JP4354165B2 - Laser irradiation apparatus and laser irradiation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of annealing (including crystallization and activation) of a semiconductor film using a laser beam and a laser irradiation apparatus for performing the method (processing a laser and a laser beam output from the laser). Device including an optical system for guiding to the body). The present invention also relates to a method for manufacturing a thin film transistor using a laser irradiation apparatus, a thin film transistor, and a liquid crystal including the thin film transistor. apparatus, The present invention relates to an EL display device and other display devices.
[0002]
[Prior art]
In recent years, a display device having a thin film transistor has been studied, and the display has been increased in size. Along with this, the area of the mother glass has been increased, and crystallization and activation (hereinafter referred to as laser annealing) with a laser beam have been performed on a semiconductor film formed on a large substrate. Laser annealing is a method suitable for mass production because it can be processed in a shorter time than a heating furnace.
[0003]
When performing laser annealing, it is necessary to make the substrate state smooth (flat) in order to prevent non-uniformity of the laser irradiation intensity in the irradiated object (specifically, the substrate surface). was there. However, an actual substrate, particularly an inexpensive glass substrate, has poor smoothness and has a non-uniform laser irradiation intensity.
[0004]
For this reason, in the conventional laser irradiation technique, the irradiated object is attracted to the stage of the laser irradiation apparatus and is irradiated in a smooth state (see, for example, Patent Document 1). In addition, laser irradiation is performed in a state where the substrate is intentionally deformed using a pressure difference in the processing chamber to prevent nonuniformity in laser irradiation intensity (see, for example, Patent Document 2).
[0005]
[Patent Document 1]
JP-A-9-63984
[Patent Document 2]
JP-A-9-63985
[0006]
[Problems to be solved by the invention]
However, in reality, when the optical system of the laser irradiation device cannot ignore the aberration in the direction perpendicular to the irradiated object (specifically, the substrate) (the rays passing through the lens etc. do not gather correctly at one point and an incomplete image can be formed) Inhomogeneity of the laser irradiation intensity occurs within the surface of the irradiated object, making it difficult to perform uniform laser irradiation processing. Kak It was. In addition, since the aberration varies depending on the arrangement of the lens and the characteristics of the lens, it has to be considered in each optical system.
[0007]
Due to the non-uniformity of the laser irradiation intensity, the electrical characteristics of thin film transistors (hereinafter simply referred to as TFTs), which are objects to be irradiated, vary. The variation in TFT has become a problem in the pixel portion and the drive circuit portion of the display device, and has caused display unevenness and streaks on the display screen.
[0008]
Therefore, an object of the present invention is to provide a laser irradiation apparatus and method for reducing the aberration of an optical system. It is another object of the present invention to provide a TFT manufactured by a laser irradiation apparatus with reduced aberrations, an EL display device including the TFT, a liquid crystal display device and other display devices, particularly an active matrix display device. To do.
[0009]
[Means for Solving the Problems]
In view of the above-described problems, the present invention deforms a table (hereinafter referred to as an installation table) on which an object to be irradiated (also referred to as an object to be irradiated) according to the aberration of the optical system, and adsorbs the substrate to the table. It is characterized in that the aberration of the optical system is corrected on the substrate side. Further, the installation base may be disposed on a stage provided in the laser irradiation apparatus, or the stage itself may be deformed according to the aberration.
[0010]
The specific object to be irradiated is a semiconductor film formed on the substrate, but the semiconductor film is often very thin relative to the substrate, and its thickness can be ignored. To do.
[0011]
First, the present invention obtains the relationship between the substrate and the focal position. Based on the obtained result, an installation table is formed, and the substrate is fixed thereon. Thereafter, laser annealing typified by crystallization and activation of the semiconductor film is performed. The installation base may be formed from a metal plate, a plastic plate, or the like, and a mold formed based on the aberration. In addition, the installation base is made so that holes are provided at a plurality of locations, and the installation base having a complicated shape and the substrate are sucked and brought into close contact (the installation base having a suction means is called an adsorption plate), and the entire surface of the substrate is placed. Irradiate with laser light. At this time, the substrate and the laser are relatively moved so that the entire surface of the substrate is irradiated with the laser, and the laser scanning speed with respect to the substrate is set to 10 to 100 cm / s.
[0012]
Since aberration differs depending on the type and arrangement of lenses, it is desirable to measure each optical system and form a suction plate or the like.
[0013]
The optical system has at least a laser and a means for deflecting the laser. Further, it preferably has a convex lens through which the deflected laser passes so that the focal point of the laser beam is substantially within the substrate surface. The specific means for deflecting the laser is either a galvanometer mirror or a polygon mirror, and the specific convex lens is an fθ lens.
[0014]
Further, the present invention is characterized by correcting the aberration of the optical system by performing laser irradiation while raising and lowering the substrate with respect to the obtained aberration. Specifically, the substrate may be vibrated up and down within a frequency range of 0.2 to 20 Hz by means for applying vibration provided on the stage. At this time, the substrate and the laser are relatively moved so that the entire surface of the substrate is irradiated with the laser, and the laser scanning speed with respect to the substrate is set to 10 to 100 cm / s.
