JP2002353237A - Method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operation characteristics and reliability of a semiconductor device, to reduce the number of processes and a manufacturing cost, and to increase a yield, in the semiconductor device as typified by an active matrix type liquid crystal display device using thin film transistors(TFT). SOLUTION: In order to recover crystallinity of a semiconductor film after a doping process, activate impurity elements, and reduce contact resistances after the formation of a wiring, a laser beam is irradiated from the backside of the substrate after the formation of a wiring. Since two processes of a heat treatment after a doping process and a heat treatment after the formation of a wiring can be substituted by a process for irradiating the substrate by a laser beam from the backside of the substrate, it is possible to reduce the number of processes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device having a circuit composed of thin film transistors (hereinafter, referred to as TFTs). For example, the present invention relates to an electro-optical device represented by a liquid crystal display device and a configuration of an electric device including the electro-optical device as a component. Note that in this specification, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics, and the above-described electro-optical device and electric device are also included in the category.

[0002]

2. Description of the Related Art In recent years, a technique for manufacturing a semiconductor device in which a semiconductor thin film is formed on an insulating substrate, for example, a semiconductor device using a semiconductor element such as a thin film transistor (TFT) has been rapidly developed. The reason is that the demand for liquid crystal display devices (typically, active matrix liquid crystal display devices) has increased.

In the manufacturing process of a semiconductor device, a heat treatment performed by a known method (thermal annealing, laser annealing, rapid thermal annealing (RTA), etc.) is an essential step. In particular, it is indispensable after a doping process or after a wiring is formed.

[0004] In the doping process, the energy of ions implanted into the semiconductor film is much higher than the binding energy of elements forming the semiconductor film. For this reason, ions implanted into the semiconductor film repel elements forming the semiconductor film from lattice points, causing defects in the crystal. Therefore, after the doping process, the defect is recovered, and at the same time, a heat treatment is performed to activate the implanted impurity element. Activating the impurity element can be achieved by changing the region to which the impurity element is added to a low-resistance region and using a low-concentration drain (LDD: Li
ghtly Doped Drain) is an important process to function as a region, source region and drain region.

The heat treatment performed after the formation of the wiring is a particularly important step for reducing the Schottky barrier at the contact portion between the semiconductor film and the wiring to form an ohmic contact and to reduce the contact resistance. .
When the semiconductor film and the wiring form an ohmic contact, a voltage drop and a power loss at a contact portion between the wiring and the semiconductor film during device operation can be ignored, so that a high-performance semiconductor device can be manufactured. In addition, the heat treatment in this step is almost always performed by a thermal annealing method.

[0006]

However, as the performance of the semiconductor device has been improved, the formation of a layer having a relatively low heat-resistant temperature, such as the metalization of the gate electrode, has been increasing. In particular, since the heat treatment after the above-described doping process and after the formation of the wiring is performed after the formation of the gate electrode and the wiring, it is desired to perform the processing at a low temperature in a short time.

Further, it is very important to reduce the number of steps as much as possible in order to reduce the manufacturing cost and improve the manufacturing yield.

The present invention is a technique for solving such a problem. In a semiconductor device typified by an active matrix type liquid crystal display device manufactured using a TFT, the operation characteristics and reliability of the semiconductor device are considered. It is an object of the present invention to reduce the number of steps and reduce the manufacturing cost and improve the yield.

[0009]

SUMMARY OF THE INVENTION The present invention provides a method for recovering crystallinity of a semiconductor film after doping, activating an impurity element, and reducing contact resistance after forming a wiring. The semiconductor device is characterized in that laser light is emitted from a side (in this specification, a surface opposite to a surface on which a semiconductor film is formed). Here, the reason for irradiating the laser light from the back surface side of the substrate is that the wiring blocks the laser light from the front surface side of the substrate (defined as a surface on which the semiconductor film is formed in this specification), This is because the contact portion between the semiconductor film and the semiconductor film is not heated. Further, depending on the material of the interlayer insulating film, some of the materials have low heat resistance, which is for preventing laser light from being directly irradiated to the interlayer insulating film.

In the present invention, it is essential that a contact portion between the wiring and the semiconductor film is heated. Therefore, laser light having a wavelength capable of heating the semiconductor film and reaching the contact portion between the wiring and the semiconductor film through the semiconductor film is used. As a result, the conventional heat treatment after the doping treatment and the heat treatment after the wiring formation are performed.
Two steps can be performed in one step of irradiating laser light from the back side of the substrate after forming the wiring,
The number of steps can be reduced as compared with the related art.

Of course, even if the laser light does not reach the contact portion, it is possible to recover the crystallinity of the semiconductor film and activate the impurity element by the heat of the laser light heating the semiconductor film. At the same time, the contact portion between the semiconductor film and the wiring is also heated, so that the contact resistance can be reduced.

Further, when irradiating a laser beam, the substrate is
It may be heated to about 00 degrees. This makes it possible to perform laser light irradiation with a lower energy density. Thereby, the area of the laser beam on the irradiation surface can be increased, and the throughput of the process can be improved.

According to a manufacturing method of the present invention, a first insulating film is formed on a semiconductor film formed on a surface of a substrate, and a first conductive layer is formed on the semiconductor film via the first insulating film. And selectively introducing an impurity element into the semiconductor film to form a channel formation region overlapping with the first conductive layer, and a source region and a drain region including an impurity region.
Forming a second insulating film covering the semiconductor film, the first insulating film, and the first conductive layer, the first insulating film and the second insulating film, or the second insulating film; Partially exposing a portion of the source region and the drain region to form a second conductive layer in contact with the source region or a portion of the drain region; And irradiating the semiconductor film with laser light.

Another method of the present invention is to form a semiconductor film on a surface of a substrate, crystallize the semiconductor film by heat treatment, and form a first insulating film on the crystallized semiconductor film. And a first insulating film is formed on the semiconductor film via a first insulating film.
Forming a channel forming region overlapping with the first conductive layer, and forming a source region and a drain region formed of an impurity region by selectively introducing an impurity element into the semiconductor film; Forming a second insulating film covering the film, the first insulating film, and the first conductive layer;
The first insulating film and the second insulating film or the second insulating film is partially etched to expose a part of the source region and the drain region, and the source region or the drain A second conductive layer which is in contact with part of the region is formed, and the semiconductor film is irradiated with laser light from the back surface side of the substrate.

Further, in another manufacturing method of the present invention, a semiconductor film is formed on a surface of a substrate, a metal element is introduced into the semiconductor film, and the semiconductor film is crystallized by a heat treatment. Forming a first insulating film on the film, forming a first conductive layer on the semiconductor film via the first insulating film,
An impurity element is selectively introduced into the semiconductor film to form a channel formation region overlapping with the first conductive layer, and a source region and a drain region including the impurity region. Forming a second insulating film covering the film and the first conductive layer, and partially etching the first insulating film and the second insulating film or the second insulating film; Exposing a part of the source region and the drain region, forming a second conductive layer in contact with the source region or a part of the drain region, and irradiating the semiconductor film with laser light from the back surface side of the substrate It is characterized by doing.

In each of the above manufacturing steps, the impurity element is an impurity element imparting n-type or an impurity element imparting p-type. Further, an impurity element imparting n-type and an impurity element imparting p-type may be used.

In each of the above manufacturing steps, it is preferable that a part of the laser light is transmitted through the substrate and the semiconductor film. 2 and 3 show transmittance with respect to wavelength. FIG. 2A shows a 1737 glass substrate (thickness 0.7).
FIG. 2B shows the transmittance with respect to the wavelength of the synthetic quartz glass substrate (thickness: 1.1 mm), and FIG. 3A shows the transmittance with respect to the wavelength formed on the 1737 glass substrate. FIG. 3 shows the transmittance with respect to the wavelength when laser light was irradiated from the surface side of the crystalline silicon film (thickness: 55 nm).
(B) shows the transmittance with respect to the wavelength when laser light is irradiated from the surface side of the crystalline silicon film (thickness: 55 nm) formed on the 1737 glass substrate. From FIGS. 2 and 3,
The wavelength of the laser light is 350 nm (preferably 400 n
m) or more.

Further, when irradiating a laser beam, the substrate
It may be heated to about 00 degrees. This makes it possible to perform laser light irradiation with a lower energy density. Thereby, the area of the laser beam on the irradiation surface can be increased, and the throughput of the process can be improved.

As the laser beam used in the present invention, for example,
YAG laser, YVO ₄ laser, YLF laser, YAl
An O ₃ laser, a glass laser, or the like can be used after being modulated to a second harmonic by a known method. Also, a ruby laser, a Ti: sapphire laser, or the like can be used.
In particular, a YAG laser which is superior in pulse energy is preferable.

Further, a Q switching method (Q modulation switching method) often used in a YAG laser may be used. This is from the state where the Q value of the laser resonator is sufficiently low,
This is a method of outputting a steep pulse laser having a very high energy value by rapidly increasing the Q value. This is a known technique.

It is desirable that the laser beam is formed into a linear shape by an optical system and irradiated. With a linear beam,
Unlike the case of using spot-shaped laser light that requires front-back, left-right scanning, scanning in a direction perpendicular to the long axis direction of the linear beam (or moving the laser beam irradiation position relative to the irradiation surface) ), Laser irradiation can be performed on the entire irradiation surface, and mass productivity is high. Note that shaping the laser light into a linear shape means that the laser light is shaped so that the shape of the irradiation surface when the object is irradiated with the laser light becomes linear. That is, it means that the cross-sectional shape of the laser beam is formed into a linear shape. The term “linear” as used herein does not mean “line” in a strict sense, but means a rectangle (or a long ellipse) having a large aspect ratio. For example, it refers to one having an aspect ratio of 10 or more (preferably 100 to 10,000).

In each of the above manufacturing steps, the material of the semiconductor film is not limited, but a compound semiconductor film such as silicon or a silicon germanium (SiGe) alloy may be preferably used.

In the above-mentioned manufacturing process, the metal element is Fe, Co, Ni, Ru, Rh, Pd, Os, I
One or more elements selected from r, Pt, Cu, Ag, Au, Sn, and Sb.

