JP3480208B2 - Method for manufacturing thin film semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a thin film semiconductor device in which thin film transistors having a semiconductor thin film as an active layer are integrally formed, and more specifically, to a method for forming a semiconductor thin film on an insulating substrate. , A method of manufacturing a thin film semiconductor device in which laser beam irradiation is performed for the purpose of recrystallization thereof.

[0002]

2. Description of the Related Art In recent years, a laser annealing technique using a laser beam has been developed and partially implemented as one of the methods for manufacturing a thin film semiconductor device at a low temperature.
In this laser annealing technique, a non-single crystalline semiconductor thin film such as amorphous silicon or polycrystalline silicon formed on an insulating substrate is irradiated with a laser beam to locally heat and melt the thin film, and then cooled. This is a technique for recrystallizing the semiconductor thin film.

This laser annealing technique will be specifically described. In this technique, as shown in FIG. 9, a pulse of a laser beam 2 formed in a strip shape along the vertical direction (Y direction) of an insulating substrate 1 is insulated. Semiconductor thin film 3 formed on the surface of substrate 1
Intermittently irradiate. At this time, the laser beam 2 is moved in the lateral direction (X direction) relative to the insulating substrate 1 so that the irradiation regions partially overlap with each other between the irradiations. For example, as shown in FIG. 9, the insulating substrate 1 is step-moved in the −X direction with respect to the fixed irradiation region of the laser beam 2 and the laser beam 2 is overlapped to recrystallize the semiconductor thin film 3. It is done almost uniformly.

In order to manufacture a thin film semiconductor device using such a laser annealing technique, the obtained recrystallized semiconductor thin film is used as an active layer for forming a channel region of a thin film transistor, and thin film transistors are integrated. The method of forming is adopted. That is, since the crystallized semiconductor thin film has high carrier mobility, the thin film transistor can have high performance.

By the way, since the thin film semiconductor device is suitable for, for example, a drive circuit of an active matrix type display device, its development has been actively pursued in recent years. In addition, although thin film semiconductor devices are being applied to display devices such as liquid crystal display devices, in that case,
There is a strong demand for increasing the size and cost of a transparent insulating substrate made of glass or the like. For example, in the insulating substrate 1 shown in FIG. 9, the dimension in the X direction is 400 to 500 mm,
Moreover, it is necessary to set the dimension in the Y direction to 300 to 400 mm.

In order to satisfy such an increase in size and a reduction in cost, the laser annealing technique described above is effective. That is, since the semiconductor thin film can be crystallized at a relatively low temperature by laser beam irradiation, a relatively low cost transparent substrate such as low melting point glass can be adopted. And with the adoption of such laser annealing technology,
It has become possible to manufacture a display device (thin-film semiconductor device) in which a peripheral circuit part is integrally incorporated in addition to the display part by a low-temperature process of 400 ° C. or lower using a bottom-gate thin film transistor. In addition, as described above, by overlappingly irradiating a laser beam, a semiconductor thin film having a relatively large area can be efficiently changed from amorphous to polycrystalline. Here, an excimer laser is generally used as a light source of a belt-shaped laser beam used in the laser annealing technique.

However, this excimer laser cannot extremely increase the cross-sectional area of the laser beam due to the output power. For this reason, the laser beam is shaped into a band, and as described above, the laser beam is scanned (scanning) while overlapping it so that the entire surface of the transparent insulating substrate made of a large glass or the like is irradiated.

However, in the laser beam, a portion where light stagnation occurs due to the energy distribution on the end side thereof is formed. Defects such as crystal boundaries and non-uniform crystal grain size occur. Figure 10
The width direction of the laser beam 2 shown in FIG. 9 (X in FIG.
It is a figure which shows the energy distribution in a direction [transverse direction]) typically. As shown in this figure, the laser beam 2 has a substantially uniform main beam portion 4 at a position where the energy distribution is high,
The end portion of the main beam portion 4, that is, the end portion 4 of the main beam portion 4.
The sub-beam portion 5 is formed on the outer side of a and is inclined so that the energy distribution becomes smaller toward the outer side. Here, the sub-beam portion 5 is an end portion of the laser beam in the present invention, and is necessarily generated by the action of the optical system that shapes the laser beam into a band shape. Although efforts have been made to reduce the width of the sub-beam portion 5 (the end portion of the laser beam), it has not been eliminated at present. And this sub beam 5
However, due to the non-uniform energy distribution, it becomes a portion where light stagnates as described above, and when this is irradiated, a crystal defect occurs in this irradiated portion in the semiconductor thin film. At present, for example, the width of the main beam portion 4 is about 300 to 400 μm, and the width of the sub beam portion 5 is about several μm to 10 μm.

