JP4731655B2 - Method for manufacturing semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device having a circuit composed of thin film transistors (hereinafter referred to as TFTs). For example, the present invention relates to an electro-optical device typified by a liquid crystal display panel and a configuration of an electronic apparatus in which such an electro-optical device is mounted as a component.
[0002]
Note that in this specification, a semiconductor device refers to all devices that can function by utilizing semiconductor characteristics, and an electro-optical device, a semiconductor circuit, and an electronic device are all semiconductor devices.
[0003]
[Prior art]
In recent years, a technique for forming a thin film transistor (TFT) using a semiconductor thin film (having a thickness of about several to several hundred nm) formed on a substrate having an insulating surface has attracted attention. Thin film transistors are widely applied to electronic devices such as ICs and electro-optical devices, and development of switching devices for image display devices is urgently required.
[0004]
For example, in a liquid crystal display device, a pixel unit that individually controls pixels arranged in a matrix, a driver circuit that controls the pixel unit, and a logic circuit (such as a processor circuit or a memory circuit) that processes an external data signal Attempts have been made to apply TFTs to all electrical circuits.
[0005]
A configuration (system on panel) in which these circuits (pixel portion, driver circuit, etc.) are integrated on a single substrate is known. In the pixel portion, the pixel plays a role of holding information sent from the driver circuit, and if the off-state current of the TFT connected to the pixel is not sufficiently small, the information cannot be held, which is good. You cannot get a display.
[0006]
On the other hand, in a driver circuit, TFTs are required to have high mobility, and the higher the mobility, the simpler the circuit structure and the faster the display device can be operated.
[0007]
As described above, the required characteristics are different between the TFT arranged in the driver circuit and the TFT arranged in the pixel portion. That is, TFTs arranged in the pixel portion are not required to have a high mobility, but are required to have a small off-current and a uniform value in the pixel portion. On the other hand, the mobility of the TFT of the driver circuit arranged in the periphery is given priority over the off current, and high mobility is required.
[0008]
However, it has been difficult to manufacture a TFT that prioritizes mobility and a TFT with a small off-current with high productivity without impairing reliability by using a conventional manufacturing method.
[0009]
[Problems to be solved by the invention]
As described above, in order to realize a system-on-panel with a built-in logic circuit, a completely new configuration that is not conventionally required is required.
[0010]
The present invention answers such a requirement, and each circuit of an electro-optical device typified by AM-LCD is formed with a TFT having an appropriate structure according to the function, and has high reliability. It is an issue to provide.
[0011]
[Means for Solving the Problems]
The configuration of the invention disclosed in this specification is as follows.
In a semiconductor device having a driver circuit and a pixel portion formed over the same substrate,
The channel formation region of at least one TFT included in the driver circuit is a crystalline semiconductor film,
In the semiconductor device, the channel formation region of the TFT included in the pixel portion is formed of an amorphous semiconductor film.
[0012]
In the above structure, a channel formation region of at least one TFT included in the driver circuit is formed through an irradiation process using a laser or strong light similar to the laser.
[0013]
In the above structure, the channel formation region of at least one TFT included in the driver circuit and the TFT included in the pixel portion is formed of a semiconductor film formed by a sputtering method.
[0014]
In the above structure, the gate insulating film of at least one TFT included in the driver circuit and the TFT included in the pixel portion is formed of an insulating film formed by a sputtering method.
[0015]
In the above structure, the crystalline semiconductor film is polysilicon, and the amorphous semiconductor film is amorphous silicon.
[0016]
In each of the above structures, the semiconductor device is an active matrix display device, for example, an EL display device or a liquid crystal display device.
[0017]
The configuration of the invention for realizing the above structure is as follows.
A method for manufacturing a semiconductor device having a driver circuit and a pixel portion over the same substrate,
A first step of forming an amorphous semiconductor film on the insulating surface;
A second step of selectively irradiating the amorphous semiconductor film with a laser or strong light similar thereto to make a part of the amorphous semiconductor film a crystalline semiconductor film;
Patterning the crystalline semiconductor film to form a semiconductor layer of a driver circuit; patterning the amorphous semiconductor film to form a semiconductor layer of a pixel portion; and
A fourth step of forming an insulating film on the semiconductor layer;
A fifth step of forming a gate electrode on the insulating film;
A method for manufacturing a semiconductor device.
[0018]
In the above structure, the fourth step is performed by a sputtering method.
[0019]
In addition, the configuration of other inventions is as follows:
A method for manufacturing a semiconductor device having a driver circuit and a pixel portion over the same substrate,
A first step of forming an amorphous semiconductor film on the insulating surface;
A second step of forming an insulating film on the amorphous semiconductor film;
A third step of selectively irradiating the amorphous semiconductor film with a laser or intense light similar to the amorphous semiconductor film through the insulating film to make a part of the amorphous semiconductor film a crystalline semiconductor film;
Patterning the crystalline semiconductor film to form a semiconductor layer of a driver circuit; patterning the amorphous semiconductor film to form a semiconductor layer of a pixel portion; and
A fifth step of forming a gate electrode on the insulating film;
A method for manufacturing a semiconductor device.
[0020]
In the above structure related to the manufacturing method, the second step is performed by a sputtering method.
[0021]
In each of the above structures related to the manufacturing method, the first step is performed by a sputtering method.
