JP2004006918A - Manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a superior semiconductor device. <P>SOLUTION: Using a laser processing system comprising a carrying-in/out chamber for carrying in/out a substrate, a carring chamber including a robot arm, a heating chamber for heating the substrate, and a laser irradiating chamber for irradiating the substrate with a laser beam while heating the substrate, the crystalline semiconductor film is illadiated with the laser beam while moving the laser beam so as to epitaxial grow the crystalline semiconductor film. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention disclosed in the present specification relates to a technique for performing various kinds of annealing on a semiconductor by laser light irradiation.
[Prior art]
[0002]
2. Description of the Related Art Conventionally, a technique of performing various annealing by irradiating a semiconductor with laser light has been known. For example, a technique in which an amorphous silicon film (a-Si film) formed on a glass substrate by a plasma CVD method is irradiated with a laser beam to transform the amorphous silicon film into a crystalline silicon film, Annealing technology and the like are known. As various annealing techniques using such laser light and an apparatus for irradiating laser light, there are techniques described in Japanese Patent Application Laid-Open No. 6-51238 by the present applicant.
[0003]
Since various annealing treatments by laser light do not thermally damage the underlying substrate, it is a useful technique when, for example, a heat-sensitive material such as a glass substrate is used as the substrate. However, there is a problem that it is difficult to always keep the annealing effect constant. In addition, when the amorphous silicon film is crystallized by laser light irradiation, it is difficult to always obtain the required good crystallinity, and a stable crystalline silicon film having better crystallinity is obtained. Technology was required.
[0004]
[Problems to be solved by the invention]
An object of the invention disclosed in this specification is to solve at least one or more of the following matters.
(1) A constant effect is always obtained in a technique of annealing a semiconductor by laser light irradiation.
(2) The crystallinity of the crystalline silicon film obtained by irradiating the amorphous silicon film with laser light is made higher.
[0005]
[Means for Solving the Problems]
One of the inventions disclosed herein is:
Performing a heat treatment to crystallize the amorphous silicon film;
Irradiating the silicon film crystallized in the step with a laser beam;
Has,
At the time of the laser beam irradiation, the sample is kept within ± 100 ° C. of the temperature at the time of the heat treatment.
[0006]
In the above structure, a temperature of 450 ° C. to 750 ° C. can be selected as the temperature during the heat treatment.
[0007]
The upper limit of this temperature is limited by the heat-resistant temperature of the substrate. When a glass substrate is used as the substrate, the upper limit is about 600 ° C. In consideration of productivity, it is desirable that this temperature be 550 ° C. or higher. Therefore, when a glass substrate is used, it is desirable to perform the heat treatment at a temperature of about 550 to 600 ° C.
[0008]
The heating temperature at the time of laser light irradiation is also preferably about 550 ° C. to 600 ° C., but heating from a temperature of about 450 ° C. is practical. Therefore, heating in a temperature range of 550 ° C. ± 100 ° C. is preferable.
[0009]
Also, other inventions disclosed in this specification are:
Crystallizing the amorphous silicon film by performing a heat treatment at a temperature of 600 ° C. or less;
Irradiating the silicon film crystallized in the step with a laser beam;
Has,
At the time of the laser beam irradiation, the sample is kept within ± 100 ° C. of the temperature at the time of the heat treatment.
[0010]
Also, other inventions disclosed in this specification are:
Performing a heat treatment to crystallize the amorphous silicon film;
Implanting impurity ions into at least a part of the silicon film crystallized in the step;
Irradiating the region into which the impurity ions have been implanted with laser light,
Has,
At the time of the laser beam irradiation, the sample is kept within ± 100 ° C. of the temperature at the time of the heat treatment.
[0011]
The configuration of another invention is as follows.
Performing a heat treatment to crystallize the amorphous silicon film;
Implanting impurity ions into at least a part of the silicon film crystallized in the step;
Irradiating the region into which the impurity ions have been implanted with laser light,
Has,
At the time of the laser beam irradiation, the sample is kept within ± 100 ° C. of the temperature at the time of the heat treatment.
