impurity for imparting P-type conductivity and an impurity for imparting N-type conductivity. 1203 and 1204 are first wirings, and 1205 is a second wiring. The first wiring 1203 functions as a gate electrode of the thin film transistor. Here, for convenience of explanation, an interlayer insulating film and the like are omitted. Note that, in FIG. 10, the black-out portions indicate that the active layer and the second wiring or the first and second wirings are in contact (connected) as in FIGS. 10 and 11. The part is shown.

According to FIG. 12, the laser beam non-irradiation area 2
10 includes active layers 1201 and 1 of the thin film transistor.
It is understood that 202 has not entered. That is,
Laser light irradiation area 206 and laser light irradiation area 208
The active layers 1201 and 1202 of the thin film transistor do not exist in the laser beam non-irradiation area 210 defined by the distance “B ₂ ” (and “A ₁ ”) between the active layers 1201 and 1202. Therefore, it is understood that the laser beam non-irradiated region 210, that is, the region that has not been polycrystallized, is not used as an active layer.

Here, a supplementary description will be given of the α ₂ part in FIG. In the active matrix circuit shown in FIG. 2, P _X is a pixel pitch in the X-axis (row) direction, P _Y is a pixel pitch in the Y-axis (column) direction, S _X is the length of the active layer in the X-axis direction, S _{X Y} is the length of the active layer in the Y-axis direction. in this case,
Conditions satisfying the method of the present invention, P _X, S _X, expressed using A _1, a _{P X -S X> A 2 P} Y -S Y> B 2.

Therefore, in the method for polycrystallizing an amorphous silicon film according to the present invention, the active layers of the thin film transistors constituting the active matrix circuit, source driver circuit, gate driver circuit and other peripheral circuits are provided with laser light. Non-irradiated areas are not used. Therefore, only a semiconductor film having uniform characteristics is used for the active layer of the thin film transistor.

Next, reference is made to FIG. FIG. 3 shows one of the systems for polycrystallizing the amorphous silicon film of the present invention shown in FIG. In FIG. 3, the same reference numerals as those in FIG. 1 refer to the description of FIG. 1.

In FIG. 3, reference numeral 301 denotes an amorphous silicon film formed on a substrate. Reference numeral 302 denotes a high-output laser beam, and the laser main body and the optical system are omitted for convenience of description of the drawing. Note that a high-output excimer laser is suitable for the laser body. Reference numeral 303 denotes a polycrystalline silicon film, which shows that the amorphous silicon film in a region irradiated with the laser light is polycrystalline. Reference numeral 304 denotes a stage on which the substrate 100 is set. The stage 304 is a stage X position control device 3
05 and the stage Y position control device 306. The error of the stop position of the stage 304 is 0.04
It is about μm. By moving the stage 304, the irradiation area of the laser beam 302 is controlled with high accuracy.

Further, since the laser light 302 and the substrate 100 only need to move relatively, the irradiation position of the laser light may be made variable to control the X position and the Y position of the laser light. Further, the position of both the laser beam and the substrate (that is, the stage) may be variable.

In the case shown in FIG.
Is moved three times, and the entire surface of the amorphous silicon film 301 formed on the substrate 100 is polycrystallized. Note that, as described in the description of FIG. 1, since the laser light is applied at a distance (interval) of “A ₁ ” and “B ₁ ”, there is an area where the laser light is not applied.

Next, reference is made to FIG. FIG. 4 shows one of the systems for polycrystallizing the amorphous silicon film of the present invention shown in FIG. The difference from the system shown in FIG. 3 is that the area of the laser light 401 introduced from the laser optical system has a spread in the traveling direction of the laser light. Even in such a case, by controlling the relative position of the stage and the laser beam with high accuracy, a polycrystalline silicon film with in-plane variation suppressed as much as possible can be obtained.

Next, reference is made to FIG. FIG. 5 shows one of the systems for polycrystallizing the amorphous silicon film of the present invention shown in FIG. The difference from the system shown in FIG. 3 is that the area of the laser light 501 introduced from the laser optical system narrows in the traveling direction of the laser light. Even in such a case, by controlling the relative position of the stage and the laser beam with high accuracy, a polycrystalline silicon film with in-plane variation suppressed as much as possible can be obtained.

Next, reference is made to FIG. FIG. 6 shows one of the systems for polycrystallizing the amorphous silicon film of the present invention shown in FIG. The difference from FIG. 1 is that the area of the laser light irradiated on the amorphous silicon film is controlled by passing the laser light 601 introduced from the laser optical system through the slit 602. Even in such a case, by controlling the relative position of the stage and the laser beam with high accuracy, a polycrystalline silicon film with in-plane variation suppressed as much as possible can be obtained.

Next, reference is made to FIG. FIG. 7 shows one of the systems for polycrystallizing the amorphous silicon film of the present invention shown in FIG. The difference from FIG. 6 is that the area of the laser light 701 introduced from the laser optical system is narrowed in the traveling direction of the laser light. By passing the laser light 701 through the slit 702, the area of the laser light applied to the amorphous silicon film can be controlled. Even in such a case, by controlling the relative position of the stage and the laser beam with high accuracy, a polycrystalline silicon film with in-plane variation suppressed as much as possible can be obtained.

In the system shown in FIG. 4, the area of the laser beam can be controlled by using the slits shown in FIGS. 6 and 7.

FIGS. 3 to 7 show a system for polycrystallizing the amorphous silicon film of the present invention shown in FIG. 1, but the amorphous silicon film of the present invention shown in FIG. Needless to say, it can be used as a system for polycrystallizing a film.

Next, reference is made to FIG. FIG. 8 shows a method for polycrystallizing an amorphous silicon film of the present invention when a larger substrate is handled. FIG. 8 shows an active matrix type liquid crystal display device as an example of a semiconductor device having a thin film transistor using a polycrystalline silicon film manufactured by the method of the present invention. 800 is a substrate. 801 is an active matrix circuit. 802 is a source driver circuit, and 803 and 804 are gate driver circuits. Reference numerals 805 to 816 denote irradiation regions of the laser light. The amorphous silicon film in each region is polycrystallized by one shot or a plurality of shots of the laser light. Also, "A ₃ ", "A ₄ " and "
Distance represented by A ₅ ", and" B ₃ "and" B ₄ "(interval) is the distance between the region where the region and the laser beam, each laser beam is irradiated is irradiated (interval). Further,
Reference numeral 817 denotes a laser light non-irradiation area where laser light is not irradiated. Even when such a relatively large substrate is handled, the distances (intervals) “A ₃ ”, “A ₄ ” and “A ₅ ”, and “B ₃ ” and “B ₄ ” are the pixels of the active matrix circuit, respectively. It is determined according to the pitch, the size of the pixel TFT, the size of the TFT of the driver circuit, and the like, and the circuit is designed so that the laser beam non-irradiated area does not become the active layer of the thin film transistor. Refer to FIGS. 10, 11 and 12 for the positional relationship between the laser light non-irradiation area and the active matrix circuit, the laser light non-irradiation area and the source driver circuit, and the laser light non-irradiation area and the gate driver circuit. .

Next, reference is made to FIG. FIG. 9 shows one of the systems for polycrystallizing an amorphous silicon film of the present invention when handling the substrate shown in FIG. In FIG. 9, reference numeral 301 denotes an amorphous silicon film formed on a substrate. Reference numeral 302 denotes a high-output laser beam, and the laser main body and the optical system are omitted for convenience of description of the drawing. In addition,
A high-power excimer laser is suitable for the laser body. Reference numeral 903 denotes a polycrystalline silicon film, which shows that the amorphous silicon film in a region irradiated with the laser light is polycrystalline. Reference numeral 904 denotes a stage on which the substrate 800 is set. Stage 904
Is moved by a stage X position controller 905 and a stage Y position controller 906. Stage 904
Is about 0.04 μm.
The laser light 9 is moved by moving the stage 904.
02 is controlled with high precision.

Further, since the laser light 902 and the substrate 800 need only be relatively moved, the irradiation position of the laser light may be made variable and the X position and the Y position of the laser light may be controlled. Further, the position of both the laser beam and the substrate (that is, the stage) may be variable.

In the case shown in FIG.
Moves 11 times, and the entire surface of the amorphous silicon film 901 formed on the substrate 800 is polycrystallized.
As described in the description of FIG. 1, the laser light is irradiated at distances (intervals) “A ₃ ”, “A ₄ ” and “A ₅ ”, and “B ₃ ” and “B ₄ ”. Therefore, there is a region 817 to which the laser light is not applied. The circuit is designed so that the laser light non-irradiation region 817 is not used for the active layer of the thin film transistor. This is as described above.

It should be noted that the laser beam 902 includes FIGS.
May be used.

Next, another method for polycrystallizing the amorphous silicon film of the present invention using a high-power excimer laser is shown in FIG.
Shown in FIG. 13 shows a laser beam irradiation region in the polycrystallization of the amorphous silicon film of the present invention. FIG. 13 shows an active matrix type liquid crystal display device as an example of a semiconductor device using a thin film transistor manufactured by the method of the present invention.