[0015]
As described above, according to the present invention, the unevenness of the laser irradiation intensity can be reduced by correcting the aberration of the optical system on the substrate side. The TFT formed in this manner has no unevenness in laser irradiation, and variation in the electrical characteristics of the TFT can be reduced.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. Note that in all the drawings for describing the embodiments, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.
[0017]
(Embodiment 1)
In this embodiment, a method for obtaining aberration will be described with reference to FIGS. Note that the measurement was performed using an optical system having a laser, a galvanometer mirror, and an fθ lens.
[0018]
First, a continuous wave laser light source is processed (deformed) to form a laser beam 601 having a beam length of about 400 μm and a beam width of about 20 μm. Then, the processed laser light is incident on a galvanometer mirror 602 as shown in FIG. 6, and the angle of the galvanometer mirror is changed to reciprocate the surface of the substrate (for example, a 5-inch substrate) 604 in the direction indicated by the arrow 605. Further, the entire surface of the substrate is irradiated with laser by moving the substrate (hereinafter referred to as scanning). At this time, since the distance from the galvanometer mirror is different between the central portion of the substrate and the end portion of the substrate, the fθ lens 603 is used to perform correction so that the focal point of the laser light is substantially within the substrate surface.
[0019]
When the surface of the substrate is observed after scanning, it can be seen that a bright and dark concentric pattern as shown in FIG. 7, that is, concentric unevenness occurs. This dark portion is a portion where crystallization is good, that is, a portion where the focal position is substantially in alignment.
[0020]
Then, the height of the substrate when the laser beam is irradiated is changed, that is, the substrate is moved up and down, and the substrate is scanned in the same manner as in FIG. 7 to obtain the observation data of FIGS. The height of each substrate is 5/6 mm in (a), 6/6 mm in (b), and 7/6 mm in (c).
[0021]
Assuming that the focus of the optical system exists in the dark part, the focus position at an arbitrary position of the substrate is obtained based on the above data. FIG. 8A is a result of plotting the relationship between the position from the center of the substrate and the focal position in the first direction (X-axis direction) and approximating with a quartic function for convenience. The approximation may be performed as appropriate. It can be seen that the aberration of the optical system shown in FIG. 8A is not monotonous but complicated. Similarly, the aberration in the second direction (Y-axis direction) perpendicular to the first direction is obtained.
[0022]
When the aberration as shown in FIG. 8A occurs, the aberration may be corrected on the substrate side so that the substrate surface matches the focal position.
[0023]
As means for correcting the aberration, the substrate may be deformed according to the aberration. Various methods can be considered as means for deforming the substrate. For example, an installation table (suction plate) as shown in FIG. 8B may be designed according to the aberration, and the substrate may be deformed by suction. . This suction plate is formed using a mold having a shape based on the result of FIG. 8A, and holes and grooves for suction (hereinafter referred to as openings) as shown in FIGS. 8C and 8D. ) May be provided at a plurality of locations. Further, as shown in FIG. 8D, it is preferable to provide a large number of openings at locations where the substrate is sucked downward. Of course, the stage on which the substrate is placed may be designed according to the aberration, and may be placed so that the substrate is deformed. In particular, the deformation of the substrate is effective for a substrate that can be freely deformed, such as plastic.
[0024]
Thus, when scanning is performed with the substrate fixed to the suction plate, the scan speed is preferably about 10 to 100 cm / s.
[0025]
As another example of means for correcting aberrations, the substrate may be moved up and down based on the result of FIG. For example, a means for vertically vibrating (a means for moving the stage up and down) is provided on the stage on which the substrate is arranged, and the substrate may be moved up and down at a frequency of 0.2 to 20 Hz in accordance with the aberration.
[0026]
Thus, when scanning is performed while vibrating the substrate up and down, the scan speed is preferably about 10 to 100 cm / s.
[0027]
As described above, uniform laser irradiation can be performed by correcting aberrations in the optical system on the substrate side. Then, it is possible to reduce variations in TFTs manufactured by a laser irradiation method in which aberrations are corrected.
[0028]
(Embodiment 2)
In this embodiment, an example in which laser irradiation is performed with a substrate fixed to an adsorption plate will be described with reference to FIG.
[0029]
As shown in FIG. 1A, the laser irradiation apparatus includes a laser light source 100, a galvano mirror or polygon mirror 101, and a stage 105. In this embodiment, the fθ lens 102 is installed between the substrate and the galvanometer mirror or polygon mirror. Then, as in the first embodiment, the aberration in the optical system of FIG. 1 is obtained, the suction plate 106 is formed, and the substrate 104 is fixed. Next, in a state where the substrate 104 fixed to the suction plate 106 is placed on the stage 105, the laser beam processed into a linear shape is irradiated.
[0030]
Further, the laser irradiation apparatus of the present invention may control the processing atmosphere as shown in FIG. For example, at least a stage, an adsorption plate, and a substrate are arranged in a reaction chamber 201 controlled to be in a reduced pressure state, a nitrogen atmosphere state, or an oxygen atmosphere state, and laser light is irradiated through a window 202 provided in the reaction chamber. do it. In this case, the mirror 203 and the like may be provided either outside the reaction chamber or inside the reaction chamber. Furthermore, laser irradiation may be performed while blowing oxygen from the substrate to the surface (irradiation surface) of the irradiated object. By controlling the laser irradiation atmosphere in this manner, the flatness of the semiconductor film provided on the substrate can be improved.