[0009]

When manufacturing a thin film semiconductor device, the semiconductor thin film recrystallized by the laser annealing technique as described above is used as an active layer for forming a channel region of the thin film transistor. In the case of integrated formation, conventionally, no consideration has been given to the irradiation position of the sub beam portion 5,
Therefore, a channel of the thin film transistor may be formed at the irradiation position of the sub beam portion 5. Then, in the obtained thin film transistor, as shown in FIG. 11, crystal defects 7 due to the irradiation of the sub-beam portion 5 will occur in the channel region 6.

Here, in FIG. 11, reference numeral 10 is a bottom gate type thin film transistor, and this thin film transistor 10 has a gate electrode 12 formed on a glass substrate 11 and a semiconductor thin film via a gate insulating film 13 thereon. Three
With. The channel region 6 is formed immediately above the gate electrode 12 in the semiconductor thin film 3, and n ⁻ diffusion regions, that is, LDD (Lightly Doped Drain) regions 14 are formed on both sides of the channel region 6. . Further, n ⁺ diffusion regions 15 and 15 are formed outside the LDD regions 14 and 14, respectively, and the source electrode S is connected to one of the n ⁺ diffusion regions 15 and 15 and the drain electrode D is connected to the other. ing.

In the thin film transistor 10 having such a structure, the transistor characteristics are deteriorated because the crystal defect 7 caused by the irradiation of the sub-beam portion 5 is generated in the channel region 6 as described above. To do. In particular, the decrease in the current drivability becomes remarkable. Therefore, when this is used as a thin film transistor for a drive circuit in a liquid crystal display device integrated with a drive circuit, the current drivability between the thin film transistor with the crystal defect 7 and the thin film transistor without the crystal defect 7 is increased. The variation becomes large, which greatly affects the high-speed response.

FIG. 12 shows the gate voltage V of the thin film transistor.
It is a graph showing GS / drain current IDS characteristics, and a curve shown by a solid line is a transistor characteristic when the crystal defect 7 does not exist in the channel region 6, and a curve shown by a dotted line shows a case where the crystal defect 7 exists in the channel region 6. Shows the transistor characteristics of. As is clear from this graph, the presence of the crystal defect 7 in the channel region 6 reduces the current driving capability of the thin film transistor 10, and as described above, the high speed response is affected when the thin film transistor 10 is used in a drive circuit. As a result, high-speed operability is reduced. Further, as the area of the liquid crystal display device is increased, more current driving capability is required to complement the internal parasitic capacitance, but the crystal defect 7
Since the current driving capability is reduced due to the presence of, the characteristic for complementing the parasitic capacitance is also reduced.

It is possible to improve the crystalline state of the semiconductor thin film by increasing the overlap amount of the laser beam 2 formed in a band shape. However, even if the overlap amount is increased, the sub-beam portion 5 still remains. Crystal defects may remain in the irradiated area, which is not a drastic solution. Japanese Patent Laid-Open No. 3-273621 discloses a technique of irradiating only the element region with a laser beam and not irradiating the other region with a laser beam. In this technique, overlapping irradiation ( Since multiple irradiation cannot be performed, it is difficult to significantly improve the crystal quality of the semiconductor thin film existing in the device region.

In the above example, the inconvenience when the crystal defect 7 occurs in the channel region 6 has been described.
Even when the crystal defect 7 occurs in the LDD region 13, the same inconvenience occurs. The present invention has been made in view of the above circumstances. An object of the present invention is to cause a crystal defect due to irradiation of a sub-beam portion caused by an energy distribution of a laser beam, and a channel region or an LDD region is formed there. An object of the present invention is to provide a method for manufacturing a thin film semiconductor device, which prevents the inconvenience caused thereby.