1300 is a substrate, 1301 and 1305
Are active matrix circuits, 1302 and 1306
Are source driver circuits, 1303, 1304, and 1307
And 1308 are gate driver circuits. 1309
Reference numerals 1312 denote irradiation regions of laser light, and the amorphous silicon film in each region is polycrystallized by irradiation of one or more shots of laser light. In the method shown in FIG. 13, a portion where the irradiation region to be irradiated with the laser light is overlapped with the end of the irradiation region to be irradiated with the laser light (the laser light irradiation overlap region 1313).
１３1317). "C ₁ " and "D ₁ " in FIG.
Are the lengths of the areas where the laser light irradiation area and the laser light irradiation area overlap each other.

In the process, an active matrix circuit, a source driver circuit and a gate driver circuit are formed after the amorphous silicon film is irradiated with laser light to be polycrystallized and patterned. For convenience of explanation, the irradiation area of the laser beam, the active matrix circuit, the source driver circuit, and the gate driver circuit are shown in the same figure. Although the laser light irradiation areas 1309 to 1312 are indicated by different hatching patterns, the respective areas are irradiated with the same laser light.

In the method shown in FIG. 13, there are laser light irradiation superimposed regions 1313 to 1317, and there are regions where the characteristics of the silicon film which has been irradiated with the laser light and which has been polycrystallized are different. In the method shown in FIG. 13, the regions of the polycrystallized silicon film having different film qualities, that is, laser light irradiation overlapping regions 1313 to 1317
The lengths “C ₁ ” and “D ₁ ” are determined according to the pixel pitch of the active matrix circuit, the size of the TFT of the driver circuit, and the like. That is, the circuit is designed so that the laser beam irradiation superimposed regions 1313 to 1317 do not become the active layer of the thin film transistor.

In FIG. 13, the portions indicated by δ ₁ and ε ₁ are an active matrix circuit region and a source driver region, respectively.
13 to 1317. FIG. 17 shows δ ₁
An enlarged view of a portion, an enlarged view of epsilon ₁ part in FIG. 18.

Referring to FIG. In FIG. 17, 17
01 is an active layer of a thin film transistor made of polycrystalline silicon, 1702 is a first wiring, and 1703 is a second wiring.
Wiring. The first wiring 1702 functions as a gate electrode of an active layer of the thin film transistor. Note that, for convenience of description, pixel electrodes, interlayer insulating films, and the like are omitted. P _X is the pixel pitch in the X-axis (row) direction, and P _Y is the Y-axis (column)
Pixel pitch in the direction. S _X is the length of the active layer in the X-axis direction, and S _Y is the length of the active layer in the Y-axis direction.

According to FIG. 17, it is understood that the active layer of the thin film transistor does not enter the laser beam irradiation superimposed region 1313. That is, the active layer does not exist in the laser beam irradiation overlapping region 1313 defined by the overlap length “C ₁ ” of the laser beam irradiation region 1311 and the laser beam irradiation region 1312. Therefore, it is understood that the laser beam irradiation overlapping region 1313 is not used as an active layer of the thin film transistor. Therefore, a polycrystalline silicon film having different characteristics is not used as an active layer of a thin film transistor. This condition, P _X, S _X, expressed by using a C _1, a P _X -S _X> C _1.

Next, reference is made to FIG. The enlarged view of epsilon ₁ portion shown in FIG. 18, the source driver circuit 13
The inverter circuit in 06 is shown. Reference numerals 1301 and 1302 denote active layers of a thin film transistor made of polycrystalline silicon. N-type impurities and P-type impurities are added to the respective source and drain regions. Reference numerals 1303 and 1304 denote first wirings, and 13
03 functions as a gate electrode of the thin film transistor.
1305 is a second wiring. Again, for convenience of explanation,
The interlayer insulating film and the like are omitted. Note that the black portions in the drawing indicate portions where the active layer and the second wiring layer or the first wiring and the second wiring layer are in contact (connected). According to FIG. 18, it is understood that the active layers 1801 and 1802 do not enter the laser beam irradiation overlapping region 1313. That is, the active layers 1301 and 1302 are provided in the laser light irradiation overlapping region 1313 defined by the overlap length “C ₁ ” (and “D ₁ ”) of the laser light irradiation region 1311 and the laser light irradiation region 1312. not exist. Therefore, the silicon film in the laser beam irradiation superimposed region 1313 is
It is understood that it is not used as an active layer of a thin film transistor. Therefore, a polycrystalline silicon film having different characteristics is not used as an active layer of a thin film transistor.

Next, reference is made to FIG. FIG. 14 shows a laser light irradiation region for polycrystallization of the amorphous silicon film of the present invention using a high-power excimer laser. Note that FIG. 14 shows an active matrix liquid crystal display device as an example of a semiconductor device having a thin film transistor using a polycrystalline silicon film manufactured by the method of the present invention.

Reference numeral 1400 denotes a substrate. Reference numeral 1401 denotes an active matrix circuit. 1402 and 1403 are source driver circuits, and 1404 and 1405 are gate driver circuits. Reference numerals 1406 to 1409 denote laser light irradiation regions. By irradiating one or more laser light shots, the amorphous silicon film in each region is polycrystallized. In the method shown in FIG. 14, as shown in FIG. 13, a portion where the irradiation region to be irradiated with the laser light is overlapped with the end of the irradiation region to be irradiated with the laser light (the laser light irradiation overlap region 14.
10 to 11414). The lengths indicated by “C ₂ ” and “D ₂ ” in FIG. 14 are the lengths of the regions where the region irradiated with the laser beam and the region irradiated with the laser beam overlap each other.

In the process, an amorphous silicon film is irradiated with a laser beam to be polycrystallized and patterned, and then an active matrix circuit, a source driver and a gate driver are formed. Similarly to FIG. 13, the laser light irradiation area, the active matrix circuit, the source driver circuit, and the gate driver circuit are illustrated in the same diagram for convenience of description. In addition,
Although the laser light irradiation regions 1406 to 1409 are indicated by different hatching patterns, the respective regions are irradiated with the same laser light.

In the method shown in FIG. 14, there are laser light irradiation superimposed regions 1410 to 1414, and there are regions in which the characteristics of the silicon film irradiated with the laser light and having been polycrystallized are different. In the method shown in FIG. 14, the regions of the polycrystalline silicon film having different film qualities, that is, the laser light irradiation overlapping regions 1410 to 1414
The lengths “C ₂ ” and “D ₂ ” are determined according to the pixel pitch of the active matrix circuit, the size of the pixel TFT, the size of the TFT of the driver circuit, and the like. That is, the laser light irradiation superimposed regions 1410 to 1414 are:
The circuit is designed so as not to be an active layer of the TFT.

In FIG. 14, portions indicated by δ ₂ , ε ₂ , and ζ ₂ are an active matrix circuit,
A source driver circuit and a gate driver circuit, each of which includes a laser beam irradiation superimposed region 1410. Figure 19 shows an enlarged view of zeta ₂ parts. The δ ₂ and ε ₂ portions are the same as the δ ₁ and ε ₁ portions shown in FIGS.

Referring to FIG. FIG. 19 shows a buffer circuit in the gate driver circuit 1404. Reference numerals 1901 and 1902 denote active layers of a thin film transistor made of polycrystalline silicon.
In addition, an impurity for imparting P-type conductivity and an impurity for imparting N-type conductivity are introduced into the source region and the drain region of 1902, respectively. 1903
And 1904 are first wirings, and 1905 is a second wiring. The first wiring 1903 functions as a gate electrode of the thin film transistor. Here, for convenience of explanation, an interlayer insulating film and the like are omitted. Note that the black portions in the drawing indicate portions where the active layer and the second wiring or the first wiring and the second wiring are in contact (connected). According to FIG. 19, the active layers 1901 and 19
02 is not entered. That is, the laser light irradiation area 1406 and the laser light irradiation area 140
The active layers 1901 and 1902 do not exist in the laser beam irradiation overlapped area 1410 defined by the length “D ₂ ” of overlap with No. 8. Therefore, it is understood that the silicon film in the laser light irradiation overlapping region 1410 is not used as an active layer of the thin film transistor. Therefore, a polycrystalline silicon film having different characteristics is not used as an active layer of a thin film transistor.

Here, the ε ₂ part in FIG. 14 will be supplementarily described. In the active matrix circuit shown in FIG. 14, P _X is a pixel pitch in the X-axis (row) direction, P _Y is a pixel pitch in the Y-axis (column) direction, S _X is the length of the active layer in the X-axis direction, S _{X Y} is the length of the active layer in the Y-axis direction. in this case,
Conditions satisfying the method of the present invention, P _X, S _X, expressed using A _1, a _{P X -S X> C 2 P} Y -S Y> D 2.