[0012]
In another aspect of the invention,
A laser beam having a linear beam shape is sequentially moved from one side of the amorphous silicon film to the other and irradiated to the amorphous silicon film, and a region irradiated with the laser light is sequentially crystallized. In this method, the laser light irradiation is performed by heating the non-irradiated surface to a temperature of 450 ° C. or more.
[0013]
In the above configuration, by sequentially moving and irradiating the beam on the line, it is possible to effectively irradiate a laser beam to a required area. The condition of the temperature of the non-irradiated surface (heating temperature) is usually limited to about 600 ° C. However, this temperature is limited by the material of the substrate, and may be higher.
[0014]
【Example】
[Example 1]
In this embodiment, a laser processing apparatus used in carrying out the invention disclosed in this specification will be described. FIG. 1 shows a top view of the laser processing apparatus. FIG. 2 is a sectional view taken along the line AA ′ in FIG. FIG. 3 shows a cross-sectional view taken along line BB ′ of FIG. FIG. 4 is a block diagram of the laser processing apparatus.
[0015]
1 to 3, reference numeral 101 denotes a transfer chamber for loading and unloading a substrate (sample), in which a silicon film to be irradiated with laser light and a thin film transistor in a manufacturing process are formed. Substrate 100 is stored in a state of being stored in a multi-sheet cassette 105. When a substrate is taken in and out of the substrate loading / unloading chamber 101 from outside, the cassette 105 accommodating the substrate 100 is moved.
[0016]
Reference numeral 102 denotes a transfer chamber for transferring substrates in the apparatus, and includes a robot arm 106 for transferring substrates one by one. The robot arm 106 has a built-in heating means, and is designed to keep the temperature of the substrate (the temperature of the sample) constant even during the transfer of the substrate.
[0017]
Reference numeral 125 denotes alignment means for aligning the substrate, which has a function for accurately aligning the robot arm with the substrate.
[0018]
The chamber denoted by 103 is a chamber for irradiating the substrate with laser light. In this room, the laser light 108 emitted from the laser irradiation device 107 can be applied to the substrate placed on the stage 109 on which the substrate is placed, through the window 150 made of synthetic quartz. The stage 109 includes a unit for heating the substrate, and has a function of moving in a one-dimensional direction as indicated by an arrow.
[0019]
The laser irradiation device 107 has a function of oscillating a KrF excimer laser, for example, and incorporates an optical system as shown in FIG. By passing through the optical system shown in FIG. 5, the laser beam is shaped into a linear beam having a width of several millimeters to several centimeters and a length of several tens centimeters.
[0020]
The chamber indicated by 104 is a heating chamber for heating a substrate (sample), and accommodates a large number of substrates 100. A large number of substrates 100 are heated to a predetermined temperature by heating means (resistance heating means) 110. The substrate 100 is stored on a lift 111, and the lift 111 can be moved up and down when necessary, and the substrate 100 can be transferred by the robot arm 106 in the transfer chamber 102.
[0021]
Each chamber has a closed structure, and can be brought into a reduced pressure state or a high vacuum state by the exhaust systems 115 to 118. Each exhaust system is independently provided with a vacuum pump 119-122. Each chamber is provided with gas supply systems 112 to 114 and 121 for supplying a required gas (for example, an inert gas). Each chamber is provided with gate valves 122 to 124 so that the airtightness of each chamber is independently increased.
[0022]
[Example 2]
In this embodiment, an example in which a thin film transistor is manufactured using a laser treatment method disclosed in this specification will be described. FIG. 6 shows steps until a crystalline silicon film is obtained. First, a glass substrate 601 is prepared as shown in FIG. 1A, and a silicon oxide film 602 is formed as a base film on the surface of the glass substrate 601 to a thickness of 3000 ° by a sputtering method. As the glass substrate, for example, a Corning 7059 glass substrate can be used.