[0015]

According to the method of manufacturing a thin film semiconductor device of the present invention, a film forming step of forming a semiconductor thin film on a surface of an insulating substrate spreading in a vertical direction and a horizontal direction; A laser annealing step of melting the thin film, further cooling the thin film, and recrystallizing the semiconductor thin film, and a processing step of integrally forming a thin film transistor using the recrystallized semiconductor thin film as an active layer for forming a channel region are provided. The laser annealing step intermittently irradiates a semiconductor thin film on the surface of the insulating substrate with a pulse of a laser beam formed in a strip shape along the longitudinal direction of the insulating substrate, and partially irradiates the irradiated region with the insulating substrate. Is a processing step of moving in a horizontal direction at a constant movement pitch, and the processing step forms a channel region of the thin film transistor and an LDD region. And the LDD region in the case that,
The processing step of forming the laser beam while avoiding the portion irradiated by the end portion of the laser beam is the means for solving the above problems.

According to this method of manufacturing a thin film semiconductor device,
When a thin film transistor is integratedly formed by using the recrystallized semiconductor thin film as an active layer for forming a channel region,
Since the channel region of the thin film transistor and the LDD region when forming the LDD region are formed while avoiding the portion irradiated by the end portion of the laser beam in the laser annealing process, the sub-beam portion generated by the energy distribution of the laser beam is formed. A channel region or an LDD region is not formed in a portion where a crystal defect is generated by irradiation.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A method of manufacturing a thin film semiconductor device of the present invention will be described in detail below based on an embodiment thereof.
First, as shown in FIG. 1A, a gate electrode 21 and a gate insulating film (not shown) are formed on a rectangular transparent insulating substrate 20 made of glass or the like, and the transparent insulating substrate is covered thereover. A polysilicon film is formed on the entire surface of 20, and a semiconductor thin film 22 is formed.

Next, the semiconductor thin film 22 is irradiated with a band-shaped laser beam in the same manner as in the conventional case, the semiconductor thin film is melted and further cooled to recrystallize the semiconductor thin film. Irradiation of the laser beam is similar to the conventional case shown in FIG.
Intermittent irradiation is performed along the width direction, that is, along the X direction in FIG. 9, and the irradiation region is partially overlapped in the width direction (lateral direction) at a constant movement pitch with respect to the transparent insulating substrate 20. Moving. At this time, the irradiation width of the laser beam is 300 μm, which is the width of the main beam portion 4 as shown in FIG. 10, and the overlap amount is shown in FIG.
The moving pitch A shown in (b) is set to about 15 μm, and therefore the overlap rate is set to about 95%. Here, reference numeral 23 in FIG. 1B indicates the irradiation position of the sub-beam portion 5 in the energy distribution of the laser beam shown in FIG. 10, that is, the irradiation position of the end portion of the laser beam in the present invention. The irradiation time of the laser beam is 2
It is set to 0 to 200 msec. Therefore, in the semiconductor thin film 22 melted by the laser beam irradiation, the heat received by the irradiation due to the movement of the irradiation position is transmitted to the transparent insulating substrate 2.
It diffuses to 0 and the like, and is naturally cooled by this and solidifies (recrystallizes) quickly.

Next, this recrystallized semiconductor thin film 22
As an active layer for forming a channel region, a bottom gate type thin film transistor 24 is formed as shown in FIG. When forming the thin film transistor 24,
In particular, the width B of the thin film transistor 24 is made smaller than the movement pitch A, and the thin film transistor 24 is irradiated by the end portion of the laser beam, that is, reference numeral 2
It is formed between the portions indicated by 23 and 23 while avoiding the position indicated by 3. When the thin film transistor 24 is formed in this manner, the channel region 25 and the LDD region 26 are inevitably formed while avoiding the portion irradiated by the end portion of the laser beam. Therefore, in the obtained thin film transistor 24, as shown in FIG.
5, the crystal defect 7 does not exist in the LDD region 26.