[0022]
In addition, the configuration of other inventions is as follows:
A method for manufacturing a semiconductor device having a driver circuit and a pixel portion over the same substrate,
A first step of forming a gate electrode on the insulating surface;
A second step of forming an insulating film on the gate electrode;
A third step of forming an amorphous semiconductor film on the insulating film;
A fourth step of selectively irradiating the amorphous semiconductor film with a laser or strong light similar thereto to make a part of the amorphous semiconductor film a crystalline semiconductor film;
Patterning the crystalline semiconductor film to form a semiconductor layer of a driver circuit; patterning the amorphous semiconductor film to form a semiconductor layer of a pixel portion; and
A method for manufacturing a semiconductor device.
[0023]
Moreover, in each said structure regarding a manufacturing method, after the said 5th process,
A sixth step of selectively adding an element belonging to Group 15 or Group 13 to a region to be a source region or a drain region;
A seventh step of activating the elements belonging to Group 13 and Group 15 added to the semiconductor layer;
It is characterized by having.
[0024]
In each of the above structures related to a manufacturing method, the semiconductor device is a liquid crystal display device.
[0025]
Further, in the above configuration relating to the manufacturing method, after the seventh step of performing the activation process,
An eighth step of forming an interlayer insulating film above the active layer;
A ninth step of forming a pixel electrode on the interlayer insulating film;
A tenth step of forming an EL layer on the pixel electrode;
And an eleventh step of forming a cathode or an anode on the EL layer.
[0026]
In each of the above structures related to a manufacturing method, the semiconductor device is an EL display device.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. In the present invention, an amorphous semiconductor film or a crystalline semiconductor film is used as an active layer of a TFT of each circuit of an electro-optical device typified by an AM-LCD or an EL display device formed on the same substrate depending on the function. It is characterized by using. For example, in an electro-optical device typified by an AM-LCD or an EL display device, an amorphous semiconductor film (amorphous silicon film or the like) is used as an active layer of a TFT disposed in a pixel portion, and a driver circuit or a logic circuit is used. Similarly, a crystalline semiconductor film (polysilicon film, polycrystalline silicon film, etc.) is used as an active layer of a TFT disposed in an electric circuit that requires high-speed operation performance.
[0028]
In order to realize the above structure, it is necessary to selectively crystallize an amorphous semiconductor film on the same substrate to form a crystalline semiconductor film, and the present invention is also characterized by its formation method.
[0029]
An example of the forming method of the present invention will be described with reference to FIG. FIG. 1 is a simplified diagram showing an example in which only an amorphous semiconductor film of a driver circuit 103 formed on a substrate is irradiated with a pulsed laser such as an excimer laser.
[0030]
In FIG. 1, reference numeral 101 denotes a substrate having heat resistance, and a glass substrate, a quartz substrate, a silicon substrate, a ceramic substrate, or a metal substrate (typically a stainless steel substrate) may be used. Regardless of which substrate is used, a base film (preferably an insulating film containing silicon as a main component) may be provided as necessary. Note that although not illustrated, an amorphous semiconductor film formed by a sputtering method is provided over the substrate 101. Therefore, although a clear boundary is not actually visible at this stage, the pixel portion 102 and the driver circuit 103 to be formed later are shown for convenience.
[0031]
The laser light emitted from the excimer laser light source 105 is adjusted in beam shape, energy density, and the like by an optical system (a beam homogenizer 106, a mirror 107, etc.) to form a laser spot 108. Then, by moving the XY stage 104 to which the substrate 101 is fixed in the X direction or the Y direction, only the amorphous semiconductor film of the driver circuit 103 is irradiated with the laser spot 108 in the laser spot scanning direction 109. However, taking into consideration the film thickness of the amorphous semiconductor film, etc., the conditions of laser light (irradiation intensity, pulse width, repetition frequency, irradiation time, substrate temperature, stage moving speed, overlap rate, etc.) Will be determined as appropriate. In addition, here, when laser light is leaked and irradiates the pixel portion 102, characteristics of the TFT vary, so it is important to arrange an optical system so that the laser light does not leak. In addition, it is necessary to appropriately set the distance X between the driver circuit and the pixel portion.
[0032]
When the laser irradiation method shown in FIG. 1 is used, only the driver circuit 103 can be irradiated with laser light, and the amorphous silicon film can be selectively crystallized.
[0033]
As the laser light, in addition to a pulsed laser such as an excimer laser, a continuous wave laser such as an argon laser or a continuous light emitting excimer laser can be used.
[0034]
Alternatively, after the insulating film is formed over the amorphous semiconductor film, the laser light irradiation may be performed.
[0035]
FIG. 6 shows an example of irradiation with a continuous wave laser such as an argon laser. In FIG. 6, 601 is a substrate, 606 is a beam expander, 607 is a galvanometer, and 604 is a uniaxial operation stage. Although not shown, an amorphous semiconductor film using a sputtering method is provided over the substrate 601.
[0036]
The laser beam emitted from the argon laser light source 605 is adjusted in beam shape, energy density, and the like by an optical system (a beam expander 606, a galvanometer 607, an f-theta lens 608, etc.) to form a laser spot 609. Then, by vibrating the galvanometer, the laser spot 609 is vibrated in a direction parallel to the laser spot scanning direction 610, and at the same time, the uniaxial operation stage 604 to which the substrate 601 is fixed is moved in one direction (operation direction 611 of the uniaxial operation stage). Only the amorphous semiconductor film of the driver circuit 603 is crystallized by step movement (the step interval is about the spot diameter). Similar to the laser irradiation method shown in FIG. 1, it is important to arrange the optical system so that the laser beam is leaked and the pixel portion 602 is not irradiated.