[0031]
Further, as a scanning method of the present invention, as shown in FIG. 2A, the laser beam is sequentially scanned in a first direction and a second direction (X-axis and Y-axis direction) 201 perpendicular to the first direction. Even when scanning is performed, the entire surface of the substrate may be scanned by scanning the substrate in the second direction 203 while scanning the laser beam in the first direction 202 as shown in FIG.
[0032]
At this time, the shape 103 on the laser light irradiation surface is a rectangle or an ellipse having a large aspect ratio. In the present invention, a laser beam having an aspect ratio of 2 or more (preferably 10 to 100) and having a rectangular shape on the irradiation surface is also included. The reason why the laser beam is linear is to secure an energy density for sufficient annealing of the irradiated surface on the irradiated surface. Therefore, as long as sufficient annealing can be performed on the irradiated object, the shape of the laser beam is not limited, even if it is rectangular or elliptical.
[0033]
At this time, it is preferable to scan so that the laser beams of the pulse laser and the continuous wave laser have the overlap region 109. Further, laser irradiation may be performed by reciprocating scanning a certain area a plurality of times. When a pulse laser is used, the overlap ratio between the irradiation area of one shot and the irradiation area of the next shot is preferably 50 to 98%. Further, a plurality of pulse lasers may be irradiated to the area of one shot. By controlling the number of laser irradiations and the overlap rate in this way, the flatness of the semiconductor film provided on the substrate can be improved.
[0034]
As described above, according to the present invention, the unevenness of the laser irradiation intensity can be reduced by correcting the aberration of the optical system on the substrate side.
[0035]
(Embodiment 3)
In this embodiment, an example in which laser irradiation is performed while moving an object to be irradiated in the vertical direction will be described with reference to FIGS.
[0036]
Similar to FIG. 1, the laser irradiation apparatus shown in FIG. 3 includes a laser light source 100, a galvanometer mirror or polygon mirror 101, a stage 105, and means 20 for moving the stage up and down. 0 is Is provided. In this embodiment, the fθ lens 102 is installed between the substrate and the galvanometer mirror or polygon mirror. Then, as in the first embodiment, the aberration in the optical system of FIG. 3 is obtained, and the means for moving the stage up and down is controlled based on the aberration. Thereafter, the substrate is irradiated with a laser beam processed into a linear shape by a scanning method as shown in FIG.
[0037]
Further, the laser irradiation apparatus of the present invention may control the processing atmosphere as shown in FIG. For example, at least a stage, an adsorption plate, and a substrate are arranged in a reaction chamber 201 controlled to be in a reduced pressure state, a nitrogen atmosphere state, or an oxygen atmosphere state, and laser light is irradiated through a window 202 provided in the reaction chamber. do it. In this case, the mirror 203 and the like may be provided either outside the reaction chamber or inside the reaction chamber. Furthermore, laser irradiation may be performed while blowing oxygen from the vicinity of the substrate to the irradiation surface. By controlling the laser irradiation atmosphere in this manner, the flatness of the semiconductor film provided on the substrate can be improved.
[0038]
As described above, according to the present invention, the unevenness of the laser irradiation intensity can be reduced by correcting the aberration of the optical system on the substrate side.
[0039]
(Embodiment 4)
In this embodiment, a method for manufacturing a TFT formed over an insulating surface will be described with reference to FIGS. Although a plurality of TFTs are provided on the insulating surface, a case where a driver circuit portion having an n-channel TFT and a p-channel TFT and a pixel portion having an n-channel TFT are described.
[0040]
First, as illustrated in FIG. 4A, a base insulating film 402 including a stack of insulating films such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed over a substrate 401 having an insulating surface. Although a two-layer structure is used here as the base insulating film (base film) 402, 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 402a of the base insulating film, a plasma CVD method is used, and SiH _Four , NH _Three , N ₂ O and H ₂ A silicon oxynitride film is formed with a reactive gas of 10 to 200 nm (preferably 50 to 100 nm). Here, a silicon oxynitride film with a thickness of 50 nm is formed. Next, as the second layer 402b of the base insulating film, a plasma CVD method is used, and SiH _Four And N ₂ A silicon oxynitride film formed using O as a reaction gas is stacked to a thickness of 50 to 200 nm (preferably 100 to 150 nm). Here, a silicon oxynitride film with a thickness of 100 nm is formed.
[0041]
Next, a semiconductor film is formed over the base film 402. As the semiconductor film, a semiconductor film having an amorphous structure is formed by a known means (such as sputtering, LPCVD, or plasma CVD). Note that there is no limitation on the material of the semiconductor film, but the semiconductor film is preferably formed of silicon or a silicon germanium alloy. Thereafter, crystallization treatment (laser crystallization) is performed using the laser irradiation apparatus of the present invention. Further, it is preferable to accelerate the crystallization by irradiating a laser after thermal crystallization using a catalyst such as nickel or by performing crystallization in combination with the thermal crystallization method. Note that in this embodiment mode, laser irradiation is performed in a state where the substrate 401 is sucked onto the suction plate as shown in FIG. Of course, laser irradiation may be performed using the method described in any of Embodiment Modes 1 to 3.