Here, the thin film transistor 24 is formed in the same manner as in the prior art, specifically, it is formed on the transparent insulating substrate 20 via the gate electrode 21 and the gate insulating film 27, and the laser annealing is performed as described above. The semiconductor thin film 22 recrystallized by the technique is patterned into the shape shown in FIG. 2 by the known lithography technique and etching technique.

Subsequently, the semiconductor thin film 22 is covered to form SiO ₂
A film is formed and further patterned by a known photoresist technique using the gate electrode 21, a lithography technique, and an etching technique to form an interlayer insulating film 28 corresponding to the channel region. Next, using the interlayer insulating film 28 as a mask, ions of n-type impurities are ion-implanted into the semiconductor thin film 22, and n ^{− −} is applied to a portion not covered with the interlayer insulating film 28.
Form a diffusion region. Further, a resist mask is formed again by the photoresist technique, the lithography technique, and the etching technique, and n-type impurities are ion-implanted into the portion not covered with the resist mask to form the n ⁺ diffusion region 29.

Then, the resist mask is removed and the n ^- diffusion region covered with the resist mask is replaced by the LDD region 2
In addition to the above, the channel region 25 is defined as a region covered with the interlayer insulating film 28 and not subjected to ion implantation. After that, an interlayer insulating film 30 is formed so as to cover the interlayer insulating film 28, the LDD region 26, and the n ⁺ diffusion region 29, a contact hole (not shown) is further formed therein, and a conductive material is embedded in the contact hole. The source electrode S and the drain electrode D are formed.

Next, an example in which such a method for manufacturing a thin film semiconductor device is applied to manufacturing a liquid crystal display device will be described. FIG. 3 is a schematic configuration diagram showing an example of a liquid crystal display device obtained by applying the manufacturing method of the present invention. An active matrix type liquid crystal display device using the thin film semiconductor device obtained by the present invention as a drive substrate. Is. This liquid crystal display device has a built-in peripheral circuit, and in addition to the liquid crystal display unit 40, peripheral circuits such as a vertical shift register 41 and a horizontal shift register 42 are integrally formed.

In the liquid crystal display section 40, a gate line 43 and a signal line 44 are formed so as to intersect with each other. A thin film transistor 24 for driving pixel switching is formed at the intersection of these lines 43 and 44. The source electrode (not shown) of the thin film transistor 24 is connected to the corresponding signal line 44, the drain electrode (not shown) is connected to one end of the liquid crystal capacitor 45 and the additional capacitor 46, and the gate electrode is connected to the corresponding gate line. There is. The other ends of the liquid crystal capacitor 45 and the additional capacitor 46 are connected to the counter electrode 47. The thin film transistor 2
4 are integrated and formed with a constant array pitch, and this array pitch is equal to the interval between the signal lines 44.

The vertical shift register 41 operates in response to a start signal supplied from the outside, and sequentially outputs selection pulses to each gate line 43 via the buffer circuit 48. With such a configuration, the liquid crystal capacitors 45 are selected for each row. Also, to each signal line 44, image signals RED and GREE of three colors are externally supplied via an analog switch 49.
N and BLUE are supplied. The horizontal register 42 operates according to a start signal supplied from the outside, and sequentially opens and closes each analog switch 49 via the sample hold circuit 50.
With such a configuration, the image signals are sequentially output to the signal line 44.
Are sampled and written in the selected liquid crystal capacitor 45 in a dot-sequential manner.

The vertical shift register 4 described above is used.
1, horizontal shift register 42, buffer circuit 48,
The sample and hold circuit 50 is also composed of the thin film transistor 24 obtained by the present invention and having no crystal defects in the channel region and the LDD region. Figure 4 (a)
4 is a diagram showing a latch circuit used in the vertical shift register 41 and the horizontal shift register 42, and FIG.
The clocked CMOS inverter denoted by reference numeral 51 in (a) has a configuration as shown in FIG. 4 (b), and the CMOS inverter denoted by reference numeral 52 has a configuration as shown in FIG. 4 (c). The thin film transistor 24 according to the present invention is used as the NchTr in FIGS. 4B and 4C. Similarly, the analog switch 49 in FIG. 3 has the circuit configuration shown in FIG. 4D, and the NchT in FIG.
The thin film transistor 24 according to the present invention is also used as r.

