JP4268457B2 - Method for manufacturing semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention disclosed in this specification relates to a technique for performing various annealings on a semiconductor by laser light irradiation.
[Prior art]
[0002]
2. Description of the Related Art Conventionally, techniques for performing various annealings by irradiating a semiconductor with laser light are known. For example, a technique for transforming an amorphous silicon film (a-Si film) formed on a glass substrate by a plasma CVD method into a crystalline silicon film by irradiating a laser beam, or after impurity ion implantation Annealing technology and the like are known. As various annealing techniques using such laser light and apparatuses for irradiating laser light, there are techniques described in JP-A-6-51238 by the present applicant.
[0003]
Various annealing treatments with laser light do not cause thermal damage to the underlying substrate, and are useful techniques 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 make 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 with better crystallinity is obtained. Technology was sought.
[0004]
[Problems to be solved by the invention]
An object of the invention disclosed in this specification is to solve at least one of the following matters.
(1) A constant effect is always obtained in the annealing technique for semiconductors 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 in this specification is:
Applying heat treatment to crystallize the amorphous silicon film;
Irradiating laser light to the silicon film crystallized in the step;
Have
When the laser light is irradiated, the sample is kept within ± 100 ° C. of the temperature during the heat treatment.
[0006]
In the above configuration, 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, and when a glass substrate is used as the substrate, the upper limit is about 600 ° C. In consideration of productivity, this temperature is desirably 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 it becomes practical by heating from a temperature of about 450 ° C. Therefore, heating in the temperature range of 550 ° C. ± 100 ° C. is preferable.
[0009]
In addition, other inventions disclosed in this specification are:
Applying heat treatment at a temperature of 600 ° C. or lower to crystallize the amorphous silicon film;
Irradiating laser light to the silicon film crystallized in the step;
Have
When the laser light is irradiated, the sample is kept within ± 100 ° C. of the temperature during the heat treatment.
[0010]
In addition, other inventions disclosed in this specification are:
Applying heat treatment to crystallize the amorphous silicon film;
A step of implanting impurity ions into at least a part of the silicon film crystallized in the step;
Irradiating the region where the impurity ions are implanted with laser light;
Have
When the laser light is irradiated, the sample is kept within ± 100 ° C. of the temperature during the heat treatment.
[0011]
The configuration of another invention is as follows:
Applying heat treatment to crystallize the amorphous silicon film;
A step of implanting impurity ions into at least a part of the silicon film crystallized in the step;
Irradiating the region where the impurity ions are implanted with laser light;
Have
When the laser light is irradiated, the sample is kept within ± 100 ° C. of the temperature during the heat treatment.
[0012]
In another aspect of the invention,
Amorphous silicon film is irradiated with a laser beam having a linear beam shape by sequentially moving from one side of the amorphous silicon film to the other, and the regions irradiated with the laser light are sequentially crystallized. The laser beam irradiation is performed by heating the non-irradiated surface to a temperature of 450 ° C. or higher.
[0013]
In the above-described configuration, by sequentially moving and irradiating the beam on the line, it is possible to effectively irradiate the necessary region with the laser beam. Further, the condition of the temperature (heating temperature) of the non-irradiated surface 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 when carrying out the invention disclosed in this specification is shown. FIG. 1 shows a top view of the laser processing apparatus. FIG. 2 is a cross-sectional view taken along the line AA ′ in FIG. FIG. 3 shows a cross-sectional view taken along the line BB ′ of FIG. A block diagram of this laser processing apparatus is shown in FIG.
[0015]
In FIG. 1 to FIG. 3, reference numeral 101 denotes a transfer carry-in chamber for carrying in and out a substrate (sample), in which a silicon film to be irradiated with laser light and a thin film transistor in the middle of the manufacturing process are formed. The substrate 100 is stored in a state of being stored in a multi-sheet cassette 105. When loading / unloading a substrate into / from the substrate loading / unloading chamber 101 from outside, the cassette 105 in which the substrate 100 is stored 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 incorporates a heating means, and is devised to keep the substrate temperature (sample temperature) constant even during transfer of the substrate.
[0017]
Reference numeral 125 denotes an alignment means for aligning the substrate, and has a function for accurately aligning the robot arm and the substrate.