[0037]
If the laser irradiation method shown in FIG. 6 is used, it is possible to irradiate only the driver circuit with laser light as in the laser irradiation method shown in FIG. 1, and the amorphous silicon film can be selectively crystallized. it can.
[0038]
In addition to the structures in FIGS. 1 and 6, a resist mask using a normal photolithography process may be formed on the substrate so that laser light is leaked and the pixel portion is not irradiated, or a photomask is used. Also good.
[0039]
1 and 6 show an example in which a spot laser is formed, but there is no particular limitation, and a configuration in which linear laser light is selectively irradiated using a mask may be employed. Alternatively, a process of processing a large area spot laser typified by sopra into a driver circuit size and simultaneously crystallizing an amorphous semiconductor region of the driver circuit may be used.
[0040]
FIG. 4C shows a cross-sectional view of an AM-LCD in which a driver circuit and a pixel portion are integrally formed on the same substrate using the laser beam irradiation method of the present invention. Here, a CMOS circuit is shown as a basic circuit constituting a driver circuit, and a TFT having a double gate structure is shown as a TFT in a pixel portion. Of course, not only the double gate structure but also a triple gate structure or a single gate structure may be used.
[0041]
Reference numeral 202 denotes a silicon oxide film provided as a base film, on which an active layer of a TFT of a driver circuit, an active layer of a TFT of a pixel portion, and a semiconductor layer serving as a lower electrode of a storage capacitor are formed. Note that in this specification, an “electrode” is a part of “wiring” and refers to a portion where electrical connection with another wiring is made or a portion intersecting with a semiconductor layer. Therefore, for convenience of explanation, “wiring” and “electrode” are properly used, but it is assumed that “electrode” is always included in the term “wiring”.
[0042]
In FIG. 4C, the active layer of the driver circuit TFT includes an N-channel TFT (hereinafter referred to as NTFT) source region 221, drain region 220, LDD (lightly doped drain) region 228, and channel formation region 209. In addition, a source region 215, a drain region 216, and a channel formation region 217 of a P-channel TFT (hereinafter referred to as PTFT) are formed.
[0043]
In addition, an active layer of a TFT in the pixel portion (here, NTFT is used) is formed of a source region 222, a drain region 224, an LDD region 229, and a channel formation region 212. Further, a semiconductor layer extended from the drain region 224 is used as the lower electrode 226 of the storage capacitor.
[0044]
In FIG. 1, the lower electrode 226 is directly connected to the drain region 224 of the TFT in the pixel portion. However, the structure is such that the lower electrode 226 and the drain region 224 are electrically connected by being indirectly connected. It is also good.
[0045]
The lower electrode 226 is doped with an element belonging to Group 15 with respect to the semiconductor layer. That is, since it can be used as an electrode as it is without applying a voltage to the upper wiring 206f of the storage capacitor, it is effective in reducing the power consumption of the AM-LCD.
[0046]
In addition, the channel formation region 212 of the TFT in the pixel portion is an amorphous semiconductor film, and the channel formation regions 209 and 217 of the driver circuit TFT are crystalline semiconductor films having crystallinity. one of.
[0047]
Further, the channel formation regions 209, 212, and 217 of each TFT are semiconductor films formed by sputtering, and one of the present invention is that the hydrogen concentration in the films is low. A semiconductor film formed by a sputtering method has a hydrogen concentration that is one digit or more lower than that of a semiconductor film formed by a plasma CVD method, and can be continuously laser-crystallized after film formation without dehydrogenation treatment. On the other hand, the process using the plasma CVD method has a high risk of explosion, which is disadvantageous from the viewpoint of the safety of the working environment. In the present invention, in order to give priority to safety and productivity, thin film formation of an amorphous semiconductor film (amorphous silicon film or the like), an insulating film, a conductive layer or the like is formed by sputtering. More preferably, each film is continuously formed as much as possible in order to prevent contamination from the atmosphere.
[0048]
Here, the gate insulating film 205 of each TFT is the same insulating film having the same thickness, but is not particularly limited. For example, at least two types of TFTs having different gate insulating films on the same substrate according to circuit characteristics may be used. Note that it is preferable to continuously form the semiconductor film and the gate insulating film by a sputtering method because a favorable interface can be obtained.
[0049]
Next, on the gate insulating film 205, a gate wiring 206d of the TFT of the driver circuit and a gate wiring 206e of the TFT of the pixel portion are formed. At the same time, an upper electrode 206 f of the storage capacitor is formed on the lower electrode 226 of the storage capacitor via the gate insulating film 205.
[0050]
As the wiring material of the present invention, typically, a conductive silicon film (eg, phosphorus-doped silicon film, boron-doped silicon film, etc.) or metal film (eg, tungsten film, tantalum film, molybdenum film, titanium film, aluminum film) A silicide film obtained by siliciding the metal film, or a nitrided metal film (such as a tantalum nitride film, a tungsten nitride film, or a titanium nitride film). Moreover, you may laminate | stack combining these freely.
[0051]
When the metal film is used, it is desirable to have a laminated structure with a silicon film in order to prevent oxidation of the metal film. In terms of preventing oxidation, a structure in which a metal film is covered with a silicon nitride film is effective.