By applying the present invention as described above, the number of steps can be reduced and the performance of a semiconductor device can be greatly improved. For example, taking a TFT as an example, by sufficiently activating an impurity element, a region to which the impurity element is added can be made a low-resistance region to function as an LDD region, a source region, and a drain region. I do. The operation speed of the TFT is improved by reducing the contact resistance. In particular, the mobility can be improved.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.

First, a base insulating film 12 is formed on a substrate 11. As the substrate 11, a glass substrate or a synthetic quartz glass substrate having a property of transmitting laser light is used. In addition, as the base insulating film 12, an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed. Although an example in which a single-layer structure is used as the base insulating film 12 is shown here, a structure in which two or more insulating films are stacked may be used. Note that the base insulating film need not be formed.

Next, a semiconductor film is formed on the base insulating film 12. The semiconductor film has an amorphous structure by a known means (sputtering method, LPCVD method, plasma CVD method, etc.) in a range of 25 to 100 nm (preferably 30 to 60 nm).
(nm). The material of the semiconductor film is not limited, but is preferably silicon or silicon germanium (SiG
e) It is good to form with an alloy etc. Then, after performing a known crystallization process (eg, a laser crystallization method, a thermal crystallization method, or a thermal crystallization method using a catalyst such as nickel) to form a crystalline semiconductor film, patterning is performed. The layers 13 and 14 are formed. Here, the semiconductor layer 13 is an n-channel TFT, and the semiconductor layer 14 is a p-channel TFT
Shall be manufactured.

Gate insulating film 1 covering semiconductor layers 13 and 14
5 is formed. The gate insulating film 15 is formed by a plasma CVD method,
The insulating film containing silicon is formed to a thickness of 40 to 150 nm by a sputtering method or the like.

Next, as shown in FIG. 1A, a conductive film 16 having a thickness of 100 to 500 nm is formed on the gate insulating film 15. Ta, W, Ti, Mo, C
It may be formed of an element selected from u, Cr, Nd, and Al, or an alloy material or a compound material containing the above element as a main component, and is represented by a crystalline silicon film doped with an impurity element such as phosphorus. A semiconductor film may be used. Also,
AgPdCu alloy may be used. Further, an oxide conductive film (typically, an ITO film) transparent to visible light may be used.

Next, a resist mask (not shown) is formed by photolithography, and an etching process for forming electrodes and wirings is performed to form conductive layers 17 and 18.

Next, using the conductive layers 17 and 18 as a mask, the gate insulating film 15 is selectively removed to remove the insulating layer 1.
9 and 20 are formed. (FIG. 1B) Of course, the gate insulating film 15 need not be selectively removed.

Then, the first and second doping processes
Is performed to add an impurity element to the semiconductor layer. (Figure 1
(B) The doping treatment is an ion doping method or an ion doping method.
What is necessary is just to carry out by an ON injection method. The conditions of the ion doping method are
Dose of 1 × 10¹³~ 5 × 10 ¹⁵/ Cm^TwoAnd the accelerating power
The pressure is set at 5 to 100 keV. In this case, the conductive layer 1
7 and 18 are masks for impurity elements, and are self-aligned
As a result, impurity regions 21 and 22 are formed. First, the n-type
The impurity element to be added is added, and then the p-type is added.
To form impurity regions 26 and 27.
You. However, as shown in FIGS. 1B and 1C,
When an impurity element imparting n-type is added to
The semiconductor layer forming the channel type TFT is made of resist.
Covering with a mask 23 and adding an impurity element imparting p-type
Semiconductor layer for forming an n-channel TFT
Is covered with a mask 25 made of resist.

Next, an interlayer insulating film 28 is formed. This interlayer insulating film 28 is formed of an inorganic insulating material or an organic insulating material. Alternatively, the insulating film may be formed using a film whose surface is flattened. Of course, the interlayer insulating film 28 may have a laminated structure instead of a single layer.

It is preferable to perform a heat treatment at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen to hydrogenate the semiconductor layer. This step is to terminate dangling bonds of 10 ¹⁶ to 10 ¹⁸ / cm ^{3 in} the semiconductor layer by thermally excited hydrogen. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed. In any case, it is desirable that the defect density in the semiconductor layers 104 to 108 be 10 ¹⁶ / cm ³ or less. For this purpose, about 0.01 to 0.1% of hydrogen of the total number of atoms contained in the semiconductor layers is applied. Just do it. Of course, it may be performed before forming the interlayer insulating film.

Then, a wiring 29 electrically connected to each impurity region is formed. As the wiring, Ta,
It may be formed of an element selected from W, Ti, Mo, Cu, Cr, Nd, and Al, or an alloy material or a compound material containing the above element as a main component, or may be crystalline doped with an impurity element such as phosphorus. A semiconductor film typified by a silicon film may be used. Further, an AgPdCu alloy may be used.
Further, an oxide conductive film (typically, an ITO film) transparent to visible light may be used. Here, an example in which a single-layer structure is used as the wiring 29 is described, but a structure in which two or more layers are stacked may be used.

FIG. 1F is a view for explaining a step of irradiating a laser beam from the back side of the substrate to recover the crystallinity of the semiconductor layer, activate the impurity element, and reduce the contact resistance. To irradiate laser light from the back side of the substrate,
For example, the stage on which the substrate is mounted may be made of a light-transmitting glass or synthetic quartz. Also, the wavelength of the laser beam is desirably a wavelength that appropriately transmits the substrate and the semiconductor film.
m (preferably 400 nm) or more. For example, YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, or the second harmonic of the glass laser, ruby laser, Ti: can be used sapphire laser or the like. Especially, YAG which is superior in pulse energy
Lasers are preferred. Irradiation with laser light can be performed in a vacuum, in the air, in a nitrogen atmosphere, or the like. Further, the substrate may be heated to about 500 degrees when the laser light is applied. This makes it possible to perform laser light irradiation with a lower energy density. Thereby, the area of the laser beam on the irradiation surface can be increased, and the throughput of the process can be improved.

A laser beam is irradiated using any one of the above-described laser oscillators and in any one of the above-mentioned atmospheres.
The optimum irradiation conditions vary depending on the materials of the electrodes and wirings, etc., so that the practitioner may appropriately determine them.

According to the laser light irradiation method of the present invention, the recovery of the crystallinity of the semiconductor film, the activation of the impurity element, and the reduction of the contact resistance are sufficiently performed. The electrical characteristics of the TFT thus manufactured are improved,
The characteristics of a semiconductor device manufactured using T can also be improved.

The present invention having the above configuration will be described in more detail with reference to the following embodiments.

[0040]

[Embodiment 1] An embodiment of the present invention will be described with reference to FIG.

First, a base insulating film 12 is formed on a substrate 11. As the substrate 11, a glass substrate or a synthetic quartz glass substrate having a property of transmitting laser light is used. In addition, as the base insulating film 12, an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed. Although an example in which a single-layer structure is used as the base insulating film 12 is shown here, a structure in which two or more insulating films are stacked may be used. Note that the base insulating film need not be formed. In this embodiment,
150 nm film thickness on synthetic quartz glass substrate by CVD method
Is formed.

Next, a semiconductor film is formed on the base insulating film 12. The semiconductor film has an amorphous structure by a known means (sputtering method, LPCVD method, plasma CVD method, etc.) in a range of 25 to 100 nm (preferably 30 to 60 nm).
(nm). The material of the semiconductor film is not limited, but is preferably silicon or silicon germanium (SiG
e) It is good to form with an alloy etc. Then, after performing a known crystallization process (eg, a laser crystallization method, a thermal crystallization method, or a thermal crystallization method using a catalyst such as nickel) to form a crystalline semiconductor film, patterning is performed. The layers 13 and 14 are formed. Here, the semiconductor layer 13 is an n-channel TFT, and the semiconductor layer 14 is a p-channel TFT
Shall be manufactured. In this embodiment, after an amorphous silicon film having a thickness of 55 nm is formed by a CVD method, the amorphous silicon film is crystallized using a XeCl excimer laser.
Semiconductor layers 13 and 14 are formed by patterning.

Gate insulating film 1 covering semiconductor layers 13 and 14
5 is formed. The gate insulating film 15 is formed by a plasma CVD method,
The insulating film containing silicon is formed to a thickness of 40 to 150 nm by a sputtering method or the like. In this embodiment, a silicon oxide film having a thickness of 100 nm is formed by a CVD method.

Next, as shown in FIG. 1A, a conductive film 16 having a thickness of 100 to 500 nm is formed on the gate insulating film 15. Ta, W, Ti, Mo, C
It may be formed of an element selected from u, Cr, Nd, and Al, or an alloy material or a compound material containing the above element as a main component, and is represented by a crystalline silicon film doped with an impurity element such as phosphorus. A semiconductor film may be used. Also,
AgPdCu alloy may be used. Further, an oxide conductive film (typically, an ITO film) transparent to visible light may be used. In this embodiment, a film thickness of 400
nm of Ta is formed.

Next, a mask (not shown) made of a resist is formed by photolithography, and an etching process for forming electrodes and wirings is performed to form conductive layers 17 and 18.

Next, using the conductive layers 17 and 18 as a mask, the gate insulating film 15 is selectively removed to remove the insulating layer 1.
9 and 20 are formed. (FIG. 1B) Of course, the gate insulating film 15 need not be selectively removed.

Then, the first and second doping processes
Is performed to add an impurity element to the semiconductor layer. (Figure 1
(B) The doping treatment is an ion doping method or an ion doping method.
What is necessary is just to carry out by an ON injection method. The conditions of the ion doping method are
Dose of 1 × 10¹³~ 5 × 10 ¹⁵/ Cm^TwoAnd the accelerating power
The pressure is set at 5 to 100 keV. In this case, the conductive layer
17 and 18 serve as masks for impurity elements,
As a result, impurity regions 21 and 22 are formed. First, n-type
Is added, followed by p-type
To form impurity regions 26 and 27
I do. However, as shown in FIGS. 1B and 1C,
When an impurity element imparting n-type is added to
The semiconductor layer forming the channel type TFT is made of resist.
Covering with a mask 23 and adding an impurity element imparting p-type
Semiconductor layer for forming an n-channel TFT
Is covered with a mask 25 made of resist. In this embodiment,
Phosphorus is used as an impurity element to impart n-type
The accelerating voltage is 10 keV and the average concentration is 2 × 1
0²⁰/ Cm^ThreeIntroduce so that. Also gives p-type
Boron is used as the impurity element to be
keV, average density 2 × 10²⁰/ Cm^ThreeSo that
Introduce.