[0042]
The crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is 30 Hz, and the laser energy density is 100 to 400 mJ / cm. ² (Typically 200-300mJ / cm ² ). When a YAG laser is used, the second harmonic is used and the pulse oscillation frequency is 1 to 10 kHz, and the laser energy density is 300 to 600 mJ / cm. ² (Typically 350-500mJ / cm ² ) Then, when the laser beam condensed linearly with a width of 100 to 1000 μm, for example, 400 μm is irradiated over the entire surface of the substrate, the superposition ratio (overlap ratio) of the linear laser light at this time is 50 to 98%. Good.
[0043]
After that, as illustrated in FIG. 4B, the crystallized semiconductor film is patterned into a desired shape, so that an island-shaped semiconductor film 405 is formed. The semiconductor film is formed with a thickness of 25 to 80 nm (preferably 30 to 60 nm). At this time, if necessary, the crystallized semiconductor film 405 may be patterned after adding boron (channel doping). Then, for example, an insulating film 406 functioning as a gate insulating film is formed with a thickness of 40 to 150 nm on the semiconductor film 405 by a thermal oxidation method or a plasma CVD method.
In this embodiment mode, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N = 7%, H = 2%) is formed with a thickness of 115 nm by a plasma CVD method. 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.
[0044]
Next, a first conductive film with a thickness of 20 to 100 nm and a second conductive film with a thickness of 100 to 400 nm are stacked over the gate insulating film 406. In this embodiment, a tantalum nitride film with a thickness of 50 nm and a tungsten film with a thickness of 370 nm are sequentially stacked over the gate insulating film 406. The first conductive film and the second conductive film may be formed using an element selected from Ta, W, Ti, Mo, Al, and Cu, 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, or an AgPdCu alloy may be used as the first conductive film and the second conductive film. Further, the present invention is not limited to the two-layer structure. For example, a three-layer structure in which a 50 nm-thickness tungsten film, a 500 nm-thick aluminum and silicon alloy (Al-Si) film, and a 30 nm-thickness titanium nitride film are sequentially stacked Also good. In the case of a three-layer structure, tungsten nitride may be used instead of tungsten of the first conductive film, or aluminum instead of the aluminum and silicon alloy (Al-Si) film of the second conductive film. A titanium alloy film (Al—Ti) may be used, or a titanium film may be used instead of the titanium nitride film of the third conductive film. Moreover, a single layer structure may be sufficient.
[0045]
After that, patterning is performed in the following procedure to form each gate electrode and each wiring (not shown) in which the first conductive film 407 and the second conductive film 408 shown in FIG. 4C are stacked. First, after forming a resist mask, first etching and second etching are performed. The first etching condition is that the etching gas is CF. _Four And Cl ₂ And O ₂ The gas flow ratio is 25/25/10 sccm, 700 W RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1 Pa, and 150 W RF (13.56) is applied to the substrate side (sample stage). MHz) power is applied and a substantially negative self-bias voltage is applied. Under this etching condition, only the W film is etched so that the end portion is tapered with an angle of 15 to 45 °.
[0046]
Thereafter, the second etching is performed without removing the resist mask. The second etching condition is that the etching gas is CF. _Four And Cl ₂ The gas flow ratio is 30/30 sccm, 500 W of RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1 Pa, and 20 W of RF (13.56 MHz) is also applied to the substrate side (sample stage). ) Apply power and apply a substantially negative self-bias voltage. Under the second etching conditions, both the W film and the TaN film are etched to the same extent, and a gate electrode in which the first conductive film 407 and the second conductive film 408 are stacked is formed.
[0047]
Next, a third etching is performed without removing the resist mask. Here, the third etching condition is that the etching gas is CF. _Four And Cl ₂ The gas flow ratio is 30/30 sccm and 500 W of RF13.56 MHz power is applied to the coil-type electrode at a pressure of 1 Pa, and 20 W of RF13.56 MHz power is also applied to the substrate side (sample stage). Then, a substantially negative self-bias voltage is applied.
[0048]
Thereafter, the fourth etching is performed without removing the resist mask. The fourth etching condition is that the etching gas is CF. _Four And Cl ₂ And O ₂ The gas flow ratio is 20/20/20 sccm, and 500 W of RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1 Pa, and 20 W of RF ( 13.56MHz) Apply power and apply a substantially negative self-bias voltage. The W film and the TaN film are anisotropically etched by the third etching and the fourth etching. Also, by including oxygen in the etching gas, the etching rate of the W film and the TaN film is differentiated, and the etching rate of the W film is made faster than the etching rate of the TaN film. Although not shown, the gate insulating film not covered with the first conductive layer is etched and thinned. At this stage, as shown in FIG. 4D, a gate electrode and wiring (not shown) having the first conductive layer (TaN film) 407 ′ as a lower layer and the second conductive layer (W film) 408 ′ as an upper layer. ) Is formed.
[0049]
Next, without removing the resist mask, a first doping process is performed in which an impurity element imparting conductivity is added to the semiconductor film using the gate electrode as a mask. The first doping process may be performed by an ion doping method or an ion implantation method. Typically, phosphorus (P) or arsenic (As) is used as the impurity element imparting n-type conductivity. A first impurity region 410 is formed in a self-aligning manner. The first impurity region has 1 × 10 ²⁰ ~ 1x10 ^{twenty one} /cm ^Three An impurity element imparting n-type is added in a concentration range of.