Next, reference is made to FIG. FIG. 15 shows one of the systems for polycrystallizing the amorphous silicon film of the present invention shown in FIG. In FIG. 15, the same reference numerals as those in FIG. 13 refer to the description of FIG. 13.

In FIG. 15, reference numeral 1501 denotes an amorphous silicon film formed on a substrate. Reference numeral 1502 denotes a high-output laser beam, and the laser main body and the optical system are omitted for convenience of description of the drawing. Note that a high-output excimer laser is suitable for the laser body. Reference numeral 1503 denotes a polycrystalline silicon film, which shows that the amorphous silicon film in a region irradiated with the laser light is polycrystalline.
Reference numeral 1504 denotes a stage on which the substrate 13 is mounted.
00 is set. Stage 1504 is Stage X
Position control device 1505 and stage Y position control device 1
506. The error of the stop position of the stage 1504 is about 0.04 μm. By moving the stage 1504, the irradiation area of the laser beam 302 is controlled with high accuracy.

Further, the laser beam 1502 and the substrate 1500
Since it is only necessary to move the laser light relatively, the irradiation position of the laser light may be made variable, and the X position and the Y position of the laser light may be controlled. Further, the position of both the laser beam and the substrate (that is, the stage) may be variable.

The system shown in FIG.
7 can also be used.

Next, reference is made to FIG. FIG. 16 shows a method for polycrystallizing an amorphous silicon film according to the present invention when a larger substrate is handled. In FIG. 16,
As an example of a semiconductor device having a thin film transistor using a polycrystalline silicon film manufactured by the method of the present invention,
An active matrix type liquid crystal display device is shown. 1
Reference numeral 600 denotes a substrate. Reference numeral 1601 denotes an active matrix circuit. Reference numeral 1602 denotes a source driver circuit.
603 and 1604 are gate driver circuits. 1
Reference numerals 605 to 1616 denote laser light irradiation regions. By irradiating one or more shots of the laser light, the amorphous silicon film in each region is polycrystallized. Also, “C ₃ ”, “C ₄ ” and “C ₅ ”, and “C ₃ ”
D ₃ "and" length indicated by D ₄ "is in the process area and the laser beam of each laser beam is irradiated as shown in a. Figure 16 the length of the overlap between the area to be irradiated,
At the end of the irradiation area irradiated with the laser light, there is a portion where the irradiation area irradiated with the laser light is overlapped (laser light irradiation overlapped area, typically 1617 to 1619). "C _3" in FIG. 19, "C _4", and "C _5" and "D _3"
And the length indicated by “D ₄ ” is the length of the region where the region irradiated with the laser beam overlaps the region irradiated with the laser beam.

In the process, an amorphous silicon film is irradiated with a laser beam to be polycrystallized and patterned, and then an active matrix circuit, a source driver and a gate driver are formed. Similarly to FIGS. 13 and 14, for convenience of description, the irradiation region of the laser beam and the active matrix circuit, the source driver circuit, and the gate driver circuit are shown in the same diagram. Note that the laser light irradiation areas 1605 to 1616
Are indicated by different hatching patterns, but the respective regions are irradiated with the same laser light.

The amorphous silicon film of the present invention shown in FIG.
Also in the method of polycrystallizing
The silicon film in the laser beam superimposed region indicated by 619 is
Active matrix circuit 1601, source driver circuit
Path 1602 and the gate driver circuit 1603
Not be used as the active layer of thin film transistors
Next, each circuit is designed. Note that "C_Three"," C_Four"
And "C_Five"And" D _Three"And" D_Four"
It may be the same or different. "C_Three"," C_Four"And
And "C_Five"And" D_Three"And" D_Four"The active mat
Changes depending on the design of the circuit or driver circuit.
Can be In other words, such a relatively large substrate
Even when dealing with "C_Three"," C_Four"And" C_Five"And" D
_Three"And" D_Four"Means each active matrix circuit
Pixel pitch, pixel TFT size, and driver
Is determined according to the size of the TFT in the path, etc.
So that the irradiated area does not become the active layer of the thin film transistor
design. Non-irradiated area and active matrix
Circuit, laser light non-irradiation area and source driver circuit
And laser light non-irradiation area and gate driver circuit
Refer to FIGS. 17, 18 and 19 for the positional relationship with
I want to be.

The system shown in FIG. 16 for polycrystallizing the amorphous silicon film of the present invention uses the same system as that shown in FIG.

Next, reference is made to FIG. In FIG. 29, in the method for polycrystallizing an amorphous silicon film of the present invention shown in FIG. 1, a laser beam is irradiated so that a laser beam irradiation region includes an end of a substrate. This method can also be applied to the method described with reference to the drawings other than FIG.

Incidentally, among the silicon films polycrystallized by the method shown in FIGS. 13 and 14, the silicon film in the laser beam irradiation overlapping region is usually used as the active layer of the thin film transistor as described above. There is no.
However, if the laser beam irradiation area is shifted,
Even if the silicon film in the laser beam irradiation superimposed region is used as the active layer of the thin film transistor, there is some variation, but there is no problem in the operation as the thin film transistor, and the yield of the product is not extremely reduced. Absent.

Further, all of the above-mentioned methods for polycrystallizing an amorphous silicon film employ a thermal SPC or an SP using a catalytic element.
It goes without saying that it can be used after C for further improving the crystallinity. That is, higher crystallization can be performed by irradiating the “initial semiconductor film” with a high-output excimer laser beam by the above method.

The structure of the present invention will be described below with reference to the claims.

According to the first aspect, the first step of forming a semiconductor film on a substrate and the step of forming a part of the semiconductor film to have a total energy of 5 J or more and a pulse width of 100 nsec.
A second step of irradiating the above laser light with one shot or a plurality of shots to form a highly crystallized semiconductor film, and changing a relative position between the semiconductor film and the laser light to a part different from a part of the semiconductor film There is provided a method for manufacturing a thin film transistor, comprising: a third step of repeating the second step; and a fourth step of forming a thin film transistor using the highly crystallized semiconductor film as an active layer.

According to the second aspect, the first step of forming the initial semiconductor film on the substrate, and the step of forming a part of the initial semiconductor film with a total energy of 5 J or more and a pulse width of 10
A second step of irradiating a laser beam of 0 nsec or more with one shot or a plurality of shots to form a highly crystallized semiconductor film, and changing a relative position between the initial semiconductor film and the laser beam to form a part of the initial semiconductor film; There is provided a method for manufacturing a thin film transistor, comprising: a third step of repeating the second step in different portions; and a fourth step of forming a thin film transistor using the highly crystallized semiconductor film as an active layer.

According to the third aspect, the first step of forming a semiconductor film on a substrate and the step of forming a part of the semiconductor film to have a total energy of 5 J or more and a pulse width of 100 nsec.
Irradiating the above laser light one shot or a plurality of shots, a second step of forming a highly crystallized semiconductor film, and changing the relative position between the semiconductor film and the laser light, and superimposing a part of the semiconductor, There is provided a method for manufacturing a thin film transistor, comprising: a third step of repeating the second step by irradiating a laser beam; and a fourth step of forming a thin film transistor using the highly crystallized semiconductor film as an active layer. You.

According to the fourth aspect, the first step of forming the initial semiconductor film on the substrate, and the step of forming a part of the initial semiconductor film to have a total energy of 5 J or more and a pulse width of 10
A second step of irradiating a laser beam of 0 nsec or more for one shot or a plurality of shots to form a highly crystallized semiconductor film, and changing a relative position between the initial semiconductor film and the laser beam to overlap a part of the initial semiconductor. A method of manufacturing a thin film transistor, comprising: a third step of repeating the second step by irradiating the laser light; and a fourth step of forming a thin film transistor having the highly crystallized semiconductor film as an active layer. Is provided

According to a fifth aspect, there is provided the method of manufacturing a thin film transistor according to the first or third aspect, wherein the semiconductor film is a silicon film or a silicon germanium film.

According to claim 6, the initial semiconductor film is
The method for manufacturing a thin film transistor according to claim 2 or 4, which is a silicon film or a silicon germanium film.

According to claim 7, the distance between the highly crystallized semiconductor films is about 10 μm or less.
The method for manufacturing a thin film transistor according to the above is provided.

According to an eighth aspect, there is provided the method of manufacturing a thin film transistor according to the first, second or fifth aspect, wherein a distance between a part of the semiconductor film and a different part is about 10 μm or less.

According to the ninth aspect, there is provided the method of manufacturing a thin film transistor according to the first, second, fifth, seventh or eighth aspect, wherein only the highly crystallized semiconductor film is used as an active layer.

According to a tenth aspect, the length of a portion of the semiconductor film is about 10 μm or less.
A method for manufacturing a thin film transistor according to 4 or 6 is provided.

According to the eleventh aspect, there is provided the method of manufacturing a thin film transistor according to any one of the first to tenth aspects, wherein the pulse width of the laser beam is 200 nsec or more.