Next, an interlayer insulating film 28 is formed. This interlayer insulating film 28 is formed of an inorganic insulating material or an organic insulating material. Alternatively, the insulating film may be formed using a film whose surface is flattened. Of course, the interlayer insulating film 28 may have a laminated structure instead of a single layer. In this embodiment, a silicon oxide film having a thickness of 1.6 μm is formed.

It is desirable to perform a heat treatment at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen to hydrogenate the semiconductor layer. This step is to terminate dangling bonds of 10 ¹⁶ to 10 ¹⁸ / cm ^{3 in} the semiconductor layer by thermally excited hydrogen. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed. In any case, it is desirable that the defect density in the semiconductor layers 104 to 108 be 10 ¹⁶ / cm ³ or less. For this purpose, about 0.01 to 0.1% of hydrogen of the total number of atoms contained in the semiconductor layers is applied. Just do it. Of course, it may be performed before forming the interlayer insulating film.

Then, a wiring 29 electrically connected to each impurity region is formed. As the wiring, Ta,
It may be formed of an element selected from W, Ti, Mo, Cu, Cr, Nd, and Al, or an alloy material or a compound material containing the above element as a main component, or may be crystalline doped with an impurity element such as phosphorus. A semiconductor film typified by a silicon film may be used. Further, an AgPdCu alloy may be used.
Further, an oxide conductive film (typically, an ITO film) transparent to visible light may be used. Here, an example in which a single-layer structure is used as the wiring 29 is described, but a structure in which two or more layers are stacked may be used. In this embodiment, a Ti film having a thickness of 50 nm and an alloy film having a thickness of 500 nm (an alloy film of Al and Ti)
Is formed by patterning the laminated film.

FIG. 1F is a view for explaining a step of irradiating a laser beam from the back side of the substrate to recover the crystallinity of the semiconductor layer, activate the impurity element, and reduce the contact resistance. To irradiate laser light from the back side of the substrate,
For example, the stage on which the substrate is mounted may be made of a light-transmitting glass or synthetic quartz. Also, the wavelength of the laser beam is desirably a wavelength that appropriately transmits the substrate and the semiconductor film.
m (preferably 400 nm) or more. For example, YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, or the second harmonic of the glass laser, ruby laser, Ti: can be used sapphire laser or the like. Especially, YAG which is superior in pulse energy
Lasers are preferred. Irradiation with laser light can be performed in a vacuum, in the air, in a nitrogen atmosphere, or the like. Further, the substrate may be heated to about 500 degrees when the laser light is applied. This makes it possible to perform laser light irradiation with a lower energy density. Thereby, the area of the laser beam on the irradiation surface can be increased, and the throughput of the process can be improved. In this embodiment, a YAG laser is used, and the second harmonic (wavelength 532 nm) is modulated by a nonlinear optical element and irradiated in the atmosphere.

According to the present invention, the recovery of the crystallinity of the semiconductor film,
Activation of the impurity element and reduction of the contact resistance are sufficiently performed. And the TF thus produced
The electrical characteristics of T are improved, and the characteristics of a semiconductor device manufactured using the TFT can also be improved.

[Embodiment 2] In this embodiment, a method for manufacturing a TFT having a structure different from that of Embodiment 1 will be described.
However, only a method for manufacturing an n-channel TFT will be described here.

According to the first embodiment, the state shown in FIG. In this embodiment, the conductive layer is formed of W.

Subsequently, etching is performed to form a gate electrode 31 having a tapered end. A mask (not shown) made of a resist is formed by using a photolithography method, and an etching process for forming an electrode and a wiring is performed. In this embodiment, ICP is used as the etching process.
(Inductively Coupled Plasma)
Using an etching method, CF ₄ and Cl ₂ are used as etching gases.
And O ₂ , and the respective gas flow ratios are 25/25 /
10 (sccm), 500 W RF (13.56 MHz) power was applied to the coil-type electrode at a pressure of 1 Pa to generate plasma and perform etching. Here, a dry etching apparatus (Model E645- □ ICP) using ICP manufactured by Matsushita Electric Industrial Co., Ltd. was used. A 150 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. This etching process etches the W film to make the end of the conductive layer tapered. Note that in order to perform etching without leaving a residue on the gate insulating film, 10 to 20%
It is preferable to increase the etching time at a ratio of about. In the above etching treatment, the end of the conductive layer becomes tapered due to the effect of the bias voltage applied to the substrate side by making the shape of the resist mask appropriate. The angle of the tapered portion is 15 to 45 °. 32
Denotes a gate insulating film, and a region which is not covered with the conductive layer 31 is etched to a thickness of about 20 to 50 nm to form a thinned region.

Then, a doping process is performed to introduce an impurity element. In the doping treatment, an impurity element imparting n-type or an impurity element imparting p-type is introduced by an ion doping method, an ion implantation method, or the like. An impurity element imparting n-type and an impurity element imparting p-type may be introduced. In addition, hydrogen may be added. By the doping process, a region 33 where the impurity element is introduced at a high concentration, a region 34 where the impurity element is introduced at a low concentration due to the taper of the end of the gate electrode, and a region (channel forming region) 35 where the impurity element is not introduced are formed. In this embodiment, phosphorus is used as an impurity element imparting n-type. The phosphorus implantation conditions were 5% PH ₃ diluted with hydrogen, an acceleration voltage of 10 keV, and a dose of 1.5 × 10 ¹⁵ / cm ^2.
And The time required for the implantation is about 8 minutes, and phosphorus having an average concentration of 2 × 10 ²⁰ / cm ³ can be implanted into the crystalline semiconductor film.

Subsequently, after forming the interlayer insulating film 36 and the wiring 37 according to the first embodiment, laser light is irradiated from the back side of the substrate to recover the crystallinity of the semiconductor film, activate the impurity element, and Reduce the contact resistance sufficiently. The electrical characteristics of the TFT manufactured as described above are improved, and the characteristics of a semiconductor device manufactured using the TFT can also be improved.

[Embodiment 3] In this embodiment, a manufacturing process of a TFT having a structure different from that of Embodiment 1 or Embodiment 2 will be described.

First, a light-transmitting glass substrate or a synthetic quartz glass substrate is used as the substrate 40. Further, as the base insulating film, an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film may be formed in a single layer or a stacked structure. Note that the base insulating film need not be formed. In this embodiment, a synthetic quartz glass substrate is used as the substrate 40.

A conductive film is formed, and etching is performed to form a conductive film having a desired shape. Although there is no particular limitation on the material of the conductive film, Ta, W, Ti, Mo, Al, Cu, Cr,
It may be formed of an element selected from Nd, or an alloy material or a compound material containing the element as a main component. Also,
A semiconductor film typified by a crystalline silicon film doped with an impurity element such as phosphorus may be used. AgPdCu
An alloy may be used. Needless to say, the conductive film is not limited to a single layer but may be a stacked layer. In this embodiment, the film thickness is 400 nm.
Of the W film is formed. The W film is formed by a sputtering method using a W target. Other 6
It can also be formed by a thermal CVD method using tungsten fluoride (WF ₆ ). Then, the conductive layer 41 is formed by patterning.

As the insulating film 42, an insulating film containing silicon such as a silicon oxide film or a silicon nitride oxide film (SiOxNy) may be used by a known means (sputtering method, LPCVD method, plasma CVD method, or the like). Of course, the insulating film is not limited to a single layer but may be a stacked layer. In this embodiment, the plasma CV
A 150 nm-thick silicon oxide film is formed by Method D.

Subsequently, the semiconductor film 43 having an amorphous structure
Using known means (sputtering, LPCVD, plasma C
VD method, etc.) to 25 to 80 nm (preferably 30 to 80 nm)
60 nm). The material of the semiconductor film is not limited, but is preferably silicon or silicon germanium (Si
Ge) may be formed of an alloy or the like. In this embodiment, an amorphous silicon film having a thickness of 50 nm is formed by a plasma CVD method. Then, a known crystallization method (laser crystallization method, RT
A or a thermal crystallization method using a furnace annealing furnace, a thermal crystallization method using a metal element that promotes crystallization, or the like) is performed to crystallize the semiconductor film. In this embodiment, an aqueous nickel acetate solution (concentration in terms of weight: 5 ppm, volume: 5 ml) is applied to the surface of the amorphous silicon film by a spin coating method (solution coating method), and is exposed to a nitrogen atmosphere at 550 ° C. for 4 hours. The metal element for promoting crystallization is not only nickel but also F
e, Co, Ru, Rh, Pd, Os, Ir, Pt, C
There are u, Ag, Au, Sn, and Sb, and one or more metal elements selected from these can be used. In addition, the addition method of the metal element other than the spin coating method,
There is also a method of adding a metal element by a plasma treatment method, an evaporation method, an ion implantation method, or a sputtering method. Note that the heating time and temperature for crystallization depend on the semiconductor film and the added metal element, and may be determined as appropriate by an operator.

Subsequently, a mask 44 is formed, a doping process is performed, and an impurity element is selectively introduced into the semiconductor film. In the doping treatment, one or more elements selected from rare gas elements and an impurity element imparting n-type or an impurity element imparting p-type are introduced by an ion doping method or an ion implantation method. In addition, hydrogen may be added. In this embodiment, phosphorus is used as an impurity element for imparting n-type. The phosphorus is implanted under the conditions of 5% PH ₃ diluted with hydrogen, an acceleration voltage of 80 keV, and a dose of 1.5 × 10 ¹⁵ / cm ² .

When a metal element is used to crystallize a semiconductor film as in this embodiment, heat treatment is performed.
It is desirable to perform gettering of the metal element.
By the heat treatment, the metal element moves from the channel formation region to the region to which the impurity element is added, so that the channel formation region can be a high-resistance region.