[0018]
A chamber 103 is a chamber for irradiating the substrate with laser light. In this chamber, the laser beam 108 irradiated from the laser irradiation device 107 can be irradiated onto the substrate disposed on the stage 109 on which the substrate is placed through the synthetic quartz window 150. The stage 109 includes a means 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, for example, a KrF excimer laser and incorporates an optical system as shown in FIG. By passing through the optical system shown in FIG. 5, the laser beam is formed into a linear beam having a width of several millimeters to several centimeters and a length of several tens of centimeters.
[0020]
A chamber 104 is a heating chamber for heating the substrate (sample), and stores a large number of substrates 100. A large number of substrates 100 are heated to a predetermined temperature by a heating means (resistance heating means) 110. The substrate 100 is housed on a lift 111, and the substrate 111 can be transported by the robot arm 106 in the transport chamber 102 by raising and lowering the lift 111 when necessary.
[0021]
Each chamber has a sealed 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 vacuum pumps 119 to 122. Each chamber is provided with gas supply systems 112 to 114 and 121 for supplying a necessary gas (for example, an inert gas). Each chamber is provided with gate valves 122 to 124, and is configured to independently increase the airtightness of each chamber.
[0022]
[Example 2]
In this example, an example in which a thin film transistor is manufactured using the laser treatment method disclosed in this specification will be described. FIG. 6 shows a process until a crystalline silicon film is obtained. First, as shown in (A), a glass substrate 601 is prepared, and a silicon oxide film 602 is formed as a base film on the surface thereof to a thickness of 3000 mm using a sputtering method. For example, a Corning 7059 glass substrate can be used as the glass substrate.
[0023]
Next, an amorphous silicon film (a-Si film) 603 is formed to a thickness of 500 mm by plasma CVD or low pressure thermal CVD. (Fig. 6 (A))
[0024]
Next, heat treatment is performed to crystallize the amorphous silicon film 603, whereby a crystalline silicon film 607 is obtained. The heating temperature at this time may be about 450 ° C. to 750 ° C. However, when considering the problem of heat resistance of the glass substrate, it is necessary to carry out at a temperature of 600 ° C. or lower. If the temperature is 500 ° C. or lower, the time required for crystallization is several tens of hours or more, which is disadvantageous from the viewpoint of productivity. Here, in view of the heat resistance problem of the glass substrate and the heat treatment time, the heat treatment is performed at 550 ° C. for 4 hours. Thus, a crystalline silicon film 607 is obtained. (Fig. 6 (B))
[0025]
When the crystalline silicon film 607 is obtained by heat treatment, laser light is irradiated using the laser processing apparatus shown in FIGS. 1 to 3 to further promote crystallization of the crystalline silicon film 607. The outline of this laser treatment process is shown below.
[0026]
First, a cassette 105 in which a large number of substrates (samples) having the state shown in FIG. 6C are stored is stored in a substrate loading / unloading chamber 101. Then, each chamber is brought into a high vacuum state. All gate valves are closed. Then, the gate valve 122 is opened, and one substrate 100 is taken out from the cassette 105 by the robot arm 106 and transferred to the transfer chamber 102. Then, the gate valve 124 is opened, and the substrate held by the robot arm 106 is transferred to the heating chamber 104. At this time, the heating chamber 104 is heated in advance 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 from the cassette 105 by the robot arm 106 again and transferred to the heating chamber 104. By repeating the above operation a predetermined number of times, all 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]
Then, after a predetermined time has elapsed, the gate valve 124 is opened, and the substrate having a predetermined temperature (here, 500 ° C.) is drawn out into 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 laser light. Then, the gate valve 123 is closed.
[0029]
A laser beam having a linear shape is used, and the substrate stage 109 is moved in the width direction of the linear laser beam to irradiate a predetermined area with the laser beam. Here, in the state of FIG. 6C, the substrate stage 109 is moved so that the laser light is swept from the right end of the substrate to the left end of the drawing, 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 with the temperature of the substrate stage 109 maintained at 500 ° C.
[0030]
After the end of laser light irradiation, 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 is closed.
[0031]
By repeating the above operation, it is possible to irradiate laser light to all of the plurality of substrates housed in the heating chamber. After the irradiation of the laser beam to all the substrates is completed, the substrates stored in the cassette 105 are taken out from the loading / unloading chamber 101 for each cassette substrate to the outside of the apparatus.