[0052]
Next, reference numeral 230 denotes a first interlayer insulating film, which is formed of an insulating film (single layer or stacked layer) containing silicon. As the insulating film containing silicon, a silicon oxide film, a silicon nitride film, a silicon oxynitride film (a nitrogen content is higher than oxygen), a silicon nitride oxide film (an oxygen content is higher than nitrogen) ) Can be used.
[0053]
Then, contact holes are provided in the first interlayer insulating film 230, and source wirings 231 and 233 and drain wirings 232 of the TFT of the driver circuit, and source wiring 234 and drain wiring 235 of the TFT of the pixel portion are formed. A passivation film 236 and a second interlayer insulating film 237 are formed thereon, and a pixel electrode 238 is formed after providing a contact hole.
[0054]
Note that in FIG. 4C, a black mask (light-shielding film) is not formed, but there is no particular limitation and the black mask may be formed as necessary. For example, a light shielding film may be provided on the counter substrate, or a light shielding film using a material similar to that of the gate wiring may be provided below or on each TFT.
[0055]
As the second interlayer insulating film 237, a resin film having a small relative dielectric constant is preferable. As the resin film, a polyimide film, an acrylic film, a polyamide film, a BCB (benzocyclobutene) film, or the like can be used.
[0056]
Further, as the pixel electrode 238, a transparent conductive film typified by an ITO film is used for manufacturing a transmissive AM-LCD, and a reflectivity typified by an aluminum film is used for manufacturing a reflective AM-LCD. A high metal film may be used.
[0057]
In FIG. 4, the pixel electrode 238 is electrically connected to the drain region 224 of the TFT of the pixel portion through the drain electrode 235, but the structure in which the pixel electrode 238 and the drain region 224 are directly connected. It is also good.
[0058]
The AM-LCD having the structure as described above is characterized in that each circuit is formed by a TFT having an appropriate structure according to the function, so that the driving capability, reliability, and productivity are high.
[0059]
The present invention having the above-described configuration will be described in more detail with the following examples.
[0060]
【Example】
[Example 1]
In this example, a manufacturing process for realizing the structure of FIG. 4C described in Embodiment Mode will be described. 2 to 4 are used for the description.
[0061]
First, a glass substrate 201 is prepared as a substrate, and a 200 nm thick silicon oxide film (also referred to as a base film) 202 and a 55 nm thick amorphous silicon film 203a are continuously sputtered without being released to the atmosphere. To form a film. By doing so, it is possible to prevent impurities such as boron contained in the atmosphere from being adsorbed on the lower surface of the amorphous silicon film 203a.
[0062]
In this embodiment, an amorphous silicon film is used as the amorphous semiconductor film, but other semiconductor films may be used. An amorphous silicon germanium film may be used. Further, as a method for forming the base film and the semiconductor film, a PCVD method, an LPCVD method, a sputtering method, or the like can be used. Of these, the sputtering method is desirable because of its excellent safety and productivity. The sputtering apparatus used in this example includes a chamber, an exhaust system that evacuates the chamber, a gas introduction system that introduces a sputtering gas into the chamber, an electrode system including a target, an RF electrode, and the like, And a sputtering power source connected to the system. In this embodiment, argon (Ar) is used as a sputtering gas and a silicon target is used as a target.
[0063]
In this embodiment, the channel formation region of the TFT in the pixel portion is an amorphous silicon film (the field effect mobility μ of the NTFT made of an amorphous silicon film). _FE Is 1.0cm ² Therefore, it is necessary to appropriately set the channel length and the film thickness of the amorphous silicon film.
[0064]
Next, the amorphous silicon film 204a is crystallized. As the crystallization means, known techniques such as laser crystallization and thermal crystallization using a catalytic element are used. In this example, laser crystallization was performed using the laser irradiation method shown in FIG. The laser beam emitted from the excimer laser light source 105 was adjusted in beam shape, energy density, and the like by an optical system (a beam homogenizer 106, a mirror 107, etc.) to form a laser spot 108. Then, the laser spot 108 was irradiated in the laser spot scanning direction 109 only to the amorphous semiconductor film of the driver circuit 103 by moving the XY stage 104 to which the substrate 101 was fixed in the X direction or the Y direction. Thus, only the driver circuit was irradiated with laser to be selectively crystallized to form a region 204a made of a crystalline silicon (polysilicon) film. (Fig. 2 (B))
[0065]
In this embodiment, the channel formation region of the TFT of the driver circuit is a crystalline silicon film (the field effect mobility μ of the NTFT made of a crystalline silicon film). _FE Is 1.0cm ² / Vs or higher), it is necessary to appropriately set the optimum channel length and the thickness of the amorphous silicon film that can be sufficiently laser-crystallized. Taking the above into consideration, the channel length may be 3 to 10 μm, and the film thickness of the amorphous silicon film may be 10 to 200 nm, preferably 30 to 70 nm.
[0066]
Then, the formed crystalline silicon (polysilicon) film is patterned to form a TFT semiconductor layer 204b of the driver circuit, and the amorphous silicon (amorphous silicon) film is patterned to form a TFT semiconductor layer of the pixel portion. 203b was formed. (Fig. 2 (C))
[0067]
An impurity element (phosphorus or boron) is added to the crystalline silicon film before and after forming the semiconductor layers 203b and 204b of the driver circuit TFT and the pixel portion TFT. You may do it. This process may be performed only for NTFT or PTFT, or for both.