Then, after removing the mask and forming a semiconductor layer to be an active region, according to the first embodiment,
An interlayer insulating film 48 and a wiring 49 are formed. Subsequently, laser light is irradiated from the back surface side of the substrate to recover the crystallinity of the semiconductor film, activate the impurity element, and reduce the contact resistance. By irradiating laser light from the back side,
Since the gate electrode 41 is heated and the semiconductor layer is further heated by the heat, the efficiency is high. The electrical characteristics of the TFT manufactured as described above are improved, and the characteristics of a semiconductor device manufactured using the TFT can also be improved.

In this embodiment, only the impurity region 47 functioning as a source region and a drain region is formed as an impurity region. However, the present invention can be applied to an LDD structure or a GOLD (gate-drain overflow) even in a bottom gate structure.
(LDD) structure.

Embodiment 4 In this embodiment, a method for manufacturing an active matrix substrate will be described with reference to FIGS. In this specification, a substrate in which a CMOS circuit, a driver circuit, a pixel portion having a pixel TFT, and a storage capacitor are formed on the same substrate is referred to as an active matrix substrate for convenience.

First, in this embodiment, Corning # 70
A substrate 400 made of glass such as barium borosilicate glass typified by 59 glass or # 1737 glass, or aluminoborosilicate glass is used. Note that a quartz substrate may be used as the substrate 400. Further, a plastic substrate having heat resistance enough to withstand the processing temperature of this embodiment may be used.

Next, a base film 401 made of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed on the substrate 400. Although a two-layer structure is used as the base film 401 in this embodiment, a single-layer film of the insulating film or a structure in which two or more layers are stacked may be used. As the first layer of the base film 401, a plasma CVD method is used, and SiH ₄ , N
The silicon oxynitride film 401a formed using H ₃ and N ₂ O as a reaction gas is formed to a thickness of 10 to 200 nm (preferably 50 to 10 nm).
0 nm). In this embodiment, a 50-nm-thick silicon oxynitride film 401a (composition ratio: Si = 32%, O = 27%,
N = 24%, H = 17%). Next, as a second layer of the base film 401, S
A silicon oxynitride film 401b formed using iH ₄ and N ₂ O as a reaction gas is formed to a thickness of 50 to 200 nm (preferably 100 to 200 nm).
(About 150 nm). In this embodiment, a 100-nm-thick silicon oxynitride film 401b (composition ratio Si =
32%, O = 59%, N = 7%, H = 2%).

Next, semiconductor layers 402 to 40 are formed on the underlying film.
6 is formed. The semiconductor layers 402 to 406 are formed to have a thickness of 25 to 100 nm (preferably 30 to 60 nm) by a known means (sputtering, LPCVD, plasma CVD, or the like).
m), and a known crystallization method (laser crystallization method, thermal crystallization method using RTA or furnace annealing furnace, thermal crystallization using a metal element that promotes crystallization) Method). Then, the obtained crystalline semiconductor film is patterned into a desired shape to form a semiconductor layer 402.
To 406 are formed. Examples of the semiconductor film include an amorphous semiconductor film, a microcrystalline semiconductor film, and a crystalline semiconductor film.
A compound semiconductor film having an amorphous structure such as an amorphous silicon germanium film may be used. In this embodiment, an amorphous silicon film having a thickness of 55 nm is formed by a plasma CVD method. Then, a crystalline silicon film is formed by a laser crystallization method, and semiconductor layers 402 to 406 are formed by a patterning process using a photolithography method.

When a crystalline semiconductor film is formed by a laser crystallization method, a pulse oscillation type or continuous emission type excimer laser, YAG laser, YVO ₄ laser, YLF
A laser, a YAlO ₃ laser, a glass laser, a ruby laser, a Ti: sapphire laser, or the like can be used.
In the case of using these lasers, a method in which a laser beam emitted from a laser oscillator is linearly condensed by an optical system and irradiated to a semiconductor film is preferably used. The crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is set to 300 Hz, and the laser energy density is set to 100 to 700 mJ / cm ² (typically 200 to 700 mJ / cm ² ).
３００300 mJ / cm ² ). When a YAG laser is used, its second harmonic is used and pulse oscillation frequencies 1 to 3 are used.
00 Hz, and a laser energy density of 300 to 10
MJ / cm ² may (typically 350~500mJ / cm ²⁾ to. And a width of 100 to 1000 μm, for example 400 μ
The laser beam condensed linearly at m may be irradiated over the entire surface of the substrate, and the superposition rate (overlap rate) of the linear beam at this time may be set to 50 to 98%.

After the formation of the semiconductor layers 402 to 406, a small amount of impurity element (boron or phosphorus) may be doped in order to control the threshold value of the TFT.

Next, a gate insulating film 407 covering the semiconductor layers 402 to 406 is formed. The gate insulating film 407 is formed by a plasma CVD method or a sputtering method and has a thickness of 40 to
The insulating film containing silicon is formed to have a thickness of 150 nm. In this embodiment, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N =
7%, H = 2%). Needless to say, the gate insulating film is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.

When a silicon oxide film is used, TEOS (Tetraethyl Orthosilicate) is formed by a plasma CVD method.
And O ₂ , a reaction pressure of 40 Pa and a substrate temperature of 300 to
400 ° C., high frequency (13.56 MHz) power density 0.
It can be formed by discharging at 5 to 0.8 W / cm ² .
The silicon oxide film thus manufactured is thereafter
Good characteristics as a gate insulating film can be obtained by thermal annealing at up to 500 ° C.

Next, a film thickness of 20 is formed on the gate insulating film 407.
A first conductive film 408 having a thickness of 100 to 100 nm;
A second conductive film 409 having a thickness of 00 nm is stacked. In this embodiment, a first conductive film 408 made of a TaN film with a thickness of 30 nm and a second conductive film 409 made of a W film with a thickness of 370 nm are stacked. The TaN film was formed by a sputtering method, and was sputtered using a Ta target in an atmosphere containing nitrogen. The W film was formed by a sputtering method using a W target. Alternatively, it can be formed by a thermal CVD method using tungsten hexafluoride (WF ₆ ). In any case, it is necessary to lower the resistance in order to use it as a gate electrode, and the resistivity of the W film is 20 μΩc.
m or less. The resistivity of the W film can be reduced by enlarging the crystal grains. However, when the W film contains many impurity elements such as oxygen, the crystallization is inhibited and the resistance is increased. Therefore, in this embodiment, the W film is formed by a sputtering method using a high-purity W (purity of 99.9999%) target, and further taking care not to mix impurities from the gas phase during film formation. By forming, the resistivity 9
２０20 μΩcm was realized.

In this embodiment, the first conductive film 408
Is TaN and the second conductive film 409 is W, but there is no particular limitation, and any of Ta, W, Ti, Mo, Al, Cu,
It may be formed of an element selected from Cr and Nd, or an alloy material or a compound material containing the element as a main component.
Alternatively, a semiconductor film typified by a polycrystalline silicon film doped with an impurity element such as phosphorus may be used. AgP
A dCu alloy may be used. A first conductive film formed of a tantalum (Ta) film, a second conductive film formed of a W film, a first conductive film formed of a titanium nitride (TiN) film, and a second conductive film formed of a titanium nitride (TiN) film; Are combined with a W film, the first conductive film is formed of a tantalum nitride (TaN) film, and the second conductive film is formed of an Al film, and the first conductive film is formed of a tantalum nitride (TaN) film. Alternatively, a combination of the second conductive film and the Cu film may be used.

Next, resist masks 410 to 415 are formed by photolithography, and a first etching process for forming electrodes and wirings is performed.
The first etching process is performed under the first and second etching conditions. (FIG. 6B) In this embodiment, the first etching condition is an ICP etching method, CF ₄ , Cl _2, and O ₂ are used as etching gases, and the respective gas flow ratios are 25/25 /. 10 (sccm) and 1 Pa
500W RF (13.56MHz) to coil type electrode at pressure of
Power was applied to generate plasma to perform etching. Here, a dry etching apparatus using ICP manufactured by Matsushita Electric Industrial Co., Ltd. (Model E645-ICP)
Was used. 150W RF on substrate side (sample stage)
(13.56 MHz) Power is applied and a substantially negative self-bias voltage is applied. The W film is etched under the first etching conditions to make the end of the first conductive layer tapered.

Thereafter, a mask 410 made of resist is formed.
The second etching condition was changed without removing 415, CF ₄ and Cl ₂ were used as etching gases, the respective gas flow ratios were 30/30 (sccm), and the pressure was 1 Pa to form a coil-type electrode. RF (13.56 MHz) power of 500 W was applied to generate plasma, and etching was performed for about 30 seconds. The substrate side (sample stage) also has a 20 W RF (13.56
MHz) power is applied and a substantially negative self-bias voltage is applied. Under the second etching condition in which CF ₄ and Cl ₂ are mixed, the W film and the TaN film are etched to the same extent. Note that in order to perform etching without leaving a residue on the gate insulating film, the etching time is preferably increased by about 10 to 20%.

In the first etching process, the shape of the mask made of resist is made appropriate so that
The ends of the first conductive layer and the second conductive layer are tapered due to the effect of the bias voltage applied to the substrate side. The angle of the tapered portion is 15 to 45 °. In this manner, the first shape conductive layers 417 to 422 (the first conductive layers 417a to 422a and the second conductive layers 417b to 417b) formed of the first conductive layer and the second conductive layer by the first etching process.
2b) is formed. 416 is a gate insulating film,
The region not covered by the conductive layers 417 to 422 having the
A region that is etched and thinned by about 50 nm is formed.

Next, a second etching process is performed without removing the resist mask. (FIG. 6C) Here, the W film is selectively etched using CF ₄ , Cl _2, and O _{2 as} an etching gas. At this time, second conductive layers 428b to 433b are formed by a second etching process. On the other hand, the first conductive layers 417a to 422a
The second shape conductive layer 428 is hardly etched.
To 433 are formed.

Then, a first doping process is performed without removing the resist mask to add a low concentration of an impurity element imparting n-type to the semiconductor layer. The doping treatment may be performed by an ion doping method or an ion implantation method. The condition of the ion doping method is that the dose is 1 × 10 ^{13 to} 5
× 10 ¹⁴ / cm ² and an acceleration voltage of 40 to 80 keV. In this embodiment, the dose is set to 1.5 × 10 ¹³ / cm ²
And the acceleration voltage is set to 60 keV. An element belonging to Group 15 of the periodic table, typically phosphorus (P) or arsenic (As) is used as the n-type impurity element. Here, phosphorus (P) is used. In this case, conductive layers 428 to 433 serve as a mask for the impurity element imparting n-type, and impurity regions 423 to 427 are formed in a self-aligned manner. 1 × 10 ¹⁸ to 1 × 10 ²⁰ / cm ³
Is added within the concentration range of n.