[0050]
Next, as shown in FIG. 4E, a mask 412 made of a new resist is provided on part of the p-channel TFT and the n-channel TFT in the pixel portion, and a second doping process is performed. The second doping process may be performed by an ion doping method or an ion implantation method. In this embodiment, an ion doping method is used, and phosphine (PH _Three Gas) diluted to 5% with hydrogen at a flow rate of 30 sccm and a dose of 1.5 × 10 ¹⁴ atoms / cm ² And the acceleration voltage is 90 keV. A mask made of resist and the first conductive layer serve as a mask, and a second impurity region 411 overlapping with the gate electrode is formed by the second doping process. The second impurity region 411 has 1 × 10 ¹⁶ ~ 1x10 ¹⁷ /cm ^Three An impurity element imparting n-type is added in a concentration range of.
[0051]
Next, as shown in FIG. 5H, after removing the resist mask, a new resist mask 413 is formed and a third doping process is performed. By the third doping treatment, an impurity region in which an impurity element imparting p-type conductivity (boron or the like) is added to the semiconductor layer forming the semiconductor layer for forming the p-channel TFT is formed. Similarly to the n-channel TFT, a third impurity region that overlaps with the gate electrode and a fourth impurity region that does not overlap with the gate electrode are formed. Although the impurity region is a region to which phosphorus (P) is added in the previous step, the conductivity type is p-type because the concentration of the impurity element imparting p-type is added 1.5 to 3 times its concentration. It has become.
[0052]
Through the above steps, impurity regions having n-type or p-type conductivity are formed in each semiconductor layer.
[0053]
After the impurity region is formed, the impurity element is activated using a heating furnace or laser light. In the present embodiment, FIG. Figure Laser activation is performed using the laser irradiation apparatus shown in FIG. In particular, it may be activated by irradiating the second harmonic of a YAG laser, and the YAG laser is a preferred activation means because it requires less maintenance. Note that heat treatment or strong light irradiation may be performed instead of activation by laser irradiation, and these activation means may be used in combination. For example, it is preferable to activate the impurity element using an excimer laser from the front surface or the back surface in an atmosphere of room temperature to 300 ° C. At this time, plasma damage to the gate insulating film and plasma damage to the interface between the gate insulating film and the semiconductor layer can be recovered simultaneously with activation.
[0054]
Next, as shown in FIG. 5G, a first passivation film 414 made of an insulating film such as a silicon oxynitride film or silicon oxide is formed. In this embodiment, a silicon oxynitride film is formed to a thickness of 100 nm by a plasma CVD method. Then, using a clean oven, the semiconductor film is hydrogenated by heating at 300 to 550 ° C. for 1 to 12 hours. In this embodiment mode, heating is performed at 410 ° C. for 1 hour in a nitrogen atmosphere. In this step, dangling bonds in the semiconductor layer can be terminated by hydrogen contained in the first passivation film 414. In addition, the activation treatment of the impurity regions can be performed simultaneously with hydrogenation.
[0055]
After that, as shown in FIG. 5H, an interlayer insulating film 415 made of an organic insulating material is formed over the first passivation film 414. As the organic insulating material, a positive photosensitive organic resin or a negative photosensitive organic resin can be used. In this embodiment mode, a photosensitive acrylic resin film having a thickness of 1.05 μm is formed as the interlayer insulating film. After that, a second passivation film 416 made of a nitride insulating film (typically a silicon nitride film or a silicon nitride oxide film) is formed over the interlayer insulating film 415. In this embodiment, a silicon nitride film is used for the second passivation film 416. As film formation conditions, a silicon target may be used by sputtering using high frequency discharge, and nitrogen gas may be used as a sputtering gas. The pressure may be set as appropriate, but may be 0.5 to 1.0 Pa, the discharge power is 2.5 to 3.5 kW, and the film formation temperature is within the range of room temperature (25 ° C.) to 250 ° C. By forming the second passivation film made of the nitride insulating film in this way, degassing generated from the first interlayer insulating film can be suppressed.
[0056]
After that, as shown in FIG. 5I, the interlayer insulating film 415 and the second passivation film 416 are patterned and etched to form a first opening having a curvature (smooth inner wall). Forming an opening having a curvature in this manner has an effect of improving the coverage (coverage) of an electrode to be formed later. The etching process at this time may be a dry etching process or a wet etching process. In the present embodiment, CF _Four And O ₂ And H ₂ The second passivation film 415 and the first interlayer insulating film 414 are etched by dry etching using a mixed gas and an opening is formed. Next, in the same processing equipment, CHF _Three The first passivation film 414 and the gate insulating film 406 are etched by dry etching using a mixed gas of Ar and Ar to form an opening.
[0057]
Next, a metal film is formed in the opening, and the metal film is etched to form a source electrode, a drain electrode, and wirings (not shown). As the metal film, a film made of an element of aluminum (Al), titanium (Ti), molybdenum (Mo), tungsten (W), or silicon (Si) or an alloy film using these elements may be used. In the present embodiment, a titanium film / titanium-aluminum alloy film / titanium film (Ti / Al—Si / Ti) is laminated to 100/350/100 nm, respectively, and then patterned and etched into a desired shape to form a source electrode The drain electrode 416 and each wiring (not shown) are formed.