[0068]
Next, a gate insulating film 205 is formed by a sputtering method or a plasma CVD method, and a first conductive film 206a and a second conductive film 207a are stacked by a sputtering method. (Fig. 2 (D))
[0069]
The gate insulating film 205 is an insulating film that functions as a gate insulating film of the TFT, and has a thickness of 50 to 200 nm. In this example, a silicon oxide film having a thickness of 100 nm was formed by sputtering using silicon oxide as a target. Further, not only the silicon oxide film but also a stacked structure in which a silicon nitride film is provided over the silicon oxide film, or a silicon oxynitride film in which nitrogen is added to the silicon oxide film may be used.
[0070]
In this embodiment, the amorphous silicon film is laser crystallized and then patterned to form a gate insulating film. However, the process order is not particularly limited, and the amorphous silicon film and the gate are formed. An insulating film may be continuously formed by sputtering, followed by laser crystallization and patterning. When the film is continuously formed by sputtering, good interface characteristics can be obtained.
[0071]
The first conductive film 206a is formed using a conductive material containing an element selected from Ta, Ti, Mo, and W as a main component. The thickness of the first conductive film 206a may be 5 to 50 nm, preferably 10 to 25 nm. On the other hand, the second conductive film 207a is formed using a conductive material containing Al, Cu, or Si as a main component. The second conductive film 207a may be formed with a thickness of 100 to 1000 nm, preferably 200 to 400 nm. The second conductive film 207a is provided to reduce the wiring resistance of the gate wiring or the gate bus line.
[0072]
Next, unnecessary portions of the second conductive film 207a are removed by patterning to form an electrode 207b to be a part of the gate bus line in the wiring portion, and then resist masks 208a to 208d are formed. The resist mask 208a covers the PTFT, and the resist mask 208b is formed so as to cover the channel formation region of the NTFT of the driver circuit. The resist mask 208c covers the electrode 207b, and the resist mask 208d is formed so as to cover the channel formation region of the pixel portion. Thereafter, an impurity element imparting n-type conductivity was added using the resist masks 208a to 208d as masks, whereby impurity regions 210 and 211 were formed. (Fig. 3 (A))
[0073]
In this embodiment, phosphorus is used as an impurity element imparting n-type, and phosphine (PH _Three ) Using an ion doping method. In this step, in order to add phosphorus to the underlying semiconductor layers 203b and 204b through the gate insulating film 205 and the first conductive film 206a, the acceleration voltage was set to 80 keV and high. The concentration of phosphorus added to the semiconductor layers 203b and 204b is 1 × 10 ¹⁶ ~ 1x10 ¹⁹ atoms / cm ^Three In the range of 1 × 10 ¹⁸ atoms / cm ^Three It was. Then, regions 210 and 211 in which phosphorus was added to the semiconductor layer were formed. Part of the region added with phosphorus formed here functions as an LDD region. Further, part of the regions covered with the mask and not doped with phosphorus (the region 209 made of a crystalline silicon film and the region 212 made of an amorphous silicon film) function as a channel formation region.
[0074]
Note that in the phosphorus addition step, an ion implantation method in which mass separation is performed may be used, or a plasma doping method in which mass separation is not performed may be used. The practitioner may set optimum values for the acceleration voltage, the dose amount, and the like.
[0075]
Next, after removing the resist masks 208a to 208d, an activation process is performed if necessary. Then, a third conductive film 213a was formed by sputtering. (FIG. 3B) The third conductive film 213a is formed using a conductive material whose main component is an element selected from Ta, Ti, Mo, and W. The thickness of the third conductive film 213a is 100 to 1000 nm, preferably 200 to 500 nm.
[0076]
Next, after newly forming resist masks 214a to 214d and performing patterning to form the gate electrodes 206b and 213b of the PTFT and the wirings 206c and 213c, p-type is imparted using the masks 214a to 214d as they are. An impurity element to be added is added to form a source region and a drain region of the PTFT. (FIG. 3C) Here, boron is used as the impurity element, and diborane (B ₂ H ₆ ) Using an ion doping method. Again, the acceleration voltage is 80 keV and 2 × 10 ²⁰ atoms / cm ^Three Boron was added to a concentration of.
[0077]
Next, after removing the resist masks 214a to 214d and newly forming resist masks 218a to 218e, etching is performed using the resist masks 218a to 218e as a mask, and the gate wirings 206d and 213d of the NTFT and the gate wiring of the TFT of the pixel portion 206e and 213e and storage capacitor upper wirings 206f and 213f are formed. (Fig. 3 (D))
[0078]
Next, the resist masks 218a to 218e are removed and a new resist mask 219 is formed. Then, an impurity element imparting n-type conductivity is added to the source and drain regions of the NTFT to form impurity regions 220 to 225. (FIG. 4 (A)) Here, the phosphine (PH _Three ) Using an ion doping method. The concentration of phosphorus added to the impurity regions 220 to 225 is higher than that in the previous step of adding the impurity element imparting n-type, and 1 × 10 ¹⁹ ~ 1x10 ^{twenty one} atoms / cm ^Three Is preferred, here 1 × 10 ²⁰ atoms / cm ^Three It was.
[0079]
Thereafter, after removing the resist mask 219, a protective film 227 made of a silicon nitride film having a thickness of 50 nm is formed, and the state shown in FIG. 4B is obtained.
[0080]
Next, activation processing for activating the added impurity element imparting n-type or p-type is performed. This step may be performed by a thermal annealing method using an electric heating furnace, a laser annealing method using the above-described excimer laser, or a rapid thermal annealing method (RTA method) using a halogen lamp. In the case of heat treatment, heat treatment was performed at 300 to 700 ° C., preferably 350 to 550 ° C., and in this embodiment, 450 ° C. in a nitrogen atmosphere for 2 hours.