[0023]
Next, an amorphous silicon film (a-Si film) 603 is formed to a thickness of 500 ° by a plasma CVD method or a low pressure thermal CVD method. (FIG. 6 (A))
[0024]
Next, heat treatment is performed to crystallize the amorphous silicon film 603, so that a crystalline silicon film 607 is obtained. The heating temperature at this time may be about 450 ° C. to 750 ° C. However, in consideration of the problem of the heat resistance of the glass substrate, it is necessary to perform the heat treatment at a temperature of 600 ° C. or less. On the other hand, if the temperature is 500 ° C. or lower, the time required for crystallization becomes several tens hours or more, which is disadvantageous from the viewpoint of productivity. Here, in view of the problem of heat resistance of the glass substrate and the problem of the heat treatment time, heat treatment is performed at 550 ° C. for 4 hours. Thus, a crystalline silicon film 607 is obtained. (FIG. 6 (B))
[0025]
After the crystalline silicon film 607 is obtained by the heat treatment, the crystalline silicon film 607 is irradiated with a laser beam using the laser processing apparatus shown in FIGS. The outline of this laser processing step is shown below.
[0026]
First, a cassette 105 containing a large number of substrates (samples) having the state shown in FIG. 6C is stored in the substrate loading / unloading chamber 101. Each chamber is brought into a high vacuum state. The gate valves are all closed. Then, the gate valve 122 is opened, and one substrate 100 is taken out of the cassette 105 by the robot arm 106 and transferred to the transfer chamber 102. Then, the gate valve 124 is opened to transfer the substrate held by the robot arm 106 to the heating chamber 104. At this time, the heating chamber 104 is preheated so as to heat the substrate to a predetermined temperature.
[0027]
After carrying the substrate into the heating chamber 104, the next substrate is taken out of the cassette 105 again by the robot arm 106 and transferred to the heating chamber 104. By repeating the above operation a predetermined number of times, all of the substrates stored in the cassette 105 are stored in the heating chamber 104. After all the substrates stored in the cassette 105 are stored in the heating chamber 104, the gate valves 122 and 124 are closed.
[0028]
After a lapse of a predetermined time, the gate valve 124 is opened, and the substrate at a predetermined temperature (here, 500 ° C.) is drawn out to the transfer chamber 102 by the robot arm. At this time, the substrate is kept at 500 ° C. during the transfer by the heating means built in the robot arm. Then, the gate valve 124 is closed. Further, the gate valve 123 is opened, and the heated substrate is transferred to the chamber 103 for irradiating a laser beam. Then, the gate valve 123 is closed.
[0029]
A laser beam having a linear shape is used, and a predetermined area is irradiated with the laser beam by moving the substrate stage 109 in the width direction of the linear laser beam. Here, in the state of FIG. 6C, the substrate stage 109 is moved from the right end to the left end of the drawing so that the laser light is swept, and the laser light is irradiated. Here, the moving speed of the substrate stage 109 is 10 cm / min. In this embodiment, laser light irradiation is performed while the temperature of the substrate stage 109 is kept at 500 ° C.
[0030]
After the irradiation of the laser beam is completed, the gate valve 123 is opened, and the substrate held by the substrate holder is transferred to the transfer chamber 102 by the robot arm 106. Then, the gate valve 123 is closed. Then, the gate valve 122 is opened, and the substrate is stored in the cassette 105 in the loading / unloading chamber 101. Thereafter, the gate valve 122 closes.
[0031]
By repeating the above operation, laser light irradiation can be performed on all of the plurality of substrates housed in the heating chamber. After the irradiation of all the substrates with the laser beam is completed, the substrates housed in the cassette 105 are taken out of the apparatus from the loading / unloading chamber 101 for the substrates in each cassette.
[0032]
As shown in FIG. 6C, after the crystallinity of the crystalline silicon film is promoted by laser light irradiation, patterning is performed to form an active layer 701 of the thin film transistor. (FIG. 7A)
[0033]
Next, a silicon oxide film 702 functioning as a gate insulating film is formed to a thickness of 1000 ° by a sputtering method or a plasma CVD method. Next, an aluminum film containing 0.18 wt% of scandium is formed to a thickness of 6000 ° by a vapor deposition method. Then, a gate electrode 703 is formed by patterning. After the gate electrode 703 is formed, anodization is performed in an ethylene glycol solution containing 5% tartaric acid using the gate electrode 703 as an anode to form an aluminum oxide layer 704. The thickness of this oxide layer is about 2500 °. The thickness of the oxide layer 704 determines the length of the offset gate region formed in the subsequent impurity ion implantation step.