[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. 7 (A))
[0033]
Next, a silicon oxide film 702 functioning as a gate insulating film is formed to a thickness of 1000 mm by sputtering or plasma CVD. Next, an aluminum film containing 0.18 wt% scandium is formed to a thickness of 6000 mm by vapor deposition. A gate electrode 703 is formed by patterning. When the gate electrode 703 is formed, anodization is performed using the gate electrode 703 as an anode in an ethylene glycol solution containing 5% tartaric acid to form an aluminum oxide layer 704. The thickness of this oxide layer is about 2500 mm. The thickness of the oxide layer 704 determines the length of the offset gate region formed in a subsequent impurity ion implantation step.
[0034]
Further, impurity ions (here, phosphorus ions) are implanted into the active layer by ion doping or plasma doping. At this time, impurity ions are implanted into the regions 705 and 709 using the gate electrode 703 and the surrounding oxide layer 704 as a mask. Thus, the source region 705 and the drain region 709 are formed in a self-aligning manner. Further, a channel formation 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. Instead of this laser light irradiation, strong light irradiation may be performed. Irradiation of the laser beam to the source / drain region performed here is performed by the apparatus shown in FIGS. In this laser light irradiation, the substrate is heated to a temperature of 500.degree.
[0036]
After completion of annealing by laser light irradiation, a silicon oxide film 710 is formed as an interlayer insulating film to a thickness of 7000 mm by plasma CVD. Then, a source electrode 711 and a drain electrode 712 are formed using an appropriate metal (for example, aluminum) or other appropriate conductive material through a perforating process. Finally, heat treatment at 350 ° C. is performed in a hydrogen atmosphere for 1 hour, whereby the thin film transistor illustrated in FIG. 7C is completed.
[0037]
Example 3
In this embodiment, the amorphous silicon film is irradiated with laser light to form a single crystal or a region having crystallinity that can be regarded as very close to a single crystal, and the active region of the thin film transistor is utilized using the region. A layer is formed.
[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 mm by sputtering. Further, an amorphous silicon film 603 is formed to a thickness of 500 mm by plasma CVD or reduced pressure thermal CVD. (Fig. 8 (A))
[0039]
Then, laser light irradiation is performed using the apparatus shown in FIGS. When irradiating this laser beam, the linear laser beam 810 is moved in the direction indicated by 811 (sweep) so that the depth direction in the drawing is the longitudinal direction while the sample is heated to a temperature of 500 ° C. I will let you. 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 beam is moved as indicated by 811, crystal growth is performed as indicated by regions 812 to 813 in which a small amount of nickel is introduced. The crystal growth indicated by 813 proceeds from a region 812 where crystal nuclei or crystal regions are 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 light and epitaxially growing the crystal from the previously crystallized region to the melted region (or growth that can be regarded as epitaxial growth). Then, by moving the linear laser beam 810 as indicated by 811, this crystal growth proceeds sequentially as indicated by 813. Further, since nickel, which is a metal element that promotes crystallization, segregates in a region where silicon is melted, as the crystallization indicated by 813 progresses, the nickel element concentrates at the tip of the crystal growth. Accordingly, the nickel concentration can be lowered in the central portion of the crystallized region 814. (Fig. 8 (C))
[0042]
The laser light irradiation process will be described below. First, a cassette 105 storing a large number of substrates (samples) having the state shown in FIG. 8A is stored in a substrate loading / unloading chamber 101. Then, each chamber is brought into a high vacuum state. All gate valves are closed. Then, the gate valve 122 is opened, and one substrate 100 is taken out from the cassette 105 by the robot arm 106 and transferred to the transfer chamber 102. Then, the gate valve 124 is opened, and the substrate held by the robot arm 106 is transferred to the heating chamber 104. At this time, the heating chamber 104 is heated in advance 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 from the cassette 105 by the robot arm 106 again and transferred to the heating chamber 104. By repeating the above operation a predetermined number of times, all the substrates stored in the cassette 105 are stored in the heating chamber 104.
[0044]
Then, after a predetermined time has elapsed, the gate valve 124 is opened, and the substrate that has reached a predetermined temperature (here, 500 ° C.) is pulled 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 laser light. Then, the gate valve 123 is closed.
[0045]
A laser beam having a linear shape is used, and the substrate stage 109 is moved in the width direction of the linear laser beam to irradiate a predetermined area with the laser beam. Here, in the state of FIG. 8B, the substrate stage 109 is moved so that the laser beam is swept from the right side to the left side of the substrate in the drawing, and the laser beam is irradiated. Here, the moving speed of the substrate stage 109 is 1 cm / min. In this embodiment, laser light irradiation is performed with the temperature of the substrate stage 109 maintained at 500 ° C.
[0046]
After the end of laser light irradiation, 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 is closed.