Here, as shown in FIG. 4A, the CMO
A capacitor 53 for generating an output voltage is connected to the output part of the S inverter 52.
Has a function of holding the output of the latch portion of the shift register. When the capacitance 53 increases, on the contrary, the high-speed response that causes a change in voltage deteriorates,
More current drive capability is needed. On the other hand, the shift register 41 (42) shown in FIG. 3 is designed on the assumption that uniform thin film transistors are formed. It will not be done.

Therefore, in the liquid crystal display device shown in FIG. 3, as described above, crystal defects are formed in the channel region 25 and the LDD region 26 obtained in the present invention in the vertical shift register 41, the horizontal shift register 42 and the like. Since the thin film transistor 24 which does not have such a structure is used, even if the capacitance 53 shown in FIG. 4A is increased, it has a sufficient current driving ability to follow the increase.

FIG. 5 is a diagram showing another example of the active matrix type liquid crystal display device shown in FIG. 3. The difference from the liquid crystal display device shown in FIG. 3 is that the liquid crystal display device of FIG. In contrast to scanning, the liquid crystal display device shown in FIG. 5 employs line-sequential scanning.
That is, in the liquid crystal display device shown in FIG. 5, the line memory circuit 54 is used instead of the sample hold circuit 50. The line memory circuit 54 has three color image signals R
ED, GREEN and BLUE are supplied, and these image signals are stored in the line memory circuit 54 at high speed line by line. Then, the analog switches 49 connected to the respective signal lines 44 are simultaneously controlled to be opened / closed by a line-sequential signal supplied from the outside, and the image signals for one line stored in the line memory circuit 54 are simultaneously line-sequentially. Liquid crystal capacity of selected row 45
It is designed to be written in.

Even in such a liquid crystal display device, the vertical shift register 41 and the horizontal shift register 42 are provided.
And the like, and the channel region 25 and LDD obtained by the present invention.
Since the thin film transistor 24 having no crystal defect is used in the region 26, even if the capacitance 53 shown in FIG. 4A increases, the thin film transistor 24 has sufficient current drivability to follow it. .

FIG. 6 is a diagram showing a specific configuration example of the liquid crystal display section 40 of the active matrix type liquid crystal display device shown in FIG. As shown in FIG. 6, the liquid crystal display unit 4
At 0, the liquid crystal 61 is filled between the drive substrate (transparent insulating substrate) 20 and the counter substrate 60 which are arranged at a predetermined interval. A counter electrode 62 is formed on the entire inner surface of the counter substrate 60, and a bottom gate type thin film transistor 63 having no crystal defects according to the present invention is formed on the drive substrate 20. The thin film transistor 63 has a gate electrode 64 made of Mo / Ta, Mo, etc.
A gate insulating film 65 made of SiO ₂ / P-SiN or the like and a semiconductor thin film 66 made of polysilicon or the like are sequentially stacked from the bottom. An anodic oxide film 64a of TaMo _x or the like is formed on the gate electrode 64 so as to cover the surface thereof.

Further, just above the gate electrode 64,
An interlayer insulating film 67 made of P—SiO ₂ or the like is formed immediately above the channel region (not shown) in the semiconductor thin film 66, and the channel region is protected by this. Thin film transistor 63 having such a configuration
Are covered with a first interlayer insulating film 68 made of PSG or the like. A source electrode S and a drain electrode D made of Mo or Al are formed on the first interlayer insulating film 68, and the source electrode S and the drain electrode D are opened in the first interlayer insulating film 68. The thin film transistor 63 is electrically connected through the contact hole (not shown). In addition, these electrodes S and D are
Similarly, it is covered with a second interlayer insulating film 69 made of PSG or the like, and a metal pattern 70 made of Ti or the like having a light shielding property is formed on the second interlayer insulating film 69. The metal pattern 70 having the light shielding function is made of Si.
It is covered with a third interlayer insulating film 71 made of O ₂ or the like, and a transparent pixel electrode 72 made of ITO or the like is patterned on the third interlayer insulating film 71. The pixel electrode 72 is electrically connected to the thin film transistor 63 via the metal pattern 70 and the drain electrode D. With such a structure, the liquid crystal 61 is formed between the pixel electrode 72 and the counter electrode 62 to form a liquid crystal capacitance.