According to the twelfth aspect, the first step of forming an amorphous semiconductor film on a substrate, and the step of forming a laser beam having a total energy of 5 J or more and a pulse width of 100 nsec or more on a part of the amorphous semiconductor film. Repeating one step or a plurality of shots, and changing the relative position between the amorphous silicon film and the laser beam, and repeating the second step on a portion different from a portion of the amorphous silicon film. A third step of forming a polycrystalline semiconductor film; and a fourth step of forming a thin film transistor using the polycrystalline semiconductor film as an active layer.

According to a thirteenth aspect, there is provided the method of manufacturing a thin film transistor according to the twelfth aspect, wherein the amorphous semiconductor film is an amorphous silicon film or an amorphous silicon germanium film.

According to a fourteenth aspect, an interval between the polycrystalline semiconductor films is about 10 μm or less.
The method for manufacturing a thin film transistor according to the above is provided.

According to a fifteenth aspect, there is provided the method of manufacturing a thin film transistor according to any one of the twelfth to fifteenth aspects, wherein a distance between a part of the amorphous silicon film and a different part is about 10 μm or less. .

According to a sixteenth aspect, there is provided the method of manufacturing a thin film transistor according to any one of the twelfth to fifteenth aspects, wherein a pulse width of the laser light is 200 nsec or more.

According to a seventeenth aspect, there is provided the method of manufacturing a thin film transistor according to any one of the twelfth to sixteenth aspects, wherein only a polycrystallized region of the amorphous semiconductor film is used as an active layer. .

According to the eighteenth aspect, the first step of forming an amorphous semiconductor film on a substrate and the step of forming a laser beam having a total energy of 5 J or more and a pulse width of 100 nsec or more on a part of the amorphous semiconductor film. A second step of irradiating the amorphous semiconductor film and the laser light with one shot or a plurality of shots, and irradiating the laser light to a region overlapping a part of the amorphous silicon film with the laser light. A third step of repeating the second step and polycrystallizing substantially the entire region of the amorphous semiconductor film, and a fourth step of forming a thin film transistor using the polycrystallized semiconductor film as an active layer And a method for manufacturing a thin film transistor having the following.

According to claim 19, there is provided the method of manufacturing a thin film transistor according to claim 18, wherein the amorphous semiconductor film is an amorphous silicon film or an amorphous silicon germanium film.

According to a twentieth aspect, there is provided the method of manufacturing a thin film transistor according to the nineteenth aspect, wherein the length of the region overlapping the part of the amorphous silicon film is about 10 μm or less.

According to a twenty-first aspect, there is provided the method for manufacturing a thin film transistor according to any one of the eighteenth to twentieth aspects, wherein a pulse width of the laser light is 200 nsec or more.

According to a twenty-second aspect, only the region of the polycrystalline amorphous silicon film excluding a part of the amorphous silicon film is used as an active layer.
A method for manufacturing a thin film transistor according to any one of the first to third aspects is provided.

According to claim 23, the laser light is:
The method for manufacturing a thin film transistor according to any one of claims 1 to 22, wherein the laser light is obtained by using an excimer laser device connected in two, three, or four stages.

Now, the present invention will be described in detail with reference to the following examples. Note that the following examples are only certain embodiments of the present invention, and the present invention is not limited to these embodiments.

[0109]

【Example】

(Example 1)

Example 1 In this example, the production of an active matrix type liquid crystal display device having a TFT produced using the method for polycrystallizing an amorphous silicon film of the present invention will be specifically described. In this embodiment, a plurality of TFTs are formed,
FIGS. 20 to 23 show examples in which the active matrix circuit, the driver circuit, and other peripheral circuits (logic circuit, memory circuit, and the like) are monolithically configured. In this embodiment, one pixel of the active matrix circuit and a CMOS circuit which is a basic circuit of another circuit (such as a driver circuit and another peripheral circuit) are formed at the same time. In this embodiment, the manufacturing process will be described for the case where the P-channel TFT and the N-channel TFT each have one gate electrode (the pixel TFT has two gate electrodes). A CMOS circuit using a TFT having a plurality of gate electrodes, such as a double gate type or a triple gate type, can be similarly manufactured.

Referring to FIG. First, a glass substrate 2001 is prepared as a substrate having an insulating surface. Instead of glass, a silicon substrate on which a thermal oxide film is formed can be used, or a quartz substrate can be used. A method may be employed in which an amorphous silicon film is once formed on a glass substrate or a plastic substrate, and is completely thermally oxidized to form an insulating film. Further, a glass substrate, a quartz substrate, a ceramic substrate, a plastic substrate, or a silicon substrate on which a silicon nitride film is formed as an insulating film may be used.

Next, a base film 2002 is formed. In this embodiment, a silicon oxide film (SiO ₂ ) was used. Next, an amorphous silicon film 2003 is formed. In this example, an amorphous silicon film 2003 was formed by LPCVD using Si ₂ H ₆ as a source gas. The amorphous silicon film 2003 has a final film thickness (thickness in consideration of film reduction after thermal oxidation) of 10 to 75 nm (preferably 15 to 45 n).
m).

In forming the amorphous silicon film 2003, it is important to thoroughly control the impurity concentration in the film. In the case of this embodiment, the amorphous silicon film 2003
Inside, C (carbon) which is an impurity that inhibits subsequent crystallization
And the concentration of N (nitrogen) are 5 × 10 ¹⁸ atoms
less than s / cm ³ (typically 5 × 10 ¹⁷ atoms / c
m ³ or less, preferably 2 × 10 ¹⁷ atoms / cm ³ or less, and O (oxygen) is 1.5 × 10 ¹⁹ atoms / cm ^3.
Less than (typically 1 × 10 ¹⁸ atoms / cm ³ or less,
Preferably, it is controlled to be 5 × 10 ¹⁷ atoms / cm ³ or less. This is because, if each impurity is present at a higher concentration, it will have an adverse effect on the subsequent crystallization and cause a deterioration in the film quality after the crystallization. In the present specification, the above-mentioned impurity element concentration in the film is determined by SIMS
(Mass secondary ion analysis) is defined as the minimum value in the measurement results.

In order to obtain the above configuration, L used in this embodiment is
The PCVD furnace performs dry cleaning periodically to form a film.
It is desirable to clean the room. Dry cree
10 minutes in a furnace heated to about 200 to 400 ° C.
0-300 sccm ClF _ThreeFlowing (chlorine fluoride) gas
And the fluorine generated by thermal decomposition
You only have to do the leaning. Note that, based on the knowledge of the applicant,
If the furnace temperature is 300 ° C, ClF_ThreeGas flow rate 300
In the case of sccm, a deposit of about 2 μm thickness (mainly silicon)
Can be completely removed in 4 hours
You.

Further, the hydrogen concentration in the amorphous silicon film 2003 is also a very important parameter, and a film with good crystallinity can be obtained by keeping the hydrogen content low. Therefore, it is preferable that the amorphous silicon film 2003 be formed by an LPCVD method. Note that the plasma CVD method can be used by optimizing the film formation conditions.

Next, a polycrystallizing step of the amorphous silicon film 903 by irradiation of a high-power excimer laser is performed. In this step, as described in the section of the means for solving the above problem, the irradiation area of the excimer laser is controlled according to the circuit design.

Referring to FIG. In this embodiment,
A high-power excimer laser beam with one shot of 15 J and a pulse width of 100 nsec is applied to the amorphous silicon film 2003.
To polycrystallize the amorphous silicon film. The energy density was 200 mJ / cm ² .
Thus, a polycrystalline silicon film 2004 is obtained (FIG. 20C). The output of the excimer laser is 5
J and a pulse width of 100 nsec or more (preferably 200 nsec or more) are desirable. Note that the polycrystallization of the amorphous silicon film may be performed by irradiating the above-described excimer laser with a plurality of shots.

Here, annealing may be performed at about 600 ° C. for about 20 hours in an N ₂ atmosphere or an H ₂ atmosphere.

[0120] A silicon oxide film 2002 and an amorphous silicon film 2003 are continuously formed without opening to the atmosphere, and a silicon oxide film is formed without opening to the atmosphere. The silicon film may be polycrystallized. Further, the amorphous silicon film 2003 is thermally oxidized,
A silicon oxide film may be formed over the upper surface of the amorphous silicon film and then irradiated with a laser beam to polycrystallize the amorphous silicon film.

Next, reference will be made to FIG. The polycrystalline silicon film 2004 is patterned to form thin film transistor active layers 2005 to 2007. The annealing may be performed after patterning the polycrystalline silicon film.

Next, reference will be made to FIG. After forming the active layer, a gate insulating film 2008 is formed.

Next, a metal film (not shown) containing aluminum as a main component is formed, and a prototype of a later gate electrode is formed by patterning. In this embodiment, an aluminum film containing 2 wt% of scandium is used.

Next, the porous anodic oxide films 2009 to 2016 were prepared by the technique described in JP-A-7-135318.
Non-porous anodic oxide films 2017 to 2020 and gate electrodes 2021 to 2024 are formed (FIG. 21B).