After removing the resist mask, a new
In addition, resist masks 434a to 434c are formed.
The second doping at a higher accelerating voltage than the first doping process.
A doping process is performed. The condition of the ion doping method is
1 × 10¹³~ 1 × 10 ¹⁵/cm^TwoAnd the accelerating voltage is 6
The operation is performed at 0 to 120 keV. Doping process is second
Of the conductive layers 428b to 432b
And a semiconductive layer below the tapered portion of the first conductive layer.
Doping is performed so that an impurity element is added to the body layer.
Subsequently, the accelerating voltage is lowered from the second doping process to
3A to obtain the state shown in FIG.
You. The condition of the ion doping method is that the dose amount is 1 × 10¹⁵~ 1
× 10¹⁷/cm^TwoAnd the acceleration voltage is 50 to 100 keV.
Do it. Second doping process and third doping
Low concentration impurity region overlapping the first conductive layer
1 × 10 for 436, 442 and 448¹⁸~ 5 × 10¹⁹/ c
m^ThreeImpurity element imparting n-type in the concentration range of
High concentration impurity regions 435, 438, 441, 444, 4
1 × 10 for 47¹⁹~ 2 × 10²⁰/cm^ThreeN-type in the concentration range of
Is added.

Of course, by selecting an appropriate acceleration voltage,
The low-concentration impurity region and the high-concentration impurity region formed by the second doping process and the third doping process are
It is also possible to carry out by a single doping process.

Next, after removing the mask made of resist, masks 450a to 450a made of resist are newly added.
After forming c, a fourth doping process is performed. This fourth
The impurity regions 451 and 453 to the semiconductor layer serving as the active layer of the p-channel TFT are added with an impurity element imparting a conductivity type opposite to the one conductivity type by the doping process.
456, 458, 460 and 461 are formed. Using the second conductive layers 428a to 432a as a mask for the impurity element, an impurity element imparting p-type is added to form an impurity region in a self-aligned manner. In this embodiment, the impurity regions 451,453～455,457,459,460 are formed by ion doping using diborane (B ₂ H _6). (FIG. 7B) In the fourth doping process, the semiconductor layer forming the n-channel TFT is partially covered with resist masks 450a to 450c. Phosphorus is added at different concentrations to the impurity regions 438 and 439 by the first to third doping treatments, and the concentration of the impurity element imparting p-type is set to 1 × 10 ¹⁹ to 2 in any of the regions. × 10 ²⁰ atoms / cm
By performing the doping treatment so as to be ³ , there is no problem because it functions as the source region and the drain region of the p-channel TFT.

Through the above steps, impurity regions are formed in the respective semiconductor layers.

Next, a mask 450a made of resist is used.
To 450c are removed to form a first interlayer insulating film 461. As the first interlayer insulating film 461, plasma C
Using a VD method or a sputtering method, a thickness of 100 to 200
The insulating film containing silicon is formed as nm. In this embodiment, a silicon oxynitride film with a thickness of 150 nm is formed by a plasma CVD method. Needless to say, the first interlayer insulating film 461 is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.

Then, heat treatment (at 300 to 550 ° C., 1 to 1)
By performing a heat treatment for 12 hours), hydrogenation can be performed. In this step, dangling bonds in the semiconductor layer are terminated by hydrogen contained in the first interlayer insulating film 461. The semiconductor layer can be hydrogenated regardless of the presence of the first interlayer insulating film. As other means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) or 300 to 300% in an atmosphere containing 3 to 100% hydrogen is used.
Heat treatment may be performed at 450 ° C. for 1 to 12 hours.

Next, a second interlayer insulating film 462 made of an inorganic insulating material or an organic insulating material is formed on the first interlayer insulating film 461. In this embodiment, the film thickness is 1.6 μm
Was formed, but the viscosity was 10 to 1000
cp, preferably 40 to 200 cp. Alternatively, a film whose surface is planarized may be used as the second interlayer insulating film 462.

Then, in drive circuit 506, wirings 464 to 468 electrically connected to the respective impurity regions, respectively.
To form Note that these wirings are made of a 50 nm thick T
A laminated film of an i film and a 500 nm-thick alloy film (an alloy film of Al and Ti) is formed by patterning. (FIG. 8
(A))

In the pixel portion 507, a pixel electrode 470, a gate wiring 469, and a connection electrode 468 are formed. With the connection electrode 468, the source wiring (the lamination of 443a and 443b) is electrically connected to the pixel TFT. Further, the gate wiring 469 is electrically connected to the gate electrode of the pixel TFT. In addition, the pixel electrode 4
In 70, an electrical connection is formed with the drain region 442 of the pixel TFT, and an electrical connection is formed with the semiconductor layer 458 functioning as one electrode forming a storage capacitor. In addition, as the pixel electrode 470, a material having excellent reflectivity, such as a film containing Al or Ag as a main component or a stacked film thereof, is preferably used.

Subsequently, laser light irradiation is performed from the back side of the substrate disclosed in the present invention to sufficiently recover the crystallinity of the semiconductor film, activate the impurity element, and reduce the contact resistance. Further, when irradiating the laser beam, the substrate may be heated to about 500 degrees. This makes it possible to perform laser light irradiation with a lower energy density. Thereby, the area of the laser beam on the irradiation surface can be increased, and the throughput of the process can be improved.

As described above, the n-channel TFT 50
1 and a CMOS circuit comprising a p-channel TFT 502;
And driving circuit 506 having n-channel TFT 503
And a pixel portion 507 having a pixel TFT 504 and a storage capacitor 505 can be formed over the same substrate. Thus, an active matrix substrate is completed.

The n-channel TFT 50 of the driving circuit 506
Reference numeral 1 denotes a low-concentration impurity region 4 which overlaps with a channel formation region 437 and a first conductive layer 428a which forms part of a gate electrode.
36 (GOLD region), a high-concentration impurity region 452 functioning as a source region or a drain region, and an impurity region 451 into which an impurity element imparting n-type and an impurity element imparting p-type are introduced. A p-channel TFT 502 connected to the n-channel TFT 501 with an electrode 466 to form a CMOS circuit includes a channel formation region 440, a high-concentration impurity region 454 functioning as a source region or a drain region, and an impurity element imparting n-type conductivity. And an impurity region 453 into which an impurity element imparting p-type is introduced. Also, an n-channel TFT 5
03 includes a channel formation region 443, a low-concentration impurity region 442 (GOLD region) overlapping with the first conductive layer 430a forming part of the gate electrode, a high-concentration impurity region 456 functioning as a source region or a drain region, and n There is an impurity region 455 into which an impurity element imparting a pattern and an impurity element imparting a p-type are introduced.

The pixel TFT 504 in the pixel portion includes a channel forming region 446, a low concentration impurity region 445 (LDD region) formed outside the gate electrode, a high concentration impurity region 458 functioning as a source region or a drain region, and n
There is an impurity region 457 into which an impurity element imparting a pattern and an impurity element imparting a p-type are introduced. Also,
An impurity element imparting n-type and an impurity element imparting p-type are added to a semiconductor layer functioning as one electrode of the storage capacitor 505. The storage capacitor 505 is formed using an electrode (a laminate of 432a and 432b) and a semiconductor layer using the insulating film 416 as a dielectric.

In the pixel structure of this embodiment, the ends of the pixel electrodes are arranged so as to overlap with the source lines so that the gap between the pixel electrodes is shielded from light without using a black matrix.

FIG. 9 is a top view of the pixel portion of the active matrix substrate manufactured in this embodiment. FIG.
9 are denoted by the same reference numerals. FIG.
A chain line AA ′ in (B) corresponds to a cross-sectional view cut along a chain line AA ′ in FIG. A dashed line BB ′ in FIG. 8B corresponds to a cross-sectional view taken along a dashed line BB ′ in FIG.

This embodiment can be freely combined with any one of Embodiments 1 to 3.

[Embodiment 5] In this embodiment, a process for fabricating a reflection type liquid crystal display device from the active matrix substrate fabricated in Embodiment 4 will be described below. Figure 10 for explanation
Is used.

First, after obtaining the active matrix substrate in the state of FIG. 8B according to the fourth embodiment, at least the pixel electrode 470 is formed on the active matrix substrate of FIG.
An alignment film 567 is formed thereon, and rubbing is performed. Note that in this embodiment, before forming the alignment film 567, a columnar spacer 572 for maintaining a substrate interval was formed at a desired position by patterning an organic resin film such as an acrylic resin film. Also, instead of columnar spacers,
Spherical spacers may be spread over the entire surface of the substrate.

Next, a counter substrate 569 is prepared. Next, the coloring layers 570 and 571 and the planarizing film 573 are formed over the counter substrate 569. The red coloring layer 570 and the blue coloring layer 572 are overlapped to form a light shielding portion. Alternatively, the light-blocking portion may be formed by partially overlapping the red coloring layer and the green coloring layer.

In this embodiment, the substrate shown in Embodiment 4 is used. Therefore, FIG. 9 shows a top view of the pixel portion of the fourth embodiment.
Then, at least a gap between the gate wiring 469 and the pixel electrode 470, a gap between the gate wiring 469 and the connection electrode 468,
It is necessary to shield the gap between the connection electrode 468 and the pixel electrode 470 from light. In this embodiment, the colored layers are arranged such that the light-shielding portion formed of the colored layers is overlapped at the positions where the light is to be shielded, and the opposing substrates are bonded to each other.

As described above, the number of steps can be reduced by shielding the gap between each pixel with the light-shielding portion composed of the stacked colored layers without forming a light-shielding layer such as a black mask.

Next, a counter electrode 576 made of a transparent conductive film was formed on at least the pixel portion on the flattening film 573, an alignment film 574 was formed on the entire surface of the counter substrate, and rubbing treatment was performed.