[0047]
By repeating the above operation, it is possible to irradiate the laser light to all of the plurality of substrates housed in the heating chamber. After the irradiation of the laser beam to all the substrates is completed, the substrates stored in the cassette 105 are taken out from the loading / unloading chamber 101 for each cassette substrate to the outside of the apparatus.
[0048]
In this embodiment, the time from when the first substrate is carried into the heating chamber 104 until the last substrate is carried into the heating chamber 104, the first substrate is taken out of the heating chamber 104, and laser light The time from when the substrate is started to be transferred to the chamber 103 to be irradiated until the last substrate is taken out of the heating chamber 104 and this substrate is started to be transferred to the chamber 103 to be irradiated with laser light is the same. Thus, the time for which the substrate is held in the heating chamber can be made the same for all the substrates.
[0049]
An amorphous silicon film is formed on the substrate, and crystal nuclei are easily generated at a temperature of 500 ° C. in a short time, and crystallization proceeds. Therefore, it is important for obtaining a uniform crystalline silicon film that the time held in the heating chamber 104 be the same as much as possible in all the substrates.
[0050]
In this manner, a region 814 that can be regarded as a single crystal or a single crystal can be obtained. This region that can be regarded as a single crystal has 10% hydrogen. ¹⁶ -10 ²⁰ cm ^-3 It has a structure in which internal defects are terminated with hydrogen.
[0051]
This region can be regarded as a very large crystal grain. This area can also be made larger.
[0052]
When a region 814 that can be regarded as a single crystal or a single crystal is obtained as shown in FIG. 8C, an active layer of the thin film transistor is formed using this region. That is, patterning is performed to form an active layer indicated by reference numeral 701 in FIG. Further, during this patterning, the ultrathin oxide film 802 is removed. Further, a silicon oxide film 702 functioning as a gate insulating film is formed to a thickness of 1000 mm by sputtering or plasma CVD. (Fig. 9 (A))
[0053]
Next, an aluminum film containing 0.18 wt% scandium is formed to a thickness of 6000 mm by electron beam evaporation. A gate electrode 703 is formed by patterning. When the gate electrode 703 is formed, anodization is performed using the gate electrode 703 as an anode in an ethylene glycol solution containing 5% tartaric acid to form an aluminum oxide layer 704. The thickness of this oxide layer is about 2500 mm. The thickness of the oxide layer 704 determines the length of the offset gate region formed in a later impurity ion implantation step. (Fig. 9 (B))
[0054]
Further, impurity ions (here, phosphorus ions) are implanted into the active layer by ion doping or plasma doping. At this time, impurity ions are implanted into the regions 705 and 709 using the gate electrode 703 and the surrounding oxide layer 704 as a mask. Thus, the source region 705 and the drain region 709 are formed in a self-aligning manner. Further, a channel formation region 707 and offset gate regions 706 and 708 are formed in a self-aligned manner. (Figure 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 completion of annealing by laser light irradiation, a silicon oxide film 710 is formed as an interlayer insulating film to a thickness of 7000 mm by plasma CVD. Then, a source electrode 711 and a drain electrode 712 are formed using an appropriate metal (for example, aluminum) or other appropriate conductive material through a perforating process. Finally, a heat treatment at 350 ° C. is performed for 1 hour in a hydrogen atmosphere, whereby the thin film transistor illustrated in FIG. 9D is completed.
[0057]
In the thin film transistor shown in this embodiment, an active layer is formed using a single crystal or a region that can be regarded as a single crystal. Therefore, there is substantially no crystal grain boundary in the active layer. The configuration can be made unaffected.
[0058]
The structure shown in this embodiment can be effectively used when forming a plurality of thin film transistors arranged in a row. For example, it can be used when a large number of thin film transistors illustrated in FIG. 11D are simultaneously manufactured in a line in the depth direction of the drawing. Such a structure 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. Such a thin film transistor using a crystalline silicon film that can be regarded as a single crystal or 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 (good crystallinity) can be efficiently obtained by skillfully utilizing the mechanism of crystallization by laser light irradiation.