After the state shown in FIG. 21B is obtained, the gate insulating film 2008 is etched using the gate electrodes 2021 to 2024 and the porous anodic oxide films 2009 to 2016 as masks. Then, the porous anodic oxide films 2009 to 2016 are removed to obtain the state shown in FIG. Note that in FIG.
Reference numeral 27 denotes the processed gate insulating film.

Referring to FIG. Next, a step of adding an impurity element imparting one conductivity is performed. As an impurity element, P (phosphorus) or As (arsenic) for N-channel type, B (boron) or Ga (gallium) for P-type
May be used. In this embodiment, the N channel type and the P
Impurity addition for forming a channel type TFT is performed in two steps.

First, impurities are added for forming an N-channel TFT. First, the first impurity addition (in this embodiment, P (phosphorus) is used) is performed at a high accelerating voltage 80.
This is performed at about keV to form an n ⁻ region. This n ⁻ region has a P ion concentration of 1 × 10 ¹⁸ atoms / cm ³ to 1
Adjust so as to be × 10 ¹⁹ atoms / cm ³ .

Further, the second impurity addition is performed at a low acceleration voltage of about 10 keV to form an n ⁺ region. At this time,
Since the acceleration voltage is low, the gate insulating film functions as a mask. The n ⁺ region is adjusted so that the sheet resistance is 500Ω or less (preferably 300Ω or less).

Through the above steps, source and drain regions 2028 and 2029, a low-concentration impurity region (LDD region) 2032, and a channel forming region 2035 of the N-channel TFT constituting the CMOS circuit are formed. Also, the source and drain regions 203 and 2031 of the N-channel TFT forming the pixel TFT,
Low concentration impurity regions (LDD regions) 2033 and 203
4. Channel formation regions 2036 and 2037 are determined (FIG. 22A).

Note that, in the state shown in FIG.
The active layer of the P-channel TFT forming the S circuit has the same configuration as the active layer of the N-channel TFT.

Next, as shown in FIG. 22B, a resist mask 2038 is provided so as to cover the N-channel type TFT.
Addition of an impurity ion imparting P-type (boron is used in this embodiment) is performed.

This step is also performed twice as in the above-described impurity doping step. However, since it is necessary to invert the N-channel type to the P-channel type, the concentration is several times as high as the P ion addition concentration. B (boron) ion is added.

Thus, the source and drain regions 2039 and 2040 of the P-channel TFT constituting the CMOS circuit and the low concentration impurity region (LDD region) 204
1. A channel formation region 2042 is formed.
(B)).

In this embodiment, the gate electrode is formed using an aluminum film containing 2 wt% of scandium, but the gate electrode may be formed using a polycrystalline silicon film. In this case, the LDD region is formed using a sidewall such as SiO ₂ or SiN.

Next, impurity ions are activated by a combination of furnace annealing, laser annealing, lamp annealing, and the like. At the same time, the damage of the active layer in the addition step is also repaired.

Referring to FIG. Next, a stacked film of a silicon oxide film and a silicon nitride film is formed as the first interlayer insulating film 2043, and a contact hole is formed.
The source electrode and the drain electrodes 2044 to 2048 are formed to obtain a state shown in FIG. Note that an organic resin film can be used as the first interlayer insulating film 2043.

When the state shown in FIG. 22C is obtained, the second interlayer insulating film 2049 made of an organic resin film is
It is formed to a thickness of 3 μm (FIG. 23A). As the organic resin film, polyimide, acrylic, polyimide amide or the like is used. The advantages of the organic resin film are that the film formation method is simple, the film thickness can be easily increased, the parasitic capacitance can be reduced because the relative dielectric constant is low, and the flatness is excellent. . Note that an organic resin film other than those described above can be used.

Next, a part of the second interlayer insulating film 2049 is removed, and the black matrix 2 made of a light-shielding film is removed.
050 is formed. In this embodiment, titanium is used for the black matrix 2050, and an auxiliary capacitance is formed between the drain electrode 2048 of the pixel TFT and the black matrix 2050. Black matrix 2050
For example, a resin film containing a black pigment can be used.

Next, a third interlayer insulating film 2051 made of an organic resin film is formed to a thickness of 0.5 to 3 μm. As the organic resin film, polyimide, acrylic, polyimide amide or the like is used. Note that an organic resin film other than those described above can be used.

The second interlayer insulating film 2049 and the third
A contact hole is formed in the interlayer insulating film 2051, and a transparent pixel electrode 2052 is formed to a thickness of 120 nm. Since this embodiment is an example of a transmission type active matrix liquid crystal display device, a transparent conductive film such as ITO is used as a conductive film forming the transparent pixel electrode 2046.

Next, the entire substrate is heated in a hydrogen atmosphere at 350 ° C. for 1 to 2 hours, and hydrogenation of the entire device is performed, whereby dangling bonds (unpaired bonds) in the film (especially in the active layer) are formed.
To compensate. Through the above steps, a CMOS circuit and a pixel matrix circuit can be manufactured over the same substrate.

Next, a process of manufacturing an active matrix type liquid crystal display device based on the active matrix substrate manufactured by the above process will be described.

An alignment film 2053 is formed on the active matrix substrate in the state shown in FIG. In this embodiment, polyimide is used for the alignment film 2053. Next, a counter substrate is prepared. The opposite substrate includes a glass substrate 2054, an opposite electrode 2055, and an alignment film 2056.

In this example, a polyimide film was used as the alignment film. After the formation of the alignment film, a rubbing treatment was performed. In this embodiment, polyimide having a relatively small pre-tilt angle is used.

Next, the active matrix substrate and the counter substrate having undergone the above-described steps are subjected to a known cell assembling step to perform
It is bonded via a sealing material or a spacer (both not shown). Thereafter, a liquid crystal 2057 is injected between the two substrates, and completely sealed with a sealant (not shown). In this embodiment, a nematic liquid crystal is used as the liquid crystal 2057.

Thus, a transmission type active matrix liquid crystal display device as shown in FIG. 23C is completed.

Here, reference is made to FIG. In FIG.
An active matrix type liquid crystal display device manufactured according to this embodiment is shown. FIG. 24A is a perspective view of an active matrix liquid crystal display device. 2401 is an active matrix substrate, 2042 is a counter substrate, 2403 is an active matrix circuit, 24
04 is a source driver circuit, 2405 and 2406 are gate driver circuits, and 2407 is an FPC (Flexib).
le Print Circuit).

FIG. 24B is a view of the active matrix type liquid crystal display device viewed from the direction A in FIG. 24A. FIG. 24C shows an active matrix liquid crystal display device.
(A) shows a diagram viewed from the direction B.
As described above, the active matrix type liquid crystal display device according to the present embodiment has the FPCFlexible Print Ci.
(rcuit) 2407, except for the portion to which it is connected.

(Example 2)

In this embodiment, in the first embodiment, the thickness of the gate insulating film of the TFT forming the driver circuit and other peripheral circuits is the same as that of the pixel T forming the active matrix circuit.
An active matrix type liquid crystal display device when the thickness is smaller than the thickness of the gate insulating film of the FT will be described.

Referring to FIG. FIG. 25 shows an active matrix substrate of the active matrix type liquid crystal display device of this embodiment. Reference numeral 2501 denotes a T which forms a CMOS circuit which forms a driver circuit and other peripheral circuits.
FT is a gate insulating film. Reference numeral 2502 denotes a gate insulating film of the pixel TFT forming the active matrix circuit.

In this embodiment, the gate insulating film 2501 is
2 to 50 nm (typically 30 nm), and the gate insulating film 2502 has a thickness of 100 to 150 nm (typically 12 nm).
0 nm). By doing so, the CMOS circuits forming the driver circuit and other peripheral circuits can be operated at low voltage and high frequency.

Embodiment 1 can be referred to for the method of manufacturing the active matrix type liquid crystal display device of this embodiment. However, this embodiment is different from the first embodiment in that after forming the gate insulating film, the gate insulating film of the TFT constituting the CMOS circuit constituting the driver circuit and other peripheral circuits is etched and thinned. Further, after the gate insulating film is formed, a gate insulating film is further formed only on the pixel TFT, so that the CMO is improved.
It is also possible to provide a difference in thickness between the gate insulating film of the TFT forming the S circuit and the gate insulating film of the TFT forming the active matrix circuit.

(Embodiment 3)

In this embodiment, the case where the amorphous silicon film polycrystallization system of the present invention is used for manufacturing an inverted stagger type TFT will be described.