[0058]
Thereafter, an electrode (which becomes an anode or a cathode in the case of an EL display device and a pixel electrode in the case of a liquid crystal display device) is formed. For the electrode, ITO, SnO ₂ In the case of a reflective liquid crystal display device, a metal film such as Al can be used. Note that in this embodiment mode, the electrode 417 is formed by depositing an ITO film with a thickness of 110 nm and etching it into a desired shape.
[0059]
Through the steps as described above, an active matrix substrate including a TFT with reduced unevenness due to laser irradiation on an insulating surface is completed.
[0060]
The active matrix substrate thus formed can be used for a drive circuit portion or a pixel portion of a liquid crystal display device, an EL display device, or other display devices.
[0061]
(Embodiment 5)
In this embodiment mode, a video camera, a digital camera, a navigation system, a sound reproducing device (car audio system) is provided as an electronic device including a TFT and a light emitting element or a liquid crystal element which are subjected to laser annealing using the laser processing apparatus of the present invention. , Audio components, etc.), notebook personal computers, game machines, portable information terminals (mobile computers, mobile phones, portable game machines, electronic books, etc.), and image playback devices equipped with recording media (specifically, Digital Versatile Discs) (A device provided with a display capable of reproducing a recording medium such as (DVD) and displaying the image). Specific examples of these electronic devices are shown in FIGS.
[0062]
FIG. 9A illustrates a display device, which includes a housing 2001, a support base 2002, a display portion 2003, a speaker portion 2004, a video input terminal 2005, and the like. A light-emitting element or a liquid crystal element including a TFT formed according to the present invention can be used for the display portion 2003. The display device includes all light emitting devices for displaying information such as for personal computers, for receiving TV broadcasts, and for displaying advertisements.
[0063]
FIG. 9B illustrates a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103, operation keys 2104, an external connection port 2105, a shutter 2106, and the like. A light-emitting element or a liquid crystal element including a TFT formed according to the present invention can be used for the display portion 2102.
[0064]
FIG. 9C illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. A light-emitting element or a liquid crystal element including a TFT formed according to the present invention can be used for the display portion 2203.
[0065]
FIG. 9D illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. A light-emitting element or a liquid crystal element including a TFT formed according to the present invention can be used for the display portion 2302.
[0066]
FIG. 9E illustrates a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion A2403, a display portion B2404, and a recording medium (DVD or the like). A reading unit 2405, operation keys 2406, a speaker unit 2407, and the like are included. Although the display portion A 2403 mainly displays image information and the display portion B 2404 mainly displays character information, a light-emitting element or a liquid crystal element including a TFT formed according to the present invention is used for the display portions A, B 2403, and 2404. it can. Note that an image reproducing device provided with a recording medium includes a home game machine and the like.
[0067]
FIG. 9F illustrates a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control receiving portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, and the like. . A light-emitting element or a liquid crystal element including a TFT formed according to the present invention can be used for the display portion 2602.
[0068]
FIG. 9G illustrates a cellular phone, which includes a main body 2701, a housing 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. A light-emitting element or a liquid crystal element including a TFT formed according to the present invention can be used for the display portion 2703. Note that the display portion 2703 can suppress current consumption of the mobile phone by displaying white characters on a black background.
[0069]
As described above, the applicable range of the present invention is so wide that it can be used for electronic devices in various fields.
[0070]
(Embodiment 6)
In the electronic device described in Embodiment 5, a module in which an IC including a controller, a power supply circuit, and the like is mounted on a panel in which a light-emitting element or a liquid crystal element is sealed is mounted. Both the module and the panel correspond to one mode of the display device. In this embodiment, a specific configuration of the module will be described.
[0071]
FIG. 10A shows an external view of a module in which the controller 1001 and the power supply circuit 1002 are mounted on the panel 1000. The panel 1000 includes a pixel portion 1003 in which a light emitting element is provided in each pixel, a scanning line driver circuit 1004 for selecting a pixel included in the pixel portion 1003, and a signal line driver circuit 1005 for supplying a signal to the selected pixel. And are provided.
[0072]
The printed circuit board 1006 is provided with a controller 1001 and a power supply circuit 1002. Various signals and power supply voltages output from the controller 1001 or the power supply circuit 1002 are supplied to the pixel portion 1003 of the panel 1000 and the scanning line driving circuit via the FPC 1007. 1004, supplied to the signal line driver circuit 1005.
[0073]
The power supply voltage and various signals to the printed circuit board 1006 are supplied via an interface (I / F) unit 1008 in which a plurality of input terminals are arranged.
[0074]
Note that in this embodiment mode, the printed circuit board 1006 is mounted on the panel 1000 using an FPC; however, the present invention is not necessarily limited to this structure. The controller 1001 and the power supply circuit 1002 may be directly mounted on the panel 1000 using a COG (Chip on Glass) method.
[0075]
Further, in the printed circuit board 1006, noise may occur in a power supply voltage or a signal, or a signal may be slow to rise due to a capacitance formed between wirings to be drawn or a resistance of the wiring itself. Therefore, various elements such as a capacitor and a buffer may be provided on the printed circuit board 1006 to prevent noise from being applied to the power supply voltage and the signal and the rise of the signal from being slowed down.
[0076]
FIG. 10B is a block diagram illustrating a structure of the printed circuit board 1006. Various signals and power supply voltage supplied to the interface 1008 are supplied to the controller 1001 and the power supply voltage 1002.