[0034]
Further, impurity ions (here, phosphorus ions) are implanted into the active layer by an ion doping method or a plasma doping method. At this time, the gate electrode 703 and the surrounding oxide layer 704 serve as a mask, and impurity ions are implanted into the regions 705 and 709. Thus, the source region 705 and the drain region 709 are formed in a self-aligned manner. Further, a channel forming region 707 and offset gate regions 706 and 708 are formed in a self-aligned manner.
[0035]
Then, laser light irradiation is performed to recrystallize the source region 705 and the drain region 709 and activate the implanted impurities. Intense light irradiation may be performed instead of the laser light irradiation. Irradiation of laser light to the source / drain regions performed here is performed by the apparatus shown in FIGS. The irradiation with the laser beam is performed while the substrate is heated to a temperature of 500 ° C.
[0036]
After the completion of annealing by laser light irradiation, a silicon oxide film 710 is formed as an interlayer insulating film to a thickness of 7000 ° by a plasma CVD method. Then, through a hole forming step, the source electrode 711 and the drain electrode 712 are formed using a suitable metal (for example, aluminum) or another suitable conductive material. Finally, heat treatment is performed at 350 ° C. for one hour in a hydrogen atmosphere, so that the thin film transistor illustrated in FIG. 7C is completed.
[0037]
[Example 3]
In this embodiment, the amorphous silicon film is irradiated with a laser beam to form a single crystal or a region having crystallinity that can be regarded as very close to a single crystal, and the region is used to activate the thin film transistor. Forming a layer.
[0038]
FIG. 8 shows a step of forming a single crystal or a region having crystallinity that can be regarded as very close to a single crystal. First, a silicon oxide film 602 is formed as a base film on a glass substrate 601 to a thickness of 3000 ° by a sputtering method. Further, an amorphous silicon film 603 is formed to a thickness of 500 ° by a plasma CVD method or a low pressure thermal CVD method. (FIG. 8A)
[0039]
Then, laser light irradiation is performed using the apparatus shown in FIGS. At the time of this laser light irradiation, the linear laser light 810 is moved (sweep) in the direction indicated by 811 so that the depth direction of the drawing becomes the longitudinal direction while the sample is heated to a temperature of 500 ° C. Let me do it. This moving speed is extremely slow, about 1 mm to 10 cm / min. At this time, in the region indicated by 812, a crystal nucleus or a crystallized region is formed by heating.
[0040]
When the linear laser light is moved as shown by 811, crystal growth is performed as shown by regions 812 to 813 into which a small amount of nickel is introduced. The crystal growth indicated by 813 proceeds from the region 812 where the crystal nucleus or crystal region is formed in a state that can be regarded as epitaxial growth or epitaxial growth. (FIG. 8 (B))
[0041]
This crystallization is performed by melting the region irradiated with the laser beam and growing the crystal epitaxially (or growth that can be regarded as epitaxial growth) from the previously crystallized region to the melted region. Then, by moving the linear laser light 810 as indicated by 811, the crystal growth proceeds sequentially as indicated by 813. Nickel, which is a metal element that promotes crystallization, segregates in the region where silicon is melted, so that as the crystallization shown by 813 proceeds, the nickel element concentrates at the tip where the crystal has grown. Therefore, the nickel concentration can be reduced in the central portion of the crystallized region 814. (FIG. 8 (C))
[0042]
Hereinafter, the laser beam irradiation step will be described. First, a cassette 105 containing a large number of substrates (samples) having the state shown in FIG. 8A is stored in the substrate loading / unloading chamber 101. Each chamber is brought into a high vacuum state. The gate valves are all closed. Then, the gate valve 122 is opened, and one substrate 100 is taken out of the cassette 105 by the robot arm 106 and transferred to the transfer chamber 102. Then, the gate valve 124 is opened to transfer the substrate held by the robot arm 106 to the heating chamber 104. At this time, the heating chamber 104 is preheated so as to heat the substrate to a predetermined temperature (500 ° C.).