FIG. 7 is a diagram showing a modification of the liquid crystal display section 40 of the liquid crystal display device shown in FIG. 6, and in FIG. 7, the liquid crystal 61 and the counter substrate 60 are not shown. This liquid crystal display unit also has basically the same configuration as the liquid crystal display unit shown in FIG. 6, except that the second interlayer insulating film 69 is removed, and the metal pattern 70 and the electrode S, This is the point where D is directly connected.

In the above embodiment, the thin film transistor formed according to the present invention is shown in FIG.
The bottom gate type thin film transistor 24 shown in FIG. 8 is not limited to this, and a top gate type thin film transistor as shown in FIG. 8 may be formed. Here, in the thin film transistor shown in FIG. 8, a semiconductor thin film 81 such as polysilicon is formed on a transparent insulating substrate 80, and a channel region 82, an LDD region 83, and an n ⁺ diffusion region 84 are formed in this semiconductor thin film 81. There is. Further, the semiconductor thin film 81 is covered to cover the gate insulating film 85.
And a gate electrode 86 is formed directly on the channel region 82 on the gate insulating film 85. Then, an interlayer insulating film 87 is formed so as to cover the gate electrode 86, and the source electrode S and the drain electrode D are connected to each other through the contact hole (not shown) of the interlayer insulating film 87.
⁺ Connected to the diffusion region 84. Further, even in the thin film transistor having such a configuration, since no crystal defect is formed in the channel region 82 and the LDD region 83, the thin film transistor has a sufficient current driving capability.

In the above embodiment, the thin film transistor formed according to the present invention is NchTr.
Of course, hTr may be used. In that case, since it is not necessary to form the LDD region, it is necessary to prevent the channel region from being formed at the position where the end of the laser beam is irradiated. Good. Further, in the above-described embodiment, the entire thin film transistor is formed while avoiding the portion irradiated with the end portion of the laser beam, but in the present invention, at least the channel region and the LDD region (however, L
If it is formed by avoiding (when the DD region is formed), it is possible to prevent the inconvenience caused by the crystal defect.

When the present invention is applied to the manufacture of an active matrix type liquid crystal display device, as shown in the above embodiment, a driving circuit system such as a vertical shift register or a horizontal shift register, and a thin film transistor of a liquid crystal display section. In order to eliminate crystal defects in the channel region and the like, the thin film transistor formation position, the irradiation position of the laser beam and the movement pitch thereof are determined in advance, and the crystal defects in the channel region and the LDD region of all thin film transistors are determined. It is desirable that there be no

[0037]

As described above, according to the method of manufacturing a thin film semiconductor device of the present invention, when a thin film transistor is integratedly formed by using a recrystallized semiconductor thin film as an active layer for forming a channel region, When forming an LDD region, this LDD region
In the laser annealing process, the end of the laser beam is formed so as to avoid the irradiated portion,
The channel region or the LDD region is not formed at the portion where the crystal defect is generated by the irradiation of the sub-beam portion generated by the energy distribution of the laser beam.

Therefore, since it is possible to eliminate such inconveniences caused by crystal defects and to integrally form a thin film transistor having a uniform driving capability, for example, when the present invention is applied to manufacture of a liquid crystal display device, a thin film transistor is manufactured. The vertical image deterioration of can be reduced,
Further, it is possible to suppress the occurrence of defective pixels on a straight line in the vertical direction and the horizontal direction, and it is possible to suppress display unevenness caused by the variation in the driving capability of the thin film transistors, which enables uniform image display and high quality. A liquid crystal display device can be provided. In addition, since the current driving capability can be greatly improved, the response of the thin film transistor can be significantly improved as compared with the conventional one.

[Brief description of drawings]

1A to 1C are plan views of relevant parts for explaining a method of manufacturing a thin film semiconductor device of the present invention in the order of steps.