Then, the active matrix substrate on which the pixel portion and the driving circuit are formed and the counter substrate are sealed with a sealing material 568.
Paste in. A filler is mixed in the sealant 568, and the two substrates are bonded to each other at a uniform interval by the filler and the columnar spacer. afterwards,
A liquid crystal material 575 is injected between the two substrates, and completely sealed with a sealant (not shown). A known liquid crystal material may be used for the liquid crystal material 575. Thus, the reflection type liquid crystal display device shown in FIG. 10 is completed. Then, if necessary, the active matrix substrate or the opposing substrate is cut into a desired shape. Further, a polarizing plate (not shown) was attached only to the counter substrate. Then, using a known technique, F
PC was pasted.

This embodiment can be freely combined with any one of Embodiments 1 to 4, and the liquid crystal display panel manufactured as described above can be used as a display portion of various electronic devices. it can.

[Embodiment 6] In this embodiment, a process of manufacturing an active matrix liquid crystal display device different from that of Embodiment 5 from the active matrix substrate manufactured in Embodiment 4 will be described below. FIG. 11 is used for the description.

First, according to the fourth embodiment, after an active matrix substrate in the state shown in FIG. 8B is obtained, an alignment film 1067 is formed on the active matrix substrate shown in FIG. In this embodiment, the alignment film 1067 is used.
Before the formation of the substrate, a columnar spacer for maintaining a substrate interval was formed at a desired position by patterning an organic resin film such as an acrylic resin film. Instead of the columnar spacers, spherical spacers may be spread over the entire surface of the substrate.

Next, a counter substrate 1068 is prepared. The opposite substrate is provided with a color filter in which a coloring layer 1074 and a light-shielding layer 1075 are arranged corresponding to each pixel. Further, a light-blocking layer 1077 was provided also in a portion of the driver circuit. A flattening film 1076 covering the color filter and the light-shielding layer 1077 was provided. Next, a counter electrode 1069 made of a transparent conductive film was formed in the pixel portion over the planarization film 1076, an alignment film 1070 was formed over the entire surface of the counter substrate, and rubbing treatment was performed.

Then, the active matrix substrate on which the pixel portion and the driving circuit are formed and the opposing substrate are sealed with the sealing material 107.
Attach with 1 A filler is mixed in the sealant 1071, and the two substrates are bonded to each other at a uniform interval by the filler and the columnar spacer. After that, a liquid crystal material 1073 is injected between the two substrates, and completely sealed with a sealing agent (not shown). Liquid crystal material 107
For 3, a known liquid crystal material may be used. Thus, the active matrix type liquid crystal display device shown in FIG. 11 is completed. Then, if necessary, the active matrix substrate or the opposing substrate is cut into a desired shape. further,
A polarizing plate and the like were appropriately provided using a known technique. Then, an FPC was attached using a known technique.

This embodiment can be freely combined with any one of Embodiments 1 to 4. The liquid crystal display panel manufactured as described above can be used as a display portion of various electronic devices. it can.

[Embodiment 7] A CMOS circuit and a pixel portion formed by applying the present invention can be used for various electro-optical devices (such as an active matrix type liquid crystal display device). That is, the present invention can be applied to all electronic devices in which the electro-optical device is incorporated in the display unit.

Examples of such electronic devices include a video camera, a digital camera, a projector, a head mounted display (goggle type display), a car navigation, a car stereo, a personal computer, a portable information terminal (a mobile computer, a mobile phone, an electronic book, etc.). ). An example of them is shown in FIG.
This is shown in FIGS.

FIG. 12A shows a personal computer, which includes a main body 3001, an image input section 3002, and a display section 30.
03, a keyboard 3004 and the like. The display portion 3003 can be manufactured by applying the present invention.

FIG. 12B shows a video camera, which includes a main body 3101, a display section 3102, an audio input section 3103, operation switches 3104, a battery 3105, and an image receiving section 310.
6 and so on. The display portion 3102 can be manufactured by applying the present invention.

FIG. 12C shows a mobile computer (mobile computer), which includes a main body 3201, a camera section 3202, an image receiving section 3203, operation switches 3204, a display section 3205, and the like. Display unit 320 by applying the present invention
5 can be produced.

FIG. 12D shows a goggle type display having a main body 3301, a display section 3302, and an arm section 330.
3 and so on. The display portion 3302 can be manufactured by applying the present invention.

FIG. 12E shows a player using a recording medium on which a program is recorded (hereinafter, referred to as a recording medium), and includes a main body 3401, a display portion 3402, and a speaker portion 340.
3, a recording medium 3404, an operation switch 3405, and the like. This player uses a DVD (D
digital Versatile Disc), CD
And the like, it is possible to perform music appreciation, movie appreciation, games, and the Internet. Display unit 34 by applying the present invention
02 can be produced.

FIG. 12F shows a digital camera, which includes a main body 3501, a display section 3502, an eyepiece section 3503, operation switches 3504, an image receiving section (not shown), and the like. The display portion 3502 can be manufactured by applying the present invention.

FIG. 13A shows a front type projector, which includes a projection device 3601, a screen 3602, and the like. The present invention can be applied to the liquid crystal display device 3808 forming a part of the projection device 3601 and other driving circuits.

FIG. 13B shows a rear type projector, which includes a main body 3701, a projection device 3702, and a mirror 370.
3, including a screen 3704 and the like. The present invention relates to a projection device 2
The present invention can be applied to a liquid crystal display device 3808 which constitutes a part of the LCD 702 and other driving circuits.

FIG. 13C is a diagram showing an example of the structure of the projection devices 3601 and 3702 in FIGS. 13A and 13B. Projection devices 3601, 37
02 denotes a light source optical system 3801, mirrors 3802, 380
4 to 3806, dichroic mirror 3803, prism 3807, liquid crystal display device 3808, retardation plate 380
9. It is composed of a projection optical system 3810. Projection optical system 28
Reference numeral 10 denotes an optical system including a projection lens. In the present embodiment, an example of a three-plate type is shown, but there is no particular limitation, and for example, a single-plate type may be used. Further, the practitioner may appropriately provide an optical system such as an optical lens, a film having a polarizing function, a film for adjusting a phase difference, and an IR film in an optical path indicated by an arrow in FIG. Good.

FIG. 13D is a diagram showing an example of the structure of the light source optical system 3801 in FIG. 13C. In this embodiment, the light source optical system 3801 includes a reflector 2811, a light source 3812, a lens array 3813,
814, a polarization conversion element 2815, and a condenser lens 3816. Note that the light source optical system shown in FIG. 13D is an example and is not particularly limited. For example, a practitioner may appropriately provide an optical system such as an optical lens, a film having a polarizing function, a film for adjusting a phase difference, and an IR film in the light source optical system.

However, in the projector shown in FIG. 13, a case in which a transmissive electro-optical device is used is shown, and an application example in a reflective electro-optical device is not shown.

FIG. 14A shows a portable telephone, and a main body 39.
01, audio output unit 3902, audio input unit 3903, display unit 3904, operation switch 3905, antenna 3906
And so on. The present invention can be applied to the display portion 3904.

FIG. 14B shows a portable book (electronic book), which includes a main body 4001, display portions 4002 and 4003, a storage medium 4004, operation switches 4005, and an antenna 4006.
And so on. The present invention can be applied to the display portions 4002 and 4003.

FIG. 14C shows a display device,
01, a support 4102, a display unit 4103, and the like. The present invention can be applied to the display portion 4103. The display device of the present invention is particularly advantageous when the screen is enlarged,
This is advantageous for a display device having a diagonal of 10 inches or more (particularly 30 inches or more).

As described above, the applicable range of the present invention is extremely wide, and the present invention can be applied to electronic devices in various fields. Further, the electronic apparatus according to the present embodiment can be realized by using any combination of the embodiments 1 to 6.

By adopting the configuration of the present invention, the following basic significance can be obtained. (A) It is possible to sufficiently recover the crystallinity of the semiconductor film after the doping process, activate the impurity element, and reduce the contact resistance after the wiring is formed. (B) a conventional heat treatment after the doping process;
By performing the two steps of the heat treatment after the formation of the wiring in one step of irradiating laser light from the back surface side of the substrate after the formation of the wiring, the number of steps can be reduced as compared with the conventional case. As a result, the manufacturing cost can be reduced and the manufacturing yield can be improved. (C) A method that can manufacture a TFT having excellent electrical characteristics while satisfying the above advantages.

[Brief description of the drawings]

FIG. 1 illustrates an example of a method for manufacturing a TFT of the present invention.

FIG. 2A is a graph showing the transmittance of a 1737 glass substrate with respect to wavelength. (B) is a diagram showing the transmittance of a synthetic quartz glass substrate with respect to wavelength.

FIG. 3A is a graph showing the transmittance of an amorphous silicon film with respect to wavelength. FIG. 3B is a graph showing the transmittance of the crystalline silicon film with respect to the wavelength.

FIG. 4 illustrates an example of a method for manufacturing a TFT of the present invention.

FIG. 5 illustrates an example of a method for manufacturing a TFT of the present invention.

FIG. 6 is a cross-sectional view illustrating a manufacturing process of a pixel TFT and a TFT of a driver circuit.

FIG. 7 is a cross-sectional view illustrating a manufacturing process of a pixel TFT and a TFT of a driver circuit.

FIG. 8 is a cross-sectional view illustrating a manufacturing process of a pixel TFT and a TFT of a driver circuit.

FIG. 9 is a top view illustrating pixels in a pixel portion.

FIG. 10 is a cross-sectional view illustrating a manufacturing process of an active matrix liquid crystal display device.

FIG. 11 is a cross-sectional view illustrating a manufacturing process of an active matrix liquid crystal display device.

FIG. 12 illustrates an example of a semiconductor device.

FIG. 13 illustrates an example of a semiconductor device.