[0043]
After carrying the substrate into the heating chamber 104, the next substrate is taken out of the cassette 105 again by the robot arm 106 and transferred to the heating chamber 104. By repeating the above operation a predetermined number of times, all of the substrates stored in the cassette 105 are stored in the heating chamber 104.
[0044]
Then, after a lapse of a predetermined time, the gate valve 124 is opened, and the substrate at a predetermined temperature (here, 500 ° C.) is drawn out to the transfer chamber 102 by the robot arm 106. At this time, the substrate is kept at 500 ° C. during the transfer by the heating means built in the robot arm. Then, the gate valve 124 is closed. Further, the gate valve 123 is opened, and the heated substrate is transferred to the chamber 103 for irradiating a laser beam. Then, the gate valve 123 is closed.
[0045]
A laser beam having a linear shape is used, and a predetermined area is irradiated with the laser beam by moving the substrate stage 109 in the width direction of the linear laser beam. Here, in the state of FIG. 8B, the laser light is irradiated by moving the substrate stage 109 so that the laser light is swept from the right side to the left side of the substrate in the drawing. Here, the moving speed of the substrate stage 109 is 1 cm / min. In this embodiment, laser light irradiation is performed while the temperature of the substrate stage 109 is kept at 500 ° C.
[0046]
After the irradiation of the laser beam is completed, the gate valve 123 is opened, and the substrate held by the substrate holder is transferred to the transfer chamber 102 by the robot arm 106. Then, the gate valve 123 is closed. Then, the gate valve 122 is opened, and the substrate is stored in the cassette 105 in the loading / unloading chamber 101. Thereafter, the gate valve 122 closes.
[0047]
By repeating the above operation, laser light irradiation can be performed on all of the plurality of substrates housed in the heating chamber. After the irradiation of all the substrates with the laser beam is completed, the substrates housed in the cassette 105 are taken out of the apparatus from the loading / unloading chamber 101 for the substrates in each cassette.
[0048]
In this embodiment, the time from when the first substrate is carried into the heating chamber 104 to when the last substrate is carried into the heating chamber 104, the first substrate is taken out of the heating chamber 104, and the laser light The time from when the substrate is transferred to the irradiation chamber 103 to when the last substrate is removed from the heating chamber 104 and when the substrate is transferred to the laser irradiation chamber 103 is started is the same. Thus, the time during which the substrate is held in the heating chamber can be the same for all substrates.
[0049]
An amorphous silicon film is formed on a substrate, and a crystal nucleus is easily generated at a temperature of 500 ° C. in a short time, and crystallization proceeds. Therefore, it is important that the time kept in the heating chamber 104 be the same as long as possible for all substrates in order to obtain a uniform crystalline silicon film.
[0050]
In this manner, a single crystal or a region 814 that can be regarded as a single crystal can be obtained. The region that can be considered as a single crystal is hydrogen ¹⁶ -10 ²⁰ cm ^-3 And has a structure in which internal defects are terminated by hydrogen.
[0051]
This region can be considered as a very large crystal grain. This area can also be larger.
[0052]
As illustrated in FIG. 8C, when a region 814 that can be regarded as a single crystal or a single crystal is obtained, an active layer of a thin film transistor is formed using the region. That is, patterning is performed to form an active layer indicated by 701 in FIG. At the time of this patterning, the extremely thin oxide film 802 is removed. Further, a silicon oxide film 702 functioning as a gate insulating film is formed to a thickness of 1000 ° by a sputtering method or a plasma CVD method. (FIG. 9A)
[0053]
Next, an aluminum film containing 0.18 wt% of scandium is formed to a thickness of 6000 ° by electron beam evaporation. Then, a gate electrode 703 is formed by patterning. After the gate electrode 703 is formed, anodization is performed in an ethylene glycol solution containing 5% tartaric acid using the gate electrode 703 as an anode to form an aluminum oxide layer 704. The thickness of this oxide layer is about 2500 °. The length of the offset gate region formed in a later impurity ion implantation step is determined by the thickness of the oxide layer 704. (FIG. 9 (B))
[0054]
Further, impurity ions (here, phosphorus ions) are implanted into the active layer by an ion doping method or a plasma doping method. At this time, the gate electrode 703 and the surrounding oxide layer 704 serve as a mask, and impurity ions are implanted into the regions 705 and 709. Thus, the source region 705 and the drain region 709 are formed in a self-aligned manner. Further, a channel forming region 707 and offset gate regions 706 and 708 are formed in a self-aligned manner. (FIG. 9 (C))
[0055]
Then, laser light irradiation is performed using the laser processing apparatus shown in FIGS. 1 to 3 to recrystallize the source region 705 and the drain region 709 and activate the implanted impurities.