[0081]
Next, after forming the first interlayer insulating film 230, contact holes are formed, and source and drain electrodes 231 to 235 and the like are formed by a known technique.
[0082]
Thereafter, a passivation film 236 is formed. As the passivation film 236, a silicon nitride film, a silicon oxynitride film, a silicon nitride oxide film, or a stacked film of these insulating films and a silicon oxide film can be used. In this embodiment, a silicon nitride film having a thickness of 300 nm is used as a passivation film.
[0083]
In this embodiment, as a pretreatment for forming the silicon nitride film, a plasma treatment using ammonia gas is performed, and the passivation film 236 is formed as it is. Since the hydrogen activated (excited) by the plasma by this pretreatment is confined by the passivation film 236, the hydrogen termination of the active layer (semiconductor layer) of the TFT can be promoted.
[0084]
Further, when a nitrous oxide gas is added in addition to a gas containing hydrogen, the surface of the object to be processed is cleaned by the generated moisture, and contamination by boron or the like contained in the atmosphere can be effectively prevented.
[0085]
After the passivation film 236 was formed, an acrylic film having a thickness of 1 μm was formed as the second interlayer insulating film 237 and then patterned to form a contact hole, thereby forming a pixel electrode 238 made of an ITO film. Thus, an AM-LCD having a structure as shown in FIG. 4C is completed.
[0086]
Through the above steps, the channel forming region 209, the impurity regions 220 and 221 and the LDD region 228 are formed in the NTFT of the driver circuit. The impurity region 220 is a source region, and the impurity region 221 is a drain region. Further, a channel formation region 212, impurity regions 222 to 225, and an LDD region 229 are formed in the NTFT of the pixel portion. Here, in the LDD regions 228 and 229, a region overlapping with the gate electrode (GOLD region) and a region not overlapping with the gate electrode (LDD region) were formed, respectively.
[0087]
On the other hand, in the p-channel TFT, a channel formation region 217 and impurity regions 215 and 216 are formed. The impurity region 215 serves as a source region, and the impurity region 216 serves as a drain region.
[0088]
As described above, the present invention includes a TFT of a pixel portion having a channel formation region 212 made of an amorphous silicon film and a TFT of a driver circuit having channel formation regions 209 and 217 made of a crystalline silicon film on the same substrate. There is a feature in the point to form. With such a structure, it is possible to form a TFT of a pixel portion with high uniformity and a TFT of a driver circuit with high mobility on the same substrate.
[0089]
FIG. 5A illustrates an example of a circuit configuration of an active matrix liquid crystal display device. The active matrix liquid crystal display device of this embodiment includes a source signal line driver circuit 301, a gate signal line driver circuit (A) 307, a gate signal line driver circuit (B) 311, a precharge circuit 312, and a pixel portion 306. have.
[0090]
The source signal line side driver circuit 301 includes a shift register circuit 302, a level shifter circuit 303, a buffer circuit 304, and a sampling circuit 305.
[0091]
The gate signal line side driver circuit (A) 307 includes a shift register circuit 308, a level shifter circuit 309, and a buffer circuit 310. The gate signal line side driver circuit (B) 311 has the same configuration.
[0092]
In the present invention, a semiconductor layer in the region is crystallized using a circuit other than the pixel portion as a driver circuit, but is not particularly limited. That is, among driver circuits, a circuit that requires higher reliability than high mobility may not be crystallized. For example, among the driver circuits, the buffer circuit or the like may be configured with an amorphous semiconductor layer in the channel formation region, similar to the NTFT in the pixel portion.
[0093]
Further, in the present invention, it is easy to make the length of the LDD region different on the same substrate in consideration of the driving voltage of the NTFT, and the optimum shape is set for the TFTs constituting each circuit in the same process. It can also be built in.
[0094]
FIG. 5B is a top view of the pixel portion, and the AA ′ cross-sectional structure of the TFT portion and the BB ′ cross-sectional structure of the wiring portion correspond to FIG. 4C. Parts are denoted by the same reference numerals. In FIG. 5B, 401 denotes a semiconductor layer, 402 denotes a gate electrode, and 403a denotes a capacitor line. In this embodiment, the gate electrode and the gate wiring 403b are formed of a first conductive layer and a third conductive layer, and the gate bus line is formed of the first conductive layer, the second conductive layer, and the third conductive layer. And a clad structure formed from the layers.
[0095]
FIG. 10A shows a top view of a CMOS circuit which is a part of the driver circuit, and corresponds to FIG. In this embodiment, the NTFT and PTFT active layers are in direct contact with each other and share the drain electrode. However, the present invention is not limited to this structure, and the structure shown in FIG. 10B (the active layer is completely separated). ).
[0096]
[Example 2]
In this embodiment, an example in which an amorphous semiconductor film is selectively crystallized using a laser different from that in Embodiment 1 will be described below with reference to FIGS. Since this example is the same as Example 1 except for the laser crystallization step, only the different points will be described.
[0097]
First, according to the manufacturing process of Example 1, a silicon oxide film (underlying film) and an amorphous silicon film are continuously formed on a substrate. In this embodiment, a quartz substrate is used as the substrate. The film thickness of the amorphous silicon film is preferably 100 nm or more because of the absorption coefficient of the argon laser.