Referring to FIG. FIG. 26 is a cross-sectional view of the inverted staggered TFT of this embodiment. 260
Reference numeral 1 denotes a substrate, which is the same as that described in the first embodiment. Reference numeral 2602 denotes a silicon oxide film. Reference numeral 2603 denotes a gate electrode. Reference numeral 2604 denotes a gate insulating film. 2
Reference numerals 605, 2606, 2607 and 2608 are active layers made of a polycrystalline silicon film. In manufacturing the active layer, the same method as in the polycrystallization of the amorphous silicon film described in Example 1 was used. Note that 2605 is a source region, 2606 is a drain region, 2607 is a low concentration impurity region (LDD region), and 2608 is a channel formation region. Reference numeral 2609 denotes a channel protective film, and 2610
Is an interlayer insulating film. 2611 and 262 are a source electrode and a drain electrode, respectively.

(Example 4)

In the present embodiment, a case where the method of polycrystallizing an amorphous silicon film of the present invention is used for manufacturing an inverted staggered TFT having a different structure from that of the fourth embodiment will be described.

Referring to FIG. FIG. 27 is a cross-sectional view of the inverted staggered TFT of this embodiment. 2701
Denotes a substrate, and the substrate described in the first embodiment is used. Reference numeral 2702 denotes a silicon oxide film. Reference numeral 2703 denotes a gate electrode. 2704 is benzodiclobutene (BC
B) A film whose upper surface is planarized. Reference numeral 2705 denotes a silicon nitride film. A gate insulating film is constituted by the BCB film and the silicon nitride film. 2706, 2707, 2708
And 2709 are active layers made of a polycrystalline silicon film. In manufacturing the active layer, the same method as in the polycrystallization of the amorphous silicon film described in Example 1 was used. 2706 is a source region, 2707 is a rain region, 2708 is a low concentration impurity region (LDD region), 2
709 is a channel formation region. 2710 is a channel protective film, and 2711 is an interlayer insulating film. 2712
And 2713 are a source electrode and a drain electrode, respectively.

According to this embodiment, since the gate insulating film composed of the BCB film and the silicon nitride film is flattened, the amorphous silicon film formed thereon is also flat. Therefore, when the amorphous silicon film is polycrystallized, a more uniform polycrystalline silicon film can be obtained than a conventional inverted staggered TFT.

(Example 5)

In this embodiment, a method for manufacturing a TFT having a structure different from that of Embodiment 1 will be described with reference to FIGS. The steps up to the formation of the gate insulating film shown in FIG. 21B of the first embodiment are the same as those of the first embodiment.
Here, it is omitted. Also in this embodiment, in place of the amorphous silicon _{film, Si X Ge 1-X (} 0 <X <1) may be a silicon germanium film represented by.

Referring to FIG. Gate insulating film 3002
A 20 nm thick tantalum film (Ta film) 3003 on top
An aluminum film (Al film) 3004 containing 40 wt% scandium containing 2 wt% scandium was laminated and formed by a sputtering apparatus. Then, a current was made to flow by bringing the probe P of the anodizing apparatus into contact with the Al film 3004 to form a thin barrier type alumina film (not shown) on the surface of the Al film 3004. This anodic oxidation step is for improving the adhesion of the resist mask 3005. The conditions were as follows: an ethylene glycol solution containing 3% tartaric acid was used as the electrolytic solution, the electrolytic solution temperature was 30 ° C., the ultimate voltage was 10 V, the voltage application time was 15 minutes, and the supply current was 10 mA / 1 substrate. And the resist mask 3
03 is formed (FIG. 30B).

An alumina film (not shown) is etched with a chromium mixed acid and then an aluminum film is etched with an aluminum mixed acid to form an aluminum layer (Al layer) as a second wiring layer.
3006 was formed. The Al layer 3006 forms the upper layer of the gate wiring. Al layer 300 on the left side
Reference numeral 6 finally overlaps the active layer 3001 and functions as a gate electrode of the TFT. Also, the Al layer 3 on the right side
Reference numeral 006 is a contact portion for connecting to an external terminal later.

Next, with the resist mask 3005 left, the probe P was applied to the tantalum film 3 in an anodizing apparatus.
003 and anodized. The conditions were as follows: a 3% oxalic acid aqueous solution (temperature: 10 ° C.) was used as the electrolytic solution, the ultimate voltage was 8 V, the voltage application time was 40 minutes, and the supply current was 20 mA / 1 substrate. Under these anodic oxidation conditions, a porous anodic oxide film 234 (hereinafter referred to as porous
AO film 3007) is formed. AO film 3007
Is a porous alumina film (FIG. 30 (D)).

After removing the resist mask 3005, a voltage was again applied to the Ta film 3003 in the anodic oxidation apparatus to perform anodic oxidation. The conditions are as follows: an ethylene glycol solution containing 3% tartaric acid is used as the electrolytic solution; the electrolytic solution temperature is 10 ° C .;
The supply current was 30 mA / 1 substrate.

[0167] Tartaric acid permeates the porous AO film 3007, and the surface of the Al layer 3006 is anodized to form a barrier type anodic oxide film (referred to as a barrier AO film) 3009. The barrier AO film 1409 is a non-porous alumina film. Further, in the Ta film 3003, the exposed portion and the portion where the porous AO film 3007 is present are also anodized to form a tantalum oxide film (hereinafter TaOx).
(Referred to as membrane) 3008. The remaining tantalum layer (Ta layer) 3010 defines the first wiring layer. Note that the TaOx film 3008 is thicker than the Ta film 3003, but is shown with the same thickness in FIG. 30 for simplification (FIG. 30E).

Next, using the AO films 3007 and 3009 as a mask, the TaOx film 1408 and the gate insulating film 300 are formed.
2 is etched. The etching is performed by a dry etching method using CHF ₃ gas (FIG. 30F).

Next, the porous AO film 3007 is removed by etching with an aluminum mixed acid. Through this step, a gate wiring in which the Ta layer 3010 and the Al layer 3006 are stacked is completed (FIG. 31A).

In addition, the entire side surface of the gate wiring is covered with a TaO _x film 3008 and a barrier AO film 3009. The TaO _x film 3008 is a barrier AO film 3009
It extends outside the side.

Next, impurity ions imparting one conductivity type are added to the active layer 3001. To manufacture an N-channel TFT, phosphorus or arsenic is added, and to manufacture a P-channel TFT, boron or gallium is added. These impurity ions may be added by any of ion implantation, plasma doping, and laser doping. In the case where a CMOS circuit is formed, impurity ions may be separated using a resist mask.

This step is performed by dividing the acceleration voltage into two parts.
The first time, the acceleration voltage was set as high as about 80 keV,
For the first time, the acceleration voltage is set as low as about 30 keV. In this way, first time the TaO _X film 3008 the insulating film 3
002, impurity ions are added below,
O _X film 3008 and the insulating film 3002 serves as a mask,
No impurity ions are added therebelow.

By such an impurity ion adding step,
TFT channel formation region, source region 3012, drain region 3013, low concentration impurity region (LDD region) 3
014 and 3015 are formed in a self-aligned manner. The region 3011 is a region to which impurities are not added, and is formed with a channel formation region and an offset region. The concentration of the impurity ions added to each impurity region may be appropriately set by a practitioner (FIG. 31B).

After the step of adding the impurity ions is completed, furnace annealing, lamp annealing, laser annealing, or a combination thereof is used to perform a heat treatment to activate the added impurity ions. Note that when the tantalum layer remains on the tantalum oxide 3008 film protruding from the side surface of the alumina film 3009, the low-concentration impurity region 3014
This is inconvenient because a voltage is applied to the gate lines 3015 and 3015 by the gate wiring. Therefore, after the addition step,
It is preferable that the remaining tantalum layer is oxidized by thermal oxidation at a temperature of about 400 to 600 ° C.

Next, the interlayer insulating film 3 made of a silicon oxide film
016 is formed to a thickness of 1 μm. Next, the interlayer insulating film 3016 is patterned to form a contact hole. The formation of these contact holes 3017 to 3019 is performed as follows.

First, LAL500 manufactured by Hashimoto Kasei Co., Ltd.
The interlayer insulating film 3016 is etched using an etchant referred to as an etchant. LAL500 is an etchant obtained by adding several percent of a surfactant to buffered hydrofluoric acid obtained by mixing ammonium fluoride, hydrofluoric acid, and water. Of course,
Other buffered hydrofluoric acid may be used.

It is preferable that the buffered hydrofluoric acid used here can etch a silicon oxide film at a relatively high speed. Since the interlayer insulating film 3016 is as thick as 1 μm, a higher etching rate leads to an improvement in throughput.

When the interlayer insulating film 3016 is thus etched, the source region 3012 and the drain region 3018 are exposed in the TFT portion, and the contact hole 301 is formed.
7 and 3018 are completed. At the gate contact portion, the barrier AO film 3009 is exposed. Next, etching is advanced using thin buffered hydrofluoric acid in which ammonium fluoride, hydrofluoric acid, and water are mixed at a ratio of 2: 3: 150 (vol%).

With this buffered hydrofluoric acid, a silicon film,
That is, the source region 3012 and the drain region 3018 are hardly etched. However, the barrier AO film 3009 in the gate contact portion is etched and the underlying AO film 3009 is etched.
The l layer 3006 is also etched. Finally, when the etching reaches the Ta layer 3010, the etching stops, and a contact hole 3019 is formed (FIG. 3).
1 (C)).