[0056]
After the completion of annealing by laser light irradiation, a silicon oxide film 710 is formed as an interlayer insulating film to a thickness of 7000 ° by a plasma CVD method. Then, through a hole forming step, the source electrode 711 and the drain electrode 712 are formed using a suitable metal (for example, aluminum) or another suitable conductive material. Finally, heat treatment is performed at 350 ° C. for one hour in a hydrogen atmosphere, so that the thin film transistor illustrated in FIG. 9D is completed.
[0057]
In the thin film transistor described in this embodiment, the active layer is formed using a single crystal or a region that can be regarded as a single crystal. Therefore, a crystal grain boundary does not substantially exist in the active layer. A configuration that is not affected can be provided.
[0058]
The structure shown in this embodiment can be effectively used when forming a plurality of thin film transistors arranged in a line. For example, it can be used when a plurality of thin film transistors illustrated in FIG. 11D are simultaneously manufactured in one row in a depth direction of the drawing. Such a configuration in which a large number of thin film transistors are formed in a row can be used for a peripheral circuit (such as a shift register circuit) of a liquid crystal electro-optical device. Further, such a thin film transistor using a single crystal or a crystalline silicon film that can be regarded as a single crystal is useful for use in an analog buffer amplifier or the like.
[0059]
[Example 4]
This embodiment is an example in which a crystalline silicon film closer to a single crystal (having good crystallinity) is efficiently obtained by skillfully utilizing the mechanism of crystallization by laser light irradiation.
[0060]
FIG. 10 shows a manufacturing process of this embodiment. First, an underlying silicon oxide film 602 is formed on a glass substrate 601 to a thickness of 3000 ° by a sputtering method. Then, an amorphous silicon film 603 is formed to a thickness of 500 ° by a plasma CVD method or a low pressure thermal CVD method. Next, a mask is formed with a silicon oxide film. The silicon oxide film may be formed by a sputtering method or a plasma CVD method, but may be formed by using a coating liquid for forming a silicon oxide-based film. This is a type in which a solution state is solidified by heating at about 100 to 300 ° C., for example, an OCD (Ohka Diffusion Source) solution of Tokyo Ohka can be used. The silicon oxide film 815 has a slit shape having a longitudinal direction in the depth direction of the drawing in a region indicated by 802, and the surface of the amorphous silicon film 603 is exposed in the slit-shaped region 802. The slit-shaped region may be provided with a required length and a width of several μ to several tens μ (FIG. 10A).
[0061]
Then, as shown in FIG. 10B, a linear laser beam is irradiated while moving (sweeping) in the direction indicated by 811. This linear laser light is formed into a shape having a longitudinal direction in the depth direction of the drawing by using the optical system shown in FIG.
[0062]
The irradiation with the laser light 810 is performed by heating the sample to 500 ° C. and moving the sample very slowly at a speed of about 1 mm to 10 cm / min. At this time, in the region indicated by 812, a crystal nucleus or a crystallized region is formed by heating. The generation of the crystal nuclei and the formation of the crystallized region are due to the action of the nickel element. The laser light irradiation step is the same as in the third embodiment.