FIG. 14 illustrates an example of a semiconductor device.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/28 301 H01L 27/08 331E 5F052 21/768 29/78 627F 5F110 27/08 331 627G 29/786 627E 616L 21 / 90 A F term (reference) 2H092 HA04 JA24 JB56 KB04 KB25 MA04 MA05 MA08 MA17 MA26 MA27 MA30 NA21 NA27 NA28 NA29 PA10 PA11 RA10 4M104 AA09 BB08 BB17 BB30 BB32 CC05 DD37 DD42 DD45 DD65 FF08 FF13 GG20 A43A43A43 CA23 DA09 DA13 DB01 DB04 EA04 EA05 EA10 EB02 ED03 ED15 FA01 FA02 FB02 FB12 FB14 FB15 GB10 HA08 HA10 5F033 GG04 HH04 HH07 HH12 HH14 HH17 HH18 HH19 HH20 HH21 HH38 JJ01 JJ14 JJ01 JJ14 JJ07 JJ04 JJ14 JJ07 JJ14 JJ07 VV15 5F048 AA09 AC04 BA14 BA16 BB09 BF07 BF11 BF16 BG07 5F052 AA02 AA11 DA02 DB02 DB03 DB07 FA06 JA01 5F110 AA16 BB02 BB04 CC02 CC08 DD01 DD02 DD03 DD13 DD14 DD15 DD17 EE01 EE02 EE03 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE04 EE09 2 FF04 FF09 FF28 FF30 FF36 GG01 GG02 GG13 GG25 GG32 GG43 GG45 GG47 HJ01 HJ04 HJ12 HJ13 HJ23 HL02 HL03 HL04 HL06 HL07 HL08 HL11 HM15 NN03 NN22 NN23 NN27 Q11 Q28 Q03

Claims (34)