[0060]
FIG. 10 shows a manufacturing process of this example. First, a base silicon oxide film 602 is formed to a thickness of 3000 mm on a glass substrate 601 by sputtering. Then, an amorphous silicon film 603 is formed to a thickness of 500 mm by plasma CVD or low pressure thermal CVD. Next, a mask is formed with a silicon oxide film. As this silicon oxide film, a film formed by sputtering or plasma CVD may be used, but it may be formed by using a coating liquid for forming a silicon oxide film. This is a type in which a solution is solidified by heating at about 100 to 300 ° C. For example, an OCD (Ohka Diffusion Source) solution from 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 the region indicated by 802, and the surface of the amorphous silicon film 603 is exposed in the slit-shaped region 802. This slit-shaped region may be provided with a required length and a width of several μ to several tens of μ (FIG. 10A).
[0061]
Then, as shown in FIG. 10B, irradiation is performed while moving (sweeping) linear laser light in the direction indicated by 811. This linear laser beam is shaped using the optical system shown in FIG. 5 into a shape having a longitudinal direction in the depth direction of the drawing.
[0062]
The irradiation with the laser beam 810 is performed by heating the sample to 500 ° C. and moving the sample at a very slow 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 formation of crystal nuclei and the formation of crystallized regions are due to the action of nickel elements. The laser light irradiation process is the same as that in the third embodiment.
[0063]
When the linear laser beam is irradiated while being moved as indicated by 811, the region indicated by 812 is rapidly cooled after the laser beam irradiation because the silicon oxide film does not exist on the surface thereof. The previous amorphous silicon film to which the laser light has moved is sandwiched between the upper and lower silicon oxide films, so that there is no escape of heat and 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 due to high heat. Naturally, a sudden 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 sequentially proceeds as indicated by 813. Then, a region 814 that can be regarded as a single crystal or a single crystal can be obtained.
[0064]
The structure as shown in this embodiment can realize the easiness of the start of growth at the growth start point, and can form a single crystal or a region that can be regarded as a single crystal although it is partially.
[0065]
Thus, a single crystal or a region that 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
An example of constructing a more advanced active matrix type liquid crystal display system using the invention disclosed in this specification is shown in FIG. The example of FIG. 11 is reduced in size by fixing a semiconductor chip attached to a main board of a normal computer 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. This is an example of reducing the weight and thickness.
[0067]
Hereinafter, FIG. 11 will be described. The substrate 15 is also a substrate for a liquid crystal display, on which an active matrix circuit 14 in which a large number of pixels each having a TFT 11, a pixel electrode 12, and an auxiliary capacitor 13 are formed, and an X decoder / driver for driving it, Y A decoder / driver and an XY branch circuit are formed by TFTs. Needless to say, the invention disclosed in this specification can be used as a TFT.
[0068]
Then, another chip is attached on the substrate 15. These chips are connected to a circuit on the substrate 15 by means such as a wire bonding method or a COG (chip on glass) method. In FIG. 11, a correction memory, a memory, a CPU, and an input port are chips attached in this way, and various other chips may be attached.
[0069]
In FIG. 11, an input port is a circuit that reads an externally input signal and converts it into an image signal. The correction memory is a memory unique to the 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 specific to each pixel as a non-volatile memory, and is used for individual correction. That is, if a pixel of the electro-optical device has a point defect, a signal corrected accordingly is sent to the pixels around the point to cover the point defect and make the defect inconspicuous. Alternatively, when the pixel is darker than the surrounding pixels, a larger signal is sent to the pixel so that the brightness is the same as that of the surrounding pixels. Since the pixel defect information varies from panel to panel, the information stored in the correction memory varies from panel to panel.
[0070]
The CPU and the memory have the same functions as those of a normal computer. In particular, the memory has an image memory corresponding to each pixel as a RAM. These chips are all of the CMOS type.
[0071]
Further, at least a part of the required integrated circuit may be constituted by the invention disclosed in this specification to further increase the thin film of the system.
As described above, even a CPU and a memory are formed on a liquid crystal display substrate, and configuring a simple electronic device such as a personal computer with a single substrate reduces the size of the liquid crystal display system and widens its application range. Is very useful for.
[0072]
A thin film transistor using the invention disclosed in this specification can be used for the circuit shown 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 that can be regarded as a single crystal for an analog buffer or other circuits.
[0073]
【The invention's effect】
In a state where the sample is heated to a temperature within ± 100 ° C. of the temperature at the time of the previous heat treatment with respect to the crystalline silicon film crystallized by introduction of a metal element for promoting crystallization and heat treatment, By performing annealing by irradiation, the crystallinity can be further improved and a silicon film having good crystallinity can be obtained.