[0063]
When the linear laser light is irradiated while being moved as indicated by reference numeral 811, the region indicated by reference numeral 812 is rapidly cooled after the irradiation of the laser light because the silicon oxide film does not exist on the surface. Since the amorphous silicon film to which the laser beam has moved has been sandwiched between the silicon oxide films on the upper and lower sides, there is no escape for heat, and the film is instantaneously heated to a high temperature. That is, there are a cold region 812 having a crystal structure and a region in a molten state with high heat. Naturally, a sharp temperature gradient occurs between the two. Crystal growth is promoted by the action of this temperature gradient, and crystal growth that can be regarded as epitaxial growth proceeds as indicated by 813. Then, a single crystal or a region 814 that can be regarded as a single crystal can be obtained.
[0064]
The structure as shown in this embodiment can realize the easiness of the start of the growth at the growth start point, and can form a single crystal or a region which can be regarded as a single crystal, though partially.
[0065]
Thus, a single crystal or a region which can be regarded as a single crystal as indicated by reference numeral 814 in FIG. 10C can be obtained. This single crystal or a region that can be regarded as a single crystal can be formed over a length of several tens of μm or more, and a single crystal thin film transistor can be formed using this region.
[0066]
[Example 5]
FIG. 11 shows an example in which a more advanced active matrix liquid crystal display system is constructed using the invention disclosed in this specification. In the example of FIG. 11, a semiconductor chip mounted on a main board of an ordinary computer is fixed on at least one substrate of a liquid crystal display having a configuration in which a liquid crystal is sandwiched between a pair of substrates, so that miniaturization is achieved. This is an example of weight reduction and thinning.
[0067]
Hereinafter, FIG. 11 will be described. The substrate 15 is also a substrate of a liquid crystal display, on which an active matrix circuit 14 in which a number of pixels each having a TFT 11, a pixel electrode 12, and an auxiliary capacitor 13 are formed, an X decoder / driver for driving the active matrix circuit 14, and Y A decoder / driver and an XY branch circuit are formed by TFTs. Of course, the invention disclosed in this specification can be used as a TFT.
[0068]
Then, another chip is mounted on the substrate 15. These chips are connected to circuits on the substrate 15 by means such as a wire bonding method and a COG (chip-on-glass) method. In FIG. 11, the correction memory, the memory, the CPU, and the input port are chips mounted in this way, and various other chips may be mounted.
[0069]
In FIG. 11, an input port is a circuit that reads a signal input from the outside and converts the signal into an image signal. The correction memory is a memory unique to a panel for correcting an input signal or the like in accordance with the characteristics of the active matrix panel. In particular, this correction memory has information unique to each pixel as a non-volatile memory, and is used for individual correction. That is, when a pixel of the electro-optical device has a point defect, a signal corrected in accordance with the defect is sent to pixels around the point to cover the point defect and make the defect inconspicuous. Alternatively, when a pixel is darker than the surrounding pixels, a larger signal is sent to the pixel so as to have the same brightness as the surrounding pixels. Since the pixel defect information differs for each panel, the information stored in the correction memory differs for each panel.
[0070]
The functions of the CPU and the memory are the same as those of an ordinary computer. In particular, the memory has an image memory corresponding to each pixel as a RAM. These chips are all CMOS type.
[0071]
Further, at least a part of a required integrated circuit may be constituted by the invention disclosed in this specification, and the thickness of the system may be further increased.
As described above, even a CPU and a memory are formed on a liquid crystal display substrate, and configuring an electronic device such as a simple personal computer with one substrate reduces the size of a liquid crystal display system and expands its application range. Very useful for.
[0072]
A thin film transistor using the invention disclosed in this specification can be used for the circuit illustrated in FIG. 11 or a necessary circuit. In particular, it is useful to use a thin film transistor manufactured using a single crystal or a region which can be regarded as a single crystal for an analog buffer or other circuits.
[0073]
【The invention's effect】
The crystalline silicon film crystallized by the introduction of the metal element that promotes crystallization and the heat treatment is heated to a temperature within ± 100 ° C. of the temperature at the time of the previous heat treatment. By performing the annealing by irradiation, the crystallinity can be further improved, and a silicon film having good crystallinity can be obtained.