[Claims] A step of forming a first insulating film on a semiconductor film formed on a surface of the substrate; and forming a first conductive layer on the semiconductor film via the first insulating film. Process and
Selectively introducing an impurity element into the semiconductor film to form a channel formation region overlapping with the first conductive layer, and a source region and a drain region including the impurity region; Forming a second insulating film over the insulating film and the first conductive layer, and partially etching the first insulating film and the second insulating film or the second insulating film; Performing a step of exposing a part of the source region and the drain region;
Forming a second conductive layer in contact with a part of the source region or the drain region; and irradiating the semiconductor film with laser light from a back surface side of the substrate. Method for manufacturing the device. 2. a step of forming a semiconductor film on a surface of a substrate; and a step of crystallizing the semiconductor film by heat treatment.
Forming a first insulating film on the crystallized semiconductor film, forming a first conductive layer on the semiconductor film via the first insulating film, selectively forming the first conductive film on the semiconductor film; A step of introducing an impurity element to form a channel formation region overlapping with the first conductive layer, and a source region and a drain region formed of the impurity region; and forming the semiconductor film, the first insulating film, and the first Forming a second insulating film covering a conductive layer; and partially etching the first insulating film and the second insulating film or the second insulating film to form the source region and the second insulating film. Exposing a part of the drain region, forming a second conductive layer in contact with the source region or a part of the drain region, and irradiating the semiconductor film with laser light from the back surface side of the substrate And the process of The method for manufacturing a semiconductor device which is characterized in that. A step of forming a semiconductor film on a surface of the substrate; a step of introducing a metal element into the semiconductor film; a step of crystallizing the semiconductor film into which the metal element has been introduced by heat treatment; Forming a first insulating film on the converted semiconductor film; forming a first conductive layer on the semiconductor film via the first insulating film; and selectively forming impurities on the semiconductor film. A step of introducing an element to form a channel formation region overlapping with the first conductive layer, and a source region and a drain region formed of impurity regions; and forming the semiconductor film, the first insulating film, and the first conductive film. Forming a second insulating film covering the layer, and partially etching the first insulating film and the second insulating film or the second insulating film to form the source region and the second insulating film. Part of the drain region Exposing, forming a second conductive layer in contact with a part of the source region or the drain region, and irradiating the semiconductor film with laser light from the back surface side of the substrate. A method for manufacturing a semiconductor device, comprising: 4. A step of forming a first insulating film on a semiconductor film formed on a surface of a substrate, and forming a first conductive layer on the semiconductor film via the first insulating film. Process and
A step of selectively introducing an impurity element into the semiconductor film to form a channel formation region overlapping with the first conductive layer, and a source region and a drain region including the impurity region;
Forming a second insulating film covering the semiconductor film, the first insulating film, and the first conductive layer; hydrogenating the semiconductor film by heat treatment; A step of partially etching the second insulating film or the second insulating film to expose a part of the source region and the drain region; Second contact
Forming a conductive layer, and irradiating the semiconductor film with laser light from the back side of the substrate. 5. A step of forming a semiconductor film on a surface of a substrate, a step of crystallizing the semiconductor film by a first heat treatment, and a step of forming a first insulating film on the crystallized semiconductor film Forming a first conductive layer on the semiconductor film via a first insulating film; and selectively introducing an impurity element into the semiconductor film to form a channel formation region overlapping with the first conductive layer. Forming a source region and a drain region made of an impurity region;
Forming a second insulating film covering the first insulating film and the first conductive layer; hydrogenating the semiconductor film by a second heat treatment; A step of partially etching the insulating film or the second insulating film to expose a part of the source region and the drain region, and a step of contacting the source region or the part of the drain region. 2. A method for manufacturing a semiconductor device, comprising: forming a second conductive layer; and irradiating the semiconductor film with laser light from a back surface side of the substrate. 6. A step of forming a semiconductor film on a surface of a substrate, a step of introducing a metal element into the semiconductor film, and a step of crystallizing the semiconductor film into which the metal element has been introduced by a first heat treatment. And a first on the crystallized semiconductor film.
Forming a first conductive layer over the semiconductor film with a first insulating film interposed therebetween, and selectively introducing an impurity element into the semiconductor film to form a first conductive film. Forming a channel formation region overlapping with the conductive layer, a source region and a drain region including an impurity region, and forming a second insulating film covering the semiconductor film, the first insulating film, and the first conductive layer. Forming, hydrogenating the semiconductor film by a second heat treatment, and partially etching the first insulating film and the second insulating film or the second insulating film. Exposing a part of the source region and the drain region; forming a second conductive layer in contact with the source region or a part of the drain region; and forming the semiconductor film from a back side of the substrate. Laser light The method for manufacturing a semiconductor device characterized by having a step of irradiating. 7. A step of forming a first insulating film on a semiconductor film formed on a surface of a substrate, and forming a first conductive layer on the semiconductor film via the first insulating film. Process and
An impurity element is selectively introduced into the semiconductor film, and a channel formation region overlapping with the first conductive layer, a first impurity region overlapping part of the first conductive layer, and a second impurity region are formed. Forming a source region and a drain region of the semiconductor film, the first insulating film, and the first insulating film.
Forming a second insulating film covering the conductive layer of the first insulating film and the second insulating film,
Partially exposing the insulating film to expose a part of the source region and the drain region, and forming a second conductive layer in contact with the source region or the part of the drain region. And a step of irradiating the semiconductor film with laser light from the back side of the substrate. 8. A step of forming a semiconductor film on a surface of a substrate, a step of crystallizing the semiconductor film by heat treatment,
Forming a first insulating film on the crystallized semiconductor film, forming a first conductive layer on the semiconductor film via the first insulating film, selectively forming the first conductive film on the semiconductor film; A channel formation region overlapping with the first conductive layer by introducing an impurity element, a first impurity region overlapping part of the first conductive layer, and a source region and a drain region including a second impurity region. Forming the semiconductor film and the first
Forming a second insulating film covering the first insulating film and the first conductive layer, and partially selecting the first insulating film and the second insulating film or the second insulating film. Etching to partially expose the source region and the drain region, forming a second conductive layer in contact with the source region or a portion of the drain region, Irradiating the semiconductor film with laser light from the back surface side. 9. A step of forming a semiconductor film on a surface of a substrate, a step of introducing a metal element into the semiconductor film, a step of crystallizing the semiconductor film into which the metal element has been introduced by heat treatment, Forming a first insulating film on the converted semiconductor film, forming a first conductive layer on the semiconductor film via the first insulating film, selectively forming the first conductive film on the semiconductor film. A channel formation region overlapping with the first conductive layer by introducing an impurity element, a first impurity region overlapping part of the first conductive layer, and a source region and a drain region including a second impurity region. Forming a second insulating film covering the semiconductor film, the first insulating film, and the first conductive layer; and forming the first insulating film and the second insulating film; Alternatively, the second insulating film is partially etched. Performing a step of exposing a part of the source region and the drain region; a step of forming a second conductive layer in contact with the part of the source region or the drain region; and Irradiating the semiconductor film with laser light. 10. A step of forming a first insulating film on a semiconductor film formed on a surface of a substrate, and forming a first conductive layer on the semiconductor film via the first insulating film. And selectively introducing an impurity element into the semiconductor film,
Forming a channel formation region overlapping the first conductive layer, a first impurity region overlapping a part of the first conductive layer, and a source region and a drain region including a second impurity region; Forming a second insulating film covering the semiconductor film, the first insulating film, and the first conductive layer, hydrogenating the semiconductor film by a heat treatment; A step of partially etching the second insulating film or the second insulating film to expose a part of the source region and the drain region; Forming a second conductive layer, and irradiating the semiconductor film with laser light from the back side of the substrate. 11. A step of forming a semiconductor film on a surface of a substrate, a step of crystallizing the semiconductor film by a first heat treatment, and a step of forming a first insulating film on the crystallized semiconductor film. Forming a first conductive layer on the semiconductor film with the first insulating film interposed therebetween; and forming a channel overlapping with the first conductive layer by selectively introducing an impurity element into the semiconductor film. Forming a region, a first impurity region overlapping a part of the first conductive layer, and a source region and a drain region including a second impurity region; and forming the semiconductor film, the first insulating film, Forming a second insulating film covering the first conductive layer, hydrogenating the semiconductor film by a second heat treatment, the first insulating film and the second insulating film, Alternatively, the second insulating film is partially etched. Performing a step of exposing a part of the source region and the drain region; a step of forming a second conductive layer in contact with the part of the source region or the drain region; and Irradiating the semiconductor film with laser light. 12. A step of forming a semiconductor film on a surface of a substrate, a step of introducing a metal element into the semiconductor film,
Crystallizing the semiconductor film into which the metal element has been introduced by the heat treatment, forming a first insulating film on the crystallized semiconductor film, and forming the first insulating film on the semiconductor film. Forming a first conductive layer through a semiconductor layer, selectively introducing an impurity element into the semiconductor film, forming a channel formation region overlapping with the first conductive layer, and forming a portion of the first conductive layer. Forming an overlapping first impurity region and a source region and a drain region including a second impurity region; and forming a second insulating layer covering the semiconductor film, the first insulating film, and the first conductive layer. Forming a film, hydrogenating the semiconductor film by a second heat treatment, partially etching the first insulating film and the second insulating film, or partially etching the second insulating film. Line, said source region and said Exposing a part of the rain region, forming a second conductive layer in contact with a part of the source region or the drain region, and irradiating the semiconductor film with laser light from the back surface side of the substrate And a method for manufacturing a semiconductor device. 13. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film through an insulating film, selectively introducing an impurity element into the semiconductor film, and forming a channel formation region overlapping with the first conductive layer; a source region and a drain region including an impurity region; Forming a second insulating film on the semiconductor film into which the impurity element has been selectively introduced, and partially etching the second insulating film to form the source region. And exposing a part of the drain region, and forming a second conductive layer in contact with the source region or a part of the drain region,
Irradiating the semiconductor film with laser light from the back side of the substrate. 14. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film through an insulating film, crystallizing the semiconductor film by heat treatment, selectively introducing an impurity element into the crystallized semiconductor film, and overlapping with the first conductive layer. Forming a channel formation region, a source region and a drain region including an impurity region, forming a second insulating film on the semiconductor film into which the impurity element has been selectively introduced, Partially exposing the insulating film to expose a part of the source region and the drain region, and forming a second conductive layer in contact with the source region or the part of the drain region. And the back of the substrate Irradiating the semiconductor film with laser light from the surface side. 15. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film through an insulating film, introducing a metal element into the semiconductor film, crystallizing the semiconductor film by heat treatment, and selectively adding an impurity element to the crystallized semiconductor film. And forming a channel formation region overlapping with the first conductive layer and a source region and a drain region including an impurity region, and forming a second region on the semiconductor film into which the impurity element is selectively introduced. Forming a part of the source region or the drain region by partially etching the second insulating film to expose a part of the source region and the drain region; Contact with the first 2. A method for manufacturing a semiconductor device, comprising: forming a second conductive layer; and irradiating the semiconductor film with laser light from a back surface side of the substrate. 16. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film through an insulating film, selectively introducing an impurity element into the semiconductor film, and forming a channel formation region overlapping with the first conductive layer; a source region and a drain region including an impurity region; Forming a second insulating film on the semiconductor film into which the impurity element has been selectively introduced, hydrogenating the semiconductor film by a heat treatment, Partially etching the film to expose a part of the source region and the drain region, and forming a second conductive layer in contact with the source region or a part of the drain region; From the back side of the substrate Irradiating the semiconductor film with laser light. 17. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film via an insulating film; crystallizing the semiconductor film by a first heat treatment; selectively introducing an impurity element into the crystallized semiconductor film to form the first conductive film; Forming a channel formation region overlapping the layer, a source region and a drain region including an impurity region, and forming a second insulating film over the semiconductor film into which the impurity element is selectively introduced; Hydrogenating the semiconductor film by a second heat treatment, partially etching the second insulating film to expose a part of the source region and the drain region, Or the drain area A method for manufacturing a semiconductor device, comprising: a step of forming a second conductive layer in contact with part of a region; and a step of irradiating the semiconductor film with laser light from a back surface side of the substrate. 18. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming a first insulating layer on the first conductive layer. A step of forming a semiconductor film via an insulating film, a step of introducing a metal element into the semiconductor film, a step of crystallizing the semiconductor film by a first heat treatment, and a step of selectively crystallizing the semiconductor film. A step of introducing an impurity element to form a channel formation region overlapping the first conductive layer, and a source region and a drain region formed of the impurity region; and forming a channel region on the semiconductor film into which the impurity element is selectively introduced. Forming a second insulating film on the substrate, hydrogenating the semiconductor film by a second heat treatment, and partially etching the second insulating film to form the source region and the drain region. To expose part of Forming a second conductive layer in contact with a part of the source region or the drain region, and irradiating the semiconductor film with laser light from the back surface side of the substrate. Of manufacturing a semiconductor device. 19. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film with an insulating film interposed therebetween, selectively introducing an impurity element into the semiconductor film, forming a channel formation region overlapping the first conductive layer, and forming a part of the first conductive layer. Forming an overlapping first impurity region, a source region and a drain region including a second impurity region, and forming a second insulating film on the semiconductor film into which the impurity element is selectively introduced. A step of partially etching the second insulating film to expose part of the source region and the drain region; and a second step of contacting the source region or the part of the drain region. Forming a conductive layer; Irradiating the semiconductor film with laser light from the surface side. 20. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film through an insulating film, crystallizing the semiconductor film by heat treatment, selectively introducing an impurity element into the crystallized semiconductor film, and overlapping with the first conductive layer. Forming a channel formation region, a first impurity region overlapping a part of the first conductive layer, and a source region and a drain region including a second impurity region; and selectively introducing the impurity element Forming a second insulating film on the formed semiconductor film; partially etching the second insulating film to expose a part of the source region and the drain region; Of the source region or the drain region A method for manufacturing a semiconductor device, comprising: a step of forming a second conductive layer in contact with a part; and a step of irradiating a laser beam to the semiconductor film from a back surface side of the substrate. 21. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film through an insulating film, introducing a metal element into the semiconductor film, crystallizing the semiconductor film by heat treatment, and selectively adding an impurity element to the crystallized semiconductor film. And forming a channel formation region overlapping the first conductive layer, a first impurity region overlapping a part of the first conductive layer, and a source region and a drain region including a second impurity region. Performing a step of forming a second insulating film on the semiconductor film into which the impurity element has been selectively introduced, and partially etching the second insulating film to form the source region and the second insulating film. Exposing a part of the drain region; Forming a second conductive layer in contact with a part of the source region or the drain region; and irradiating the semiconductor film with laser light from the back surface side of the substrate. A method for manufacturing a semiconductor device. 22. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film with an insulating film interposed therebetween, selectively introducing an impurity element into the semiconductor film, forming a channel formation region overlapping the first conductive layer, and forming a part of the first conductive layer. Forming an overlapping first impurity region, a source region and a drain region including a second impurity region, and forming a second insulating film on the semiconductor film into which the impurity element has been selectively introduced. A step of hydrogenating the semiconductor film by a heat treatment, a step of partially etching the second insulating film to expose a part of the source region and the drain region, Or contact with a part of the drain region. A method for manufacturing a semiconductor device, comprising: a step of forming a second conductive layer to be touched; and a step of irradiating the semiconductor film with laser light from a back surface side of the substrate. 23. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming the first conductive layer on the first conductive layer. Forming a semiconductor film via an insulating film; crystallizing the semiconductor film by a first heat treatment; selectively introducing an impurity element into the crystallized semiconductor film to form the first conductive film; Forming a channel formation region overlapping the layer, a first impurity region overlapping a part of the first conductive layer, and a source region and a drain region including a second impurity region; Second on the semiconductor film introduced
Forming a second insulating film, hydrogenating the semiconductor film by a second heat treatment, and partially etching the second insulating film to form a part of the source region and the drain region. Exposing, forming a second conductive layer in contact with a part of the source region or the drain region, and irradiating the semiconductor film with laser light from the back surface side of the substrate. A method for manufacturing a semiconductor device, comprising: 24. A step of forming a first conductive layer on a substrate, a step of forming a first insulating film on the first conductive layer, and a step of forming a first insulating layer on the first conductive layer. A step of forming a semiconductor film via an insulating film, a step of introducing a metal element into the semiconductor film, a step of crystallizing the semiconductor film by a first heat treatment, and a step of selectively crystallizing the semiconductor film. A channel formation region overlapping with the first conductive layer by introducing an impurity element, a first impurity region overlapping part of the first conductive layer, and a source region and a drain region including a second impurity region. Forming a second insulating film on the semiconductor film into which the impurity element has been selectively introduced; hydrogenating the semiconductor film by a second heat treatment; 2 by partially etching the insulating film, Exposing a part of the source region and the drain region, forming a second conductive layer in contact with the source region or a part of the drain region, and forming a laser on the semiconductor film from the back side of the substrate. Irradiating light; and a method for manufacturing a semiconductor device. 25. The laser according to claim 1, wherein the laser beam is a YAG laser, a YVO ₄ laser, a YLF laser, a YAlO ₃ laser, a glass laser,
A method for manufacturing a semiconductor device, which is laser light oscillated from one kind selected from ruby laser and Ti: sapphire laser. 26. The method for manufacturing a semiconductor device according to claim 1, wherein a shape of the laser light irradiation surface or a vicinity thereof is linear. 27. The method for manufacturing a semiconductor device according to claim 1, wherein a wavelength of the laser light is 350 nm or more. 28. The method for manufacturing a semiconductor device according to claim 1, wherein a wavelength of the laser light is 400 nm or more. 29. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor film is a film containing silicon as a main component. 30. The semiconductor device according to claim 1, wherein the semiconductor film has a thickness of 25 to 25.
A method for manufacturing a semiconductor device, which is 100 nm. 31. The impurity element according to claim 1, wherein the impurity element in the source region and the drain region is an impurity element imparting n-type, an impurity element imparting p-type, or n-type. A method for manufacturing a semiconductor device, which is an impurity element to be imparted and an impurity element to impart p-type. 32. The method according to claim 1, wherein
In any one of the above, the source region and the drain
The impurity element concentration in the impurity region is 2 × 10 ²⁰/ C
m^ThreeManufacturing method of a semiconductor device characterized by the following:
Law. 33. The manufacturing method of a semiconductor device according to claim 1, wherein in the step of irradiating a laser beam from the back surface side of the substrate, the temperature of the substrate is 0 to 500 degrees. Method. 34. Claim 3 or Claim 6 or Claim 9 or Claim 12 or Claim 15 or Claim 18
Alternatively, in claim 21 or claim 24, the metal element is Fe, Co, Ni, Ru, Rh, Pd, Os,
A method for manufacturing a semiconductor device, comprising one or more elements selected from Ir, Pt, Cu, Ag, Au, Sn, and Sb.