[0074]
Also, impurity ions are implanted into the crystalline silicon film crystallized by introduction of a metal element that promotes crystallization and heat treatment, and the temperature is within ± 100 ° C. of the temperature during the previous heat treatment. Impurity regions can be formed effectively by annealing with laser light irradiation while the sample is heated.
[0075]
In addition, by irradiating linear laser light from one side of the amorphous silicon film to the other while being heated to a temperature of 450 ° C. or higher, crystal growth can be performed sequentially according to the laser light irradiation. A region that can be regarded as a single crystal or a single crystal can be formed.
[0076]
In particular, a region with higher crystallinity (a region that can be regarded as a single crystal) can be easily formed by irradiating laser light as described above with a metal element that promotes crystallization introduced into an amorphous silicon film. can do. At this time, irradiation is performed while moving linear laser light, whereby the metal element can be segregated at the end point of crystal growth, and the metal element concentration 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 cross-sectional view of a laser processing apparatus.
FIG. 3 is a cross-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 a laser processing apparatus.
FIG. 6 is a process diagram for manufacturing a crystalline silicon film over a substrate.
7 is a manufacturing process diagram of a thin film transistor. FIG.
FIG. 8 is a process diagram for manufacturing a crystalline silicon film over a substrate.
FIG. 9 is a manufacturing process diagram of a thin film transistor.
FIG. 10 is a process diagram for manufacturing a crystalline silicon film over a substrate.
FIG. 11 is a diagram showing an outline of 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 region
706 Offset gate area
707 Channel formation region
708 Offset gate area
709 drain region
710 Interlayer insulation film
711 Source electrode
712 Drain electrode
802 Exposed area
803 Crystal growth direction
801 resist mask
810 linear laser beam
811 Moving direction of laser beam on line
812 Crystal nucleus or crystalline region
814 Single crystal or a region that can be regarded as a single crystal
815 Mask composed of silicon oxide film

Claims (3)

Holding the linear laser beam in the longitudinal direction perpendicular to the direction of the linear laser beam, by irradiating while moving at a moving speed of 1Mm～10cm / min, amorphous metal element for promoting crystallization is introduced A method for manufacturing a semiconductor device for crystallizing a porous semiconductor film ,
The method for manufacturing a semiconductor device, wherein the irradiation with the linear laser light is performed in a state where the amorphous semiconductor film is heated at a temperature of 450 ° C. to 650 ° C. Holding the linear laser beam in the longitudinal direction perpendicular to the direction of the linear laser beam, by irradiating while moving at a moving speed of 1Mm～10cm / min, amorphous metal element for promoting crystallization is introduced A method for manufacturing a semiconductor device for crystallizing a porous semiconductor film ,
Transfer the substrate from the loading / unloading chamber to the transfer chamber,
Transferring the substrate from the transfer chamber to the heating chamber;
After heating the substrate in the heating chamber, the substrate is transferred to the transfer chamber,
Transferring the substrate from the transfer chamber to the laser irradiation chamber;
The amorphous semiconductor film is irradiated with the linear laser light while heating the substrate at a temperature of 450 ° C. to 650 ° C. in the laser irradiation chamber, and then the substrate is transferred to the transfer chamber,
Transferring the substrate from the transfer chamber to the loading / unloading chamber;
A method for manufacturing a semiconductor device, wherein each of the chambers being transferred is in a high vacuum state. Holding the linear laser beam in the longitudinal direction perpendicular to the direction of the linear laser beam, by irradiating while moving at a moving speed of 1Mm～10cm / min, amorphous metal element for promoting crystallization is introduced A method for manufacturing a semiconductor device for crystallizing a porous semiconductor film ,
Transfer the substrate from the loading / unloading chamber to the transfer chamber,
Transferring the substrate from the transfer chamber to the heating chamber;
After heating the substrate in the heating chamber, the substrate is transferred to the transfer chamber,
Transferring the substrate from the transfer chamber to the laser irradiation chamber;
The amorphous semiconductor film is irradiated with the linear laser light while heating the substrate at a temperature of 450 ° C. to 650 ° C. in the laser irradiation chamber, and then the substrate is transferred to the transfer chamber,
Transferring the substrate from the transfer chamber to the loading / unloading chamber;
All chambers in said transfer is in a high vacuum state, and, by repeating the transfer, irradiated with the linear laser beam on a plurality of substrates, the method of conveying the transfer, the heating chamber and the laser A method for manufacturing a semiconductor device, characterized in that the temperature of the substrate in the irradiation chamber and the time during which one substrate is held in the heating chamber are the same for all the substrates.

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