[0074]
In addition, impurity ions are implanted into the crystalline silicon film crystallized by the introduction of a metal element that promotes crystallization and the heat treatment, and the temperature is further reduced to within ± 100 ° C. of the temperature at the time of the previous heat treatment. By performing annealing by laser light irradiation in a state where the sample is heated, the impurity region can be effectively formed.
[0075]
Further, by irradiating a linear laser beam from one side of the amorphous silicon film to the other while heating to a temperature of 450 ° C. or more, crystal growth can be performed sequentially according to the laser beam irradiation. , A single crystal or a region that can be regarded as a single crystal can be formed.
[0076]
In particular, a region having higher crystallinity (a region almost regarded as a single crystal) can be easily formed by irradiating a laser beam as described above in a state where a metal element which promotes crystallization is introduced into the amorphous silicon film. can do. At this time, by irradiating the linear laser light while moving it, the metal element can be segregated at the end point of the crystal growth, and the concentration of the metal element in the crystallized region can be minimized.
[Brief description of the drawings]
FIG. 1 is a top view of a laser processing apparatus.
FIG. 2 is a sectional view of a laser processing apparatus.
FIG. 3 is a sectional view of a laser processing apparatus.
FIG. 4 is a block diagram of a laser processing apparatus.
FIG. 5 is a diagram showing a laser optical system of the laser processing apparatus.
FIG. 6 is a process chart for manufacturing a crystalline silicon film on a substrate.
FIG. 7 is a manufacturing process diagram of a thin film transistor.
FIG. 8 is a process chart for manufacturing a crystalline silicon film over a substrate.
FIG. 9 is a manufacturing process view of a thin film transistor.
FIG. 10 is a process chart for manufacturing a crystalline silicon film over a substrate.
FIG. 11 is a diagram schematically showing a liquid crystal display system.
[Explanation of symbols]
601 glass substrate
602 silicon oxide film (underlying film)
603 amorphous silicon film
607 crystalline silicon film
701 Active layer
702 Silicon oxide film (gate insulating film)
703 Gate electrode mainly composed of aluminum
704 anodic oxide layer
705 source area
706 offset gate area
707 Channel formation area
708 offset gate area
709 Drain region
710 interlayer insulating film
711 Source electrode
712 drain electrode
802 Exposed area
803 Crystal growth direction
801 resist mask
810 Linear laser light
811 Moving direction of laser beam on line
812 Crystal nucleus or crystalline region
814 Single crystal or region regarded as single crystal
815 Mask composed of silicon oxide film

Claims (3)

Forming an amorphous semiconductor film above the substrate;
A step of forming a crystalline semiconductor film by introducing a metal element that promotes crystallization into the amorphous semiconductor film and then performing crystallization by heating the amorphous semiconductor film;
Irradiating the crystalline semiconductor film with laser light,
Has,
Irradiating the crystalline semiconductor film with laser light,
Transferring the substrate from the loading and unloading chamber to the transfer chamber,
Transferring the substrate from the transfer chamber to a heating chamber,
After heating the substrate in the heating chamber, transferring the substrate to the transfer chamber,
Transferring the substrate from the transfer chamber to a laser irradiation chamber,
After irradiating the crystalline semiconductor film on the substrate while moving the laser light while heating the substrate in the laser irradiation chamber, transferring the substrate to the transfer chamber,
Transferring the substrate from the transfer chamber to the loading and unloading chamber,
Has,
The transfer is performed by a robot arm provided in the transfer chamber,
The loading / unloading chamber, the transfer chamber, the heating chamber, and the laser irradiation chamber are each in a high vacuum state,
A method for manufacturing a semiconductor device, characterized in that the crystalline silicon film is irradiated with the laser light while moving the crystalline semiconductor film, whereby the crystalline silicon film is epitaxially grown. In claim 1,
The method for manufacturing a semiconductor device, wherein the laser light is a linear laser light. In claim 1 or 2,
The method for manufacturing a semiconductor device, wherein a temperature of the substrate is kept within ± 100 ° C. of a heating temperature for heating the amorphous semiconductor film when the laser light is applied.

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