[0077]
The controller 1001 includes a phase locked loop (PLL) 1010, a control signal generation unit 1011, and an A / D converter 1009 and SRAMs (Static Random Access Memory) 1012 and 1013 as necessary. Note that the reason for providing as necessary is that the input signal is appropriately provided depending on whether the input signal is an analog signal or a digital signal or the pixel configuration of the panel is controlled by either the analog signal or the digital signal. Instead of SRAM, SDRAM or dynamic random access memory (DRAM) can be used if data can be written or read at high speed.
[0078]
The video signal supplied via the interface 1008 is parallel-serial converted by the A / D converter 1009 and input to the control signal generation unit 1011 as a video signal corresponding to each color of R, G, and B. The A / D converter 1009 generates an Hsync signal, a Vsync signal, a clock signal CLK, and an AC voltage (AC Cont) based on various signals supplied via the interface 1008, and inputs them to the control signal generation unit 1011. Be done
[0079]
The phase locked loop 1010 has a function of matching the frequency of various signals supplied via the interface 1008 with the phase of the operating frequency of the control signal generation unit 1011. The operating frequency of the control signal generator 1011 is not necessarily the same as the frequency of various signals supplied via the interface 1008, but the operating frequency of the control signal generator 811 is adjusted in the phase locked loop 1010 so as to be synchronized with each other. .
[0080]
When the signal input to the control signal generation unit 1011 is a video signal, it is once written and held in the SRAMs 1012, 1013. The control signal generation unit 1011 reads out the video signals corresponding to all the pixels bit by bit from among the video signals of all the bits held in the SRAM 1012, and supplies them to the signal line driver circuit 1005 of the panel 1000.
[0081]
In addition, the control signal generation unit 1011 supplies information regarding a period during which the light emitting element emits light of each bit to the scanning line driving circuit 1004 of the panel 1000.
[0082]
The power supply circuit 1002 supplies a predetermined power supply voltage to the signal line driver circuit 1005, the scan line driver circuit 1004, and the pixel portion 1003 of the panel 1000.
[0083]
Next, a detailed configuration of the power supply circuit 1002 will be described with reference to FIG. The power supply circuit 1002 according to this embodiment includes a switching regulator 1054 using four switching regulator controls 1060 and a series regulator 1055.
[0084]
In general, a switching regulator is smaller and lighter than a series regulator, and can perform step-up and positive / negative inversion as well as step-down. On the other hand, series regulators are used only for step-down, but output voltage accuracy is better than switching regulators, and almost no ripple or noise occurs. The power supply circuit 1002 of this embodiment uses both in combination.
[0085]
A switching regulator 1054 shown in FIG. 11 includes a switching regulator control (SWR) 1060, an attenuator (ATT) 1061, a transformer (T) 1062, an inductor (L) 1063, and a reference power supply (Vref) 1064. An oscillation circuit (OSC) 1065, a diode 1066, a bipolar transistor 1067, a variable resistor 1068, and a capacitor 1069.
[0086]
The switching regulator 1054 converts a voltage of an external Li ion battery (3.6 V) or the like, thereby generating a power supply voltage supplied to the cathode and a power supply voltage supplied to the switching regulator 1054.
[0087]
The series regulator 1055 includes a band gap circuit (BG) 1070, an amplifier 1071, an operational amplifier 1072, a current source 1073, a variable resistor 1074, and a bipolar transistor 1075, and a power supply voltage generated in the switching regulator 1054. Is supplied.
[0088]
The series regulator 1055 uses a power supply voltage generated in the switching regulator 1054 and wiring (current supply line) for supplying current to the anodes of the light emitting elements of the respective colors based on the constant voltage generated in the band gap circuit 1070. To generate a DC power supply voltage.
[0089]
Note that the current source 1073 is used in the case of a driving method in which a current of a video signal is written to a pixel. In this case, the current generated in the current source 1073 is supplied to the signal line driver circuit 1005 of the panel 1000. Note that in the case of a driving method in which a voltage of a video signal is written to a pixel, the current source 1073 is not necessarily provided.
[0090]
Note that the switching regulator, the OSC, the amplifier, and the operational amplifier can be formed using the manufacturing method of the present invention.
[0091]
【The invention's effect】
The present invention can reduce non-uniformity of the laser irradiation intensity by correcting the aberration of the optical system on the substrate side. The TFT formed in this manner has no unevenness in laser irradiation, and variation in the electrical characteristics of the TFT can be reduced.
[Brief description of the drawings]
FIG. 1 shows a laser irradiation method of the present invention.
FIG. 2 is a diagram showing a laser irradiation method of the present invention.
FIG. 3 shows a laser irradiation method of the present invention.
4A and 4B illustrate a method for manufacturing a thin film transistor using a laser irradiation method of the present invention.
FIGS. 5A and 5B illustrate a method for manufacturing a thin film transistor using the laser irradiation method of the present invention. FIGS.
FIG. 6 shows a laser irradiation method of the present invention.
FIG. 7 is a diagram showing the irradiation unevenness obtained by the present invention.
FIG. 8 is a view showing a suction plate of the present invention.
FIG 9 illustrates an electronic device of the present invention.
FIG. 10 illustrates an electronic device of the invention.