[0098]
Next, in laser crystallization, crystallization is selectively performed using the irradiation method shown in FIG. The laser light emitted from the argon laser light source 605 was adjusted in beam shape, energy density, and the like by an optical system (beam expander 606, galvanometer 607, f-theta lens 608, etc.) to form a laser spot 609. Then, by vibrating the galvanometer, the laser spot 609 is vibrated in a direction parallel to the laser spot scanning direction 610, and at the same time, the uniaxial operation stage 604 to which the substrate 601 is fixed is moved in one direction (operation direction 611 of the uniaxial operation stage). By performing step movement (the step interval is about the spot diameter), only the driver circuit was irradiated with laser to be selectively crystallized to form a region made of a crystalline silicon (polysilicon) film.
[0099]
If the subsequent steps are in accordance with Example 1, the state shown in FIG. 4C can be obtained.
[0100]
Example 3
In the manufacturing steps shown in Examples 1 and 2, only the driver circuit is selectively irradiated using the laser irradiation method shown in FIG. 1 or 2, but the laser light is selected using a normal resist mask. It is also possible to irradiate automatically.
[0101]
In this case, a conventional laser irradiation apparatus can be used as it is. Therefore, it can be said to be an effective technique because it can be easily performed without changing the apparatus.
[0102]
Moreover, the structure of a present Example can be freely combined with any Example of Example 1-2.
[0103]
Example 4
In this embodiment, an example in which an AM-LCD is manufactured through a process different from that in Embodiment 1 will be described with reference to FIGS. In Example 1, an example of a top gate type TFT is shown, but in this example, an example of a bottom gate type TFT is shown.
[0104]
First, a gate electrode 702 having a stacked structure (not shown for simplicity) is formed over a glass substrate 701. In this embodiment, a tantalum nitride film and a tantalum film are stacked by sputtering, and gate wirings (including gate electrodes) 702a to 702c and capacitor wiring 702d are formed by known patterning.
[0105]
Next, a gate insulating film and an amorphous semiconductor film were sequentially stacked without being exposed to the atmosphere. In this embodiment, a stacked layer of a silicon nitride film and a silicon oxide film is formed by sputtering to form a stacked gate insulating film. (FIG. 7A) Next, an amorphous silicon film was formed by sputtering without opening to the atmosphere. Although an amorphous semiconductor film formed by a sputtering method has a low hydrogen concentration, heat treatment for further reducing the hydrogen concentration may be performed.
[0106]
In this embodiment, the channel formation region of the TFT in the pixel portion is an amorphous silicon film (the field effect mobility μ of the NTFT made of an amorphous silicon film). _FE Is 1.0cm ² Therefore, it is necessary to appropriately set the channel length and the film thickness of the amorphous silicon film.
[0107]
Next, laser crystallization was selectively performed to form a crystalline silicon film 706. In this embodiment, only the driver circuit was irradiated with laser light using the laser irradiation method shown in FIG. (Fig. 7 (B))
[0108]
In this embodiment, the channel formation region of the TFT of the driver circuit is a crystalline silicon film (the field effect mobility μ of the NTFT made of a crystalline silicon film). _FE Is 1.0cm ² / Vs or higher), it is necessary to appropriately set the optimum channel length and the thickness of the amorphous silicon film that can be sufficiently laser-crystallized. Taking the above into consideration, the channel length may be 3 to 10 μm, and the film thickness of the amorphous silicon film may be 10 to 200 nm, preferably 30 to 70 nm.
[0109]
Next, a channel protective film 707 that protects the channel formation region is formed. This channel protective film 707 may be formed using known patterning. In this example, patterning was performed using a photomask. In this state, the surface of the crystalline silicon film or the amorphous silicon film other than the region in contact with the channel protective film 707 is exposed. (FIG. 7C) In addition, when patterning is performed using exposure from the back surface, a photomask is not necessary, so that the number of steps can be reduced.
[0110]
Next, a resist mask 708 covering a part of the PTFT and NTFT was formed by patterning using a photomask. Next, an impurity element imparting n-type conductivity (phosphorus in this embodiment) was added to form an impurity region 709. (Fig. 8 (A))
[0111]
Next, after removing the resist mask 708, the entire surface was covered with a thin insulating film. This thin insulating film is formed in order to add an impurity element at a low concentration and is not particularly necessary. (Fig. 8 (B))
[0112]
Next, the impurity element was added at a low concentration compared to the previous impurity element addition step. (FIG. 8C) The crystalline silicon film covered with the channel protective film 707 by this process becomes the channel formation region 713, and the amorphous silicon film covered with the channel protection film 707 becomes the channel formation region 714. Also, NTD LDD regions 711 and 712 were formed by this process.
[0113]
Next, a resist mask 715 covering the entire surface of the N-channel TFT was formed, and an impurity element imparting p-type was added. (FIG. 8D) The crystalline silicon film covered with the channel protective film 707 by this step becomes the channel formation region 716 of the PTFT, and the source region and the drain region 717 of the PTFT are formed by this step.
[0114]
Next, after removing the resist mask 715, the semiconductor layer was patterned into a desired shape. (Fig. 9 (A))
[0115]
Next, after forming the first interlayer insulating film 722, contact holes are formed, and source and drain electrodes 723 to 727 and the like are formed by a known technique.
[0116]
Thereafter, a passivation film 728 is formed. As the passivation film 728, a silicon nitride film, a silicon oxynitride film, a silicon nitride oxide film, or a stacked film of these insulating films and a silicon oxide film can be used. In this embodiment, a silicon nitride film having a thickness of 300 nm is used as a passivation film.