When the state shown in FIG. 31C is obtained, the source wiring 1420 and the drain wiring 3 made of a conductive film are obtained.
No. 021 is formed, and an extraction wiring 3022 electrically connected to the gate wiring is formed using the same material.
(D)).

Thus, the TFT is completed. When manufacturing an active matrix liquid crystal display device, the steps in Embodiment 1 can be referred to.

(Embodiment 6)

In the present embodiment, in the crystallization of the amorphous silicon film of the first embodiment, a high-power excimer laser (type SAELC15 manufactured by Sopra) is connected in two to four stages to form a higher-power excimer laser. A laser was formed, and the amorphous silicon film was irradiated to perform polycrystallization.

(Embodiment 7)

This embodiment describes a method for polycrystallizing an amorphous silicon film in the case where the intensity distribution of laser light is slightly different at the end of the irradiation area of the high-power excimer laser. Note that the method of this embodiment can be used for forming an initial semiconductor film.

Referring to FIG. FIG. 32A shows an intensity distribution graph of the laser beam intensity. FIG.
In the graph of (A), the vertical axis represents the laser beam intensity, and the horizontal axis represents the X axis and the Y axis of the laser beam irradiation area. In a laser beam as shown in FIG.
A region indicated by L1 in which the intensity of the laser beam changes (herein referred to as a wing portion), a region in which the laser beam intensity is constant, and a region indicated by R1 in which the laser beam intensity is strong (here, the ripple portion) Call) are mixed. FIG. 32B shows the irradiation region of the laser light as viewed from above. Reference numeral 3201 denotes an area irradiated with laser light having a constant intensity, 3202 denotes an area irradiated with laser light in the ripple part, and 3203 denotes an area irradiated with laser light in the wing part.

When a laser beam having such a laser beam intensity distribution and having large L1 and R1 is used,
Care must be taken when designing the circuit. That is, the amorphous silicon film in the area of the wing where the laser light is irradiated,
It may not be completely polycrystallized, and the amorphous silicon film in the region of the ripple portion irradiated with the laser light may be microcrystallized because the laser light intensity is too high. Here, a microcrystal refers to a polycrystal having a small crystal grain size. Therefore, for example, L1 is 100
When μm and R1 are 10 μm, the film quality of the polycrystalline silicon film irradiated with the laser light in the wing portion and the ripple portion is the film quality of the polycrystallized silicon film irradiated with the laser light having a certain intensity. Will be different. Therefore, uniform film quality cannot be obtained. Therefore, it is desirable that the silicon film polycrystallized by the irradiation of the wing portion and the ripple portion with the laser beam is not used for the active layer of the thin film transistor. However, the size of the wing portion and the ripple portion can be changed by adjusting the optical system of the laser.

(Embodiment 8)

In this embodiment, the case where the laser light described in the eighth embodiment has different ripple portions and wing portions from each other will be described.

Referring to FIG. FIG. 33A shows an intensity distribution graph of the laser beam intensity. FIG.
In the graph of (A), the vertical axis represents the laser beam intensity, and the horizontal axis represents the X axis and the Y axis of the laser beam irradiation area. In a laser as shown in FIG.
A wing portion indicated by 1, a region where the laser beam intensity is constant, and a ripple portion indicated by R2 are mixed. As shown in FIG. 33A, the laser light of this embodiment is
There is only one wing and one ripple on each of the X and Y axes. FIG. 32B shows the irradiation region of the laser light as viewed from above. Reference numeral 3301 denotes a region where the laser beam intensity is constant, 3302 denotes a region where the ripple portion of the laser beam is irradiated, and 3303 denotes a region where the wing portion is irradiated with the laser beam. In this embodiment, L1
= About 50 μm and R2 = 30 μm.

When a laser beam having such an intensity distribution is used for polycrystallization of an amorphous silicon film, a silicon film microcrystallized by the laser beam in the ripple portion appears. It has been found that polycrystallization can be achieved by irradiating the microcrystalline silicon film again with the laser light in the wing portion.

Referring to FIG. FIG. 34 shows a method for polycrystallizing an amorphous silicon film according to the present embodiment. 3400 is a substrate, 3401 is an active matrix circuit, 3402 and 3403 are source driver circuits, and 3404 to 3407 are gate driver circuits. Reference numerals 3408 to 3411 denote laser light irradiation areas, which are areas to be irradiated with the laser light shown in FIG. The regions of the laser beam irradiation region where the laser light of the wing portion is irradiated and the regions of the ripple portion where the laser light is irradiated are denoted by the same reference numerals shown in FIG. In addition, the area | region where the laser beam irradiation area | region of a ripple part and the laser beam irradiation area | region of a wing part overlap is both attached | subjected.

As shown in FIG. 34, in the method of this embodiment, the position of the laser beam moves three times, and the entire substrate is polycrystallized. The silicon film microcrystallized by the irradiation of the laser beam in the ripple portion is irradiated with the laser beam in the wing portion of the moved laser beam to be polycrystallized.

Accordingly, the silicon film microcrystallized by the laser light irradiation of the ripple portion is irradiated with the laser light of the wing portion of the moved laser light, and the polycrystallized semiconductor film is replaced with the active layer of the thin film transistor. Can also be used. The size of the wing and the ripple can be changed by adjusting the optical system of the laser.

(Embodiment 9)

A semiconductor display device (typically, an active matrix type liquid crystal display device) using a thin film transistor manufactured according to the present invention has various uses. Example 1 In this example, a semiconductor device incorporating a semiconductor display device using a thin film transistor manufactured according to the present invention will be described.

Examples of such a semiconductor device include a video camera, a still camera, a projector, a head-mounted display, a car navigation, a personal computer, and a portable information terminal (mobile computer, mobile phone, etc.). One example of them is shown in FIG.

FIG. 28A shows a portable telephone,
01, an audio output unit 2802, an audio input unit 2803, a semiconductor display device 2804, operation switches 2805, and an antenna 2806.

FIG. 28B shows a video camera, which includes a main body 2807, a semiconductor display device 2808, and an audio input unit 280.
9, an operation switch 2810, a battery 2811, and an image receiving unit 2812.

FIG. 28C shows a mobile computer, which includes a main body 2813, a camera section 2814, and an image receiving section 281.
5, an operation switch 2816, and a semiconductor display device 2817.

FIG. 28D shows a head-mounted display, which comprises a main body 2818, a semiconductor display device 2819, and a band portion 2820.

FIG. 28E shows a head-mounted display, which includes a semiconductor display device 2821 and a band portion 2822.
It consists of. The head mounted display illustrated in FIG. 28E is provided with only one semiconductor display device.

FIG. 28F shows a rear type projector, 2823 is a main body, 2824 is a light source, 2825 is a semiconductor display device, 2826 is a polarizing beam splitter, 282
8 is a reflector and 2829 is a screen. In addition, it is preferable that the angle of the screen of the rear type projector can be changed while the main body is fixed, depending on the viewing position of the viewer. Note that the semiconductor display device 2823
Are used (corresponding to R, G, and B lights, respectively), thereby realizing a rear-type projector with higher resolution and higher definition.

FIG. 28G shows a front type projector, which includes a main body 2830, a light source 2831, and a semiconductor display device 2.
832, an optical system 2833, and a screen 2834. Note that three semiconductor display devices 2832 (R, G,
B corresponding to each of the B lights)
Further, a high-resolution and high-definition front type projector can be realized.

[0205]

【The invention's effect】

In the method for polycrystallizing an amorphous semiconductor film according to the present invention, a region irradiated with high-power laser light is controlled with high precision. A region not irradiated with laser light or a region irradiated with laser light in a superimposed manner is designed so as not to be an active layer of a thin film transistor.
Thus, a thin film transistor using a polycrystalline semiconductor film having uniform characteristics as an active layer can be manufactured.

Further, the method of the present invention can be used for crystallization and improvement of crystallinity of an initial semiconductor film, and a thin film transistor using a polycrystalline conductor film having uniform film quality as an active layer can be manufactured. .

[Brief description of the drawings]

FIG. 1 is a view showing a laser irradiation region of a polycrystalline amorphous silicon film of the present invention by a laser beam.

FIG. 2 is a view showing a laser irradiation region in polycrystallization of an amorphous silicon film of the present invention by a laser beam.

FIG. 3 is a diagram showing one embodiment of a system for polycrystallizing an amorphous silicon film of the present invention.

FIG. 4 is a diagram showing one embodiment of a system for polycrystallizing an amorphous silicon film of the present invention.

FIG. 5 is a diagram showing one embodiment of a system for polycrystallizing an amorphous silicon film of the present invention.

FIG. 6 is a diagram illustrating one embodiment of a system for polycrystallizing an amorphous silicon film according to the present invention.

FIG. 7 is a diagram showing one embodiment of a system for polycrystallizing an amorphous silicon film of the present invention.