FIG. 11 is a diagram showing a power supply circuit of the present invention.

Claims (19)

In a laser irradiation apparatus having a laser, means for deflecting the laser, a convex lens through which the deflected laser passes, and a table on which an object to be irradiated is placed,
Installation surface of said platform, the laser irradiation apparatus, characterized in that it has a shape based on the aberration by means and said convex lens for deflecting the laser obtained by irradiating the laser on the irradiated object. In a laser irradiation apparatus having a laser, any one of a galvano mirror and a polygon mirror, an fθ lens, and a table on which an object to be irradiated is installed,
Installation surface of said platform, the laser irradiation apparatus, characterized in that it comprises any one, as well as shape based on the aberration by the fθ lens of the galvano mirror and the polygon mirror obtained by irradiating the laser on the irradiated object . According to claim 1 or 2, wherein the laser irradiation device irradiated object is characterized in that it is fixed by suction through an opening provided in said platform. In a laser irradiation apparatus having a laser, means for deflecting the laser, a convex lens through which the deflected laser passes, and a table on which an object to be irradiated is placed,
Said platform, said laser irradiation apparatus, wherein the upper and lower make it based on the aberration by means and said convex lens for deflecting the laser obtained by the laser irradiation with the irradiated object. In a laser irradiation apparatus having a laser, any one of a galvano mirror and a polygon mirror, an fθ lens, and a table on which an object to be irradiated is installed,
Said platform, said laser irradiation apparatus, wherein the upper and lower make it based on the aberration by the laser to any one and the fθ lens of the galvano mirror and the polygon mirror obtained by irradiating the object to be irradiated. In any one of claims 1 to 5, the laser irradiation apparatus, characterized in that the irradiated object in a reaction chamber in which the atmosphere is controlled is installed. A laser, an optical system having a projection lens which means and the deflected laser for deflecting the laser passes, in the laser irradiation method using,
Irradiate the irradiated object with the laser, determine the aberration due to the optical system , deform the irradiated object based on the determined aberration,
A laser irradiation method comprising irradiating the deformed irradiated object with the laser. A laser, an optical system having a projection lens which means and the deflected laser for deflecting the laser passes, in the laser irradiation method using,
Irradiate the irradiated object with the laser, determine the aberration by the means for deflecting the laser and the convex lens, deform the irradiated object based on the determined aberration,
A laser irradiation method comprising irradiating the deformed irradiated object with the laser. In a laser irradiation method using a laser and an optical system having any one of a galvano mirror and a polygon mirror and an fθ lens,
Irradiating the laser to be irradiated, the calculated aberration by the galvano mirror and any one and the fθ lens of the polygon mirror, to deform the irradiated object based on the obtained aberration,
A laser irradiation method comprising irradiating the deformed irradiated object with the laser. A laser, an optical system having a projection lens which means and the deflected laser for deflecting the laser passes, in the laser irradiation method using,
Irradiate the irradiated object with the laser, determine aberrations by means for deflecting the laser and the convex lens , and place the irradiated object on a table having a shape based on the determined aberration ;
The laser irradiation method characterized by irradiating the said irradiated object with the said laser. In a laser irradiation method using a laser and an optical system having any one of a galvano mirror and a polygon mirror and an fθ lens,
Irradiating the laser irradiation object, obtains the aberration by the galvano mirror and any one and the fθ lens of the polygon mirror, a base having a shape based on the obtained aberration, established the irradiated object,
The laser irradiation method characterized by irradiating the said irradiated object with the said laser. 12. The laser irradiation method according to claim 10, wherein the object to be irradiated is sucked and fixed through an opening provided in the table. A laser, an optical system having a projection lens which means and the deflected laser for deflecting the laser passes, in the laser irradiation method using,
Irradiating the laser irradiation object, it obtains the aberration due the optical system, the table to be moved up or down based on the previous SL obtained aberration, established the irradiated object,
A laser irradiation method comprising irradiating the irradiated object with the laser while moving the table up and down . A laser, an optical system having a projection lens which means and the deflected laser for deflecting the laser passes, in the laser irradiation method using,
Irradiating the laser irradiation object, obtains the aberration by means and said convex lens for deflecting the laser, the pedestal to move up or down based on the previous SL obtained aberration, established the irradiated object,
A laser irradiation method comprising irradiating the irradiated object with the laser while moving the table up and down . In a laser irradiation method using a laser and an optical system having any one of a galvano mirror and a polygon mirror and an fθ lens,
Irradiating the laser to be irradiated, the calculated aberration by the galvano mirror and any one and the fθ lens of the polygon mirror, the object to be irradiated is placed on a table that moves up or down based on the obtained aberration ,
A laser irradiation method comprising irradiating the irradiated object with the laser while moving the table up and down . The laser irradiation method according to claim 13 , wherein the stage is moved up and down at a frequency of 0.2 to 20 Hz. In any one of claims 7 to 16, a laser irradiation method is characterized in that to scan the laser in a second direction perpendicular to the first direction and the first direction. In any one of claims 7 to 16, laser irradiation, characterized in that moving the laser is scanned in a first direction, and the irradiated object in a second direction perpendicular to said first direction Method. In any one of claims 7 to 18, a laser irradiation method, wherein the object to be irradiated is a semiconductor film formed on a substrate.

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