FIG. 2 is a side sectional view of an essential part showing an example of a schematic configuration of a thin film transistor formed according to the present invention.

FIG. 3 is a schematic configuration diagram of an example of a liquid crystal display device obtained by applying the present invention.

4A and 4B are circuit diagrams of constituent elements of the liquid crystal display device shown in FIG. 3, where FIG. 4A is a diagram showing a latch circuit, and FIG. 4B is a diagram showing FIG.
Figure showing the circuit of the clocked CMOS inverter inside,
(C) is a figure which shows the circuit of the CMOS inverter in (a), (d) is a figure which shows the circuit of an analog switch.

FIG. 5 is a schematic configuration diagram of another example of a liquid crystal display device obtained by applying the present invention.

6 is a side cross-sectional view of an essential part showing an example of the configuration of a liquid crystal display section in the active matrix liquid crystal display device shown in FIG.

7 is a side sectional view of a main part showing another example of the configuration of the liquid crystal display section in the active matrix type liquid crystal display device shown in FIG.

FIG. 8 is a side sectional view of an essential part showing another example of the schematic configuration of the thin film transistor formed according to the present invention.

FIG. 9 is a schematic diagram for explaining a conventional laser beam irradiation method.

FIG. 10 is a schematic diagram showing energy distribution of a laser beam.

FIG. 11 is a side sectional view of an essential part showing an example of a conventional thin film transistor.

FIG. 12 is a graph showing electrical characteristics of a conventional thin film transistor.

[Explanation of symbols]

20, 80 Transparent insulating substrate 22, 81 Semiconductor thin film 23 Location irradiated by laser beam end 24 Thin film transistor 25, 82 Channel region 26, 83 LDD region

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/336 H01L 29/786 H01L 21/20 H01L 21/268

Claims (4)

(57) [Claims] 1. A film forming step of forming a semiconductor thin film on a surface of an insulating substrate which extends in a vertical direction and a horizontal direction, and irradiating a laser beam to melt the semiconductor thin film and further cool the semiconductor thin film to re-heat the semiconductor thin film. A method of manufacturing a thin film semiconductor device, comprising: a laser annealing step of crystallization; and a processing step of integrally forming a thin film transistor using the recrystallized semiconductor thin film as an active layer for forming a channel region, the laser annealing step Intermittently irradiates a semiconductor thin film on the surface of the insulating substrate with a pulse of a laser beam formed in a strip shape along the longitudinal direction of the insulating substrate, and the irradiation region is partially overlapped with the insulating substrate at a constant level. In the processing step, the channel region of the thin film transistor is irradiated by the end portion of the laser beam. Method of manufacturing a thin film semiconductor device, characterized in that the process step of forming avoiding. 2. The processing step is a processing step in which the thin film transistor is formed with a width narrower than the movement pitch and the thin film transistor is formed while avoiding a portion irradiated by an end portion of the laser beam. The method for manufacturing a thin film semiconductor device according to claim 1. 3. A film forming step of forming a semiconductor thin film on a surface of an insulating substrate which extends in a vertical direction and a horizontal direction, irradiating a laser beam to melt the semiconductor thin film and further cool the semiconductor thin film to re-heat the semiconductor thin film. A method of manufacturing a thin film semiconductor device, comprising: a laser annealing step of crystallization; and a processing step of integrally forming a thin film transistor using the recrystallized semiconductor thin film as an active layer for forming a channel region, the laser annealing step Intermittently irradiates a semiconductor thin film on the surface of the insulating substrate with a pulse of a laser beam formed in a strip shape along the longitudinal direction of the insulating substrate, and the irradiation region is partially overlapped with the insulating substrate at a constant level. A processing step of moving in a lateral direction at a moving pitch, wherein the processing step includes a channel region and an LDD region of the thin film transistor at an end of the laser beam. Method of manufacturing a thin film semiconductor device characterized in that but a process of forming avoiding the portion irradiated. 4. The processing step is a processing step in which the thin film transistor is formed with a width narrower than the movement pitch, and the thin film transistor is formed while avoiding a portion irradiated by an end portion of the laser beam. The method for manufacturing a thin film semiconductor device according to claim 3.