FIG. 8 is a diagram showing a laser irradiation region of polycrystallizing the amorphous silicon film of the present invention by a laser beam.

FIG. 9 is a diagram illustrating one embodiment of a system for polycrystallizing an amorphous silicon film according to the present invention.

FIG. 10 is an enlarged view of a boundary between a laser light irradiation area and a laser light non-irradiation area in the amorphous silicon film polycrystallization system of the present invention.

FIG. 11 is an enlarged view of a boundary between a laser light irradiation area and a laser light non-irradiation area in the polycrystalline system for an amorphous silicon film according to the present invention.

FIG. 12 is an enlarged view of a boundary between a laser light irradiation area and a laser light non-irradiation area in the amorphous silicon film polycrystallization system of the present invention.

FIG. 13 is a view showing a laser irradiation region of polycrystallizing the amorphous silicon film of the present invention by a laser beam.

FIG. 14 is a diagram showing a laser irradiation region in polycrystallization of an amorphous silicon film of the present invention by a laser beam.

FIG. 15 is a diagram illustrating one embodiment of a system for polycrystallizing an amorphous silicon film of the present invention.

FIG. 16 is a view showing a laser irradiation region in polycrystallization of the amorphous silicon film of the present invention by a laser beam.

FIG. 17 is an enlarged view of a laser light irradiation overlapping region in the amorphous silicon film polycrystallization system of the present invention.

FIG. 18 is an enlarged view of a laser light irradiation superimposed region in the amorphous silicon film polycrystallization system of the present invention.

FIG. 19 is an enlarged view of a laser beam irradiation overlapping region in the amorphous silicon film polycrystallization system of the present invention.

FIG. 20 is a manufacturing process diagram of an active matrix liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 21 is a manufacturing process diagram of an active matrix liquid crystal display device using the polycrystalline system for an amorphous silicon film of the present invention.

FIG. 22 is a manufacturing process diagram of an active matrix type liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 23 is a manufacturing process diagram of an active matrix liquid crystal display device using the polycrystalline system of an amorphous silicon film of the present invention.

24A and 24B are a perspective view and a side view of an active matrix liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 25 is another embodiment of an active matrix type liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 26 is another embodiment of an active matrix liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 27 is another embodiment of an active matrix type liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 28 illustrates an example of a semiconductor device having a thin film transistor manufactured using the amorphous silicon film polycrystallization system of the present invention.

FIG. 29 is a diagram showing a laser irradiation region in polycrystallization of the amorphous silicon film of the present invention by a laser beam.

FIG. 30 is another manufacturing process diagram of an active matrix liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 31 is another manufacturing step diagram of an active matrix liquid crystal display device using the amorphous silicon film polycrystallization system of the present invention.

FIG. 32 is a diagram showing a laser irradiation region and laser light intensity in polycrystallization of an amorphous silicon film of the present invention by laser light.

FIG. 33 is a diagram showing a laser irradiation region and laser light intensity in polycrystallization of an amorphous silicon film of the present invention by laser light.

FIG. 34 is a diagram showing a laser irradiation region in polycrystallization of the amorphous silicon film of the present invention by a laser beam.

FIG. 35 is a diagram showing a laser irradiation region of a conventional amorphous silicon film polycrystallized by a laser beam using a large output.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 substrate 101, 105 active matrix circuit 102, 106 source driver 103, 104, 107, 108 gate driver 109, 110, 111, 112 laser light irradiation area 113 laser light non-irradiation area

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 5F052 AA02 AA11 BA01 BA02 BB07 CA02 CA07 DA02 DA10 DB02 EA12 EA15 EA16 JA02 JA04

Claims (23)

[Claims] A first step of forming a semiconductor film on a substrate; and irradiating a portion of the semiconductor film with one or more shots of a laser beam having a total energy of 5 J or more and a pulse width of 100 nsec or more. A second step of forming a crystallized semiconductor film; a third step of changing a relative position between the semiconductor film and the laser beam and repeating the second step on a portion different from a portion of the semiconductor film; A fourth step of forming a thin film transistor using a highly crystallized semiconductor film as an active layer. 2. A first step of forming an initial semiconductor film on a substrate, wherein a total energy of 5
A second step of irradiating one or more shots with a laser beam having a pulse width of J or more and a pulse width of 100 nsec or more to form a highly crystallized semiconductor film, and changing a relative position between the initial semiconductor film and the laser light;
A method for manufacturing a thin film transistor, comprising: a third step of repeating the second step on a part different from a part of the initial semiconductor film; and a fourth step of forming a thin film transistor using the highly crystallized semiconductor film as an active layer. . 3. A first step of forming a semiconductor film on a substrate, and irradiating a part of the semiconductor film with one or more shots of laser light having a total energy of 5 J or more and a pulse width of 100 nsec or more. A second step of forming a crystallized semiconductor film, and repeating the second step by changing a relative position between the semiconductor film and the laser light and irradiating the laser light so as to overlap a part of the semiconductor. A method for manufacturing a thin film transistor, comprising: a third step; and a fourth step of forming a thin film transistor using the highly crystallized semiconductor film as an active layer. 4. A first step of forming an initial semiconductor film on a substrate, wherein a total energy of 5
A second step of irradiating one or more shots of a laser beam having a pulse width of J or more and a pulse width of 100 nsec or more to form a highly crystallized semiconductor film, and changing a relative position between the initial semiconductor film and the laser light; A third step of repeating the second step by irradiating the laser light so as to overlap a part of the initial semiconductor;
And a fourth step of forming a thin film transistor using the highly crystallized semiconductor film as an active layer. 5. The method according to claim 1, wherein the semiconductor film is a silicon film or a silicon germanium film. 6. The method according to claim 2, wherein the initial semiconductor film is a silicon film or a silicon germanium film. 7. An interval between said highly crystallized semiconductor films is about 10 μm.
The method for manufacturing a thin film transistor according to claim 1, wherein m is not more than m. 8. The method for manufacturing a thin film transistor according to claim 1, wherein an interval between a part of the semiconductor film and a different part is about 10 μm or less. 9. The method according to claim 1, wherein only the highly crystallized semiconductor film is used as an active layer. 10. The method according to claim 2, wherein a part of the semiconductor film has a length of about 10 μm or less. 11. The pulse width of the laser beam is 200 n
11. The method for manufacturing a thin film transistor according to claim 1, wherein the time is at least sec. 12. A first method for forming an amorphous semiconductor film on a substrate.
A second step of irradiating a part of the amorphous semiconductor film with one or more shots of laser light having a total energy of 5 J or more and a pulse width of 100 nsec or more; A third step of changing the relative position with respect to the laser beam and repeating the second step on a portion different from a portion of the amorphous silicon film to form a polycrystalline semiconductor film.
And a fourth step of forming a thin film transistor using the polycrystalline semiconductor film as an active layer. 13. The semiconductor device according to claim 1, wherein said amorphous semiconductor film is an amorphous silicon film or an amorphous silicon germanium film.
3. The method for manufacturing a thin film transistor according to item 2. 14. An interval between said polycrystalline semiconductor films is about 10 μm.
14. The method for manufacturing a thin film transistor according to claim 12, wherein m is not more than m. 15. The method of manufacturing a thin film transistor according to claim 12, wherein an interval between a part of the amorphous silicon film and a different part is about 10 μm or less. 16. The pulse width of the laser beam is 200 n
16. The time is not less than sec.
The method for manufacturing a thin film transistor according to any one of the above. 17. The semiconductor device according to claim 12, wherein only a polycrystallized region of said amorphous semiconductor film is used as an active layer.
The method for manufacturing a thin film transistor according to any one of the above. 18. A first method for forming an amorphous semiconductor film on a substrate.
A second step of irradiating a portion of the amorphous semiconductor film with one or more shots of laser light having a total energy of 5 J or more and a pulse width of 100 nsec or more; The relative position with respect to the laser light is changed, and the laser light is applied to a region overlapping with a part of the amorphous silicon film, and the second step is repeated, so that substantially the entire region of the amorphous semiconductor film is polycrystalline. And a fourth step of forming a thin film transistor using the polycrystallized semiconductor film as an active layer. 19. The semiconductor device according to claim 1, wherein said amorphous semiconductor film is an amorphous silicon film or an amorphous silicon germanium film.
9. The method for manufacturing a thin film transistor according to item 8. 20. The method of manufacturing a thin film transistor according to claim 19, wherein a length of the region overlapping a part of the amorphous silicon film is about 10 μm or less. 21. A pulse width of the laser beam is 200 n.
21 .sec or more.
The method for manufacturing a thin film transistor according to any one of the above. 22. The thin film transistor according to claim 18, wherein only a region of said polycrystalline amorphous silicon film excluding a part of said amorphous silicon film is used as an active layer. Method. 23. The laser light according to claim 1, wherein the laser light is obtained by connecting two, three or four excimer laser devices.
23. The method for manufacturing a thin film transistor according to any one of Items 22 to 22.