[0117]
In this embodiment, as a pretreatment for forming the silicon nitride film, a plasma treatment using ammonia gas is performed, and the passivation film 728 is formed as it is. Since the hydrogen activated (excited) by the plasma by this pretreatment is confined by the passivation film 728, the hydrogen termination of the active layer (semiconductor layer) of the TFT can be promoted.
[0118]
After the passivation film 728 was formed, an acrylic film having a thickness of 1 μm was formed as the second interlayer insulating film 729 and then patterned to form a contact hole, thereby forming a pixel electrode 730 made of an ITO film. Thus, an AM-LCD having a structure as shown in FIG. 9C is completed.
[0119]
In addition, the configuration of this embodiment can be freely combined with any of the embodiments 2 and 3.
[0120]
Example 5
In this embodiment, a case where another means is used for forming the crystalline silicon film in Embodiment 1 will be described.
[0121]
Specifically, the technique described in Example 2 of Japanese Patent Laid-Open No. 7-130652 (corresponding to US Pat. No. 08 / 329,644) is used for crystallization of the amorphous silicon film. The technique described in the publication selectively holds a catalytic element (cobalt, palladium, germanium, platinum, iron, copper, typically nickel) that promotes crystallization on the surface of the amorphous silicon film, This is a technique for performing crystallization using this part as a seed for nuclear growth.
[0122]
According to this technique, since the crystal growth can have a specific direction, it is possible to form a crystalline silicon film having very high crystallinity.
[0123]
In addition, the structure of a present Example can be freely combined with any structure of Examples 1-4.
[0124]
Example 6
In this embodiment, a case where another means is used for forming the crystalline silicon film in Embodiment 1 will be described.
[0125]
In this embodiment, nickel is selected as the catalyst element, a layer containing nickel is formed on the amorphous silicon film, and a process of selectively irradiating with laser light is performed for crystallization.
[0126]
Next, a resist mask is formed on the silicon film, and an element belonging to Group 15 (phosphorus in this embodiment) is added. The concentration of phosphorus to be added is 5 × 10 ¹⁸ ~ 1x10 ²⁰ atoms / cm ^Three (Preferably 1 × 10 ¹⁹ ~ 5x10 ¹⁹ atoms / cm ^Three ) Is preferred. However, the concentration of phosphorus to be added is not limited to this concentration range because it varies depending on the temperature and time of the subsequent gettering step and the area of the phosphorus-doped region. Thus, a region to which phosphorus was added (hereinafter referred to as a phosphorus-doped region) was formed.
[0127]
The resist mask is disposed so as to expose a part (or all) of a region that later becomes a source region or a drain region of the TFT of the driver circuit. Similarly, the resist mask is disposed so as to expose part (or all) of the source region or drain region of the TFT in the pixel portion later. At this time, since a resist mask is not disposed in the region that becomes the lower electrode of the storage capacitor, phosphorus is added to the entire surface to form a phosphorus-doped region.
[0128]
Next, the resist mask is removed, and heat treatment at 500 to 650 ° C. is applied for 2 to 16 hours to getter the catalyst element (nickel in this embodiment) used for crystallization of the silicon film. In order to achieve the gettering action, a temperature of about ± 50 ° C. from the maximum temperature of the thermal history is necessary, but since the heat treatment for crystallization is performed at 550 to 600 ° C., the heat treatment at 500 to 650 ° C. is sufficient. The gettering action can be achieved.
[0129]
Then, the crystalline silicon (polysilicon) film in which the catalytic element was reduced was patterned to form a crystalline semiconductor layer of the driver circuit TFT and an amorphous semiconductor layer of the TFT of the pixel portion. The subsequent steps may be performed according to the first embodiment.
[0130]
In addition, the structure of a present Example can be freely combined with any structure of Examples 1-5.
[0131]
Example 7
In this embodiment, an example in which a source region and a drain region are formed by adding an element belonging to Group 13 or Group 15 in an order different from that in Embodiment 1 will be described. In the present invention, the doping order can be changed as appropriate. In the doping order of Example 1, low concentration phosphorus was added first, boron was added second, and high concentration phosphorus was added third, but in this example, FIG. After obtaining the state of B), an example of adding a high concentration of phosphorus first is shown.
[0132]
First, the state shown in FIG.
[0133]
Next, a resist mask for forming the NTFT wiring is formed. This resist mask covers the PTFT. Etching is performed using this resist mask as a mask to form the gate wiring of the NTFT, the gate wiring of the TFT in the pixel portion, and the upper wiring of the storage capacitor.
[0134]
Next, after removing the resist mask and forming a new resist mask, an impurity element imparting n-type conductivity is added to the source region and drain region of the NTFT to form impurity regions. At this time, the concentration of added phosphorus is 5 × 10. ¹⁹ ~ 1x10 ^{twenty one} atoms / cm ^Three It is.
[0135]
Next, a resist mask that covers a region other than the PTFT is formed. Then, a boron addition step is performed. At this time, the concentration of added boron is 1 × 10. ²⁰ ~ 3x10 ^{twenty one} atoms / cm ^Three It is. Thus, the source region, drain region, and channel forming region of the PTFT are defined.
[0136]
The following steps may follow the manufacturing steps of Example 1. The configuration of the present embodiment can be freely combined with any of the first to sixth embodiments.
[0137]
Example 8
The present invention can also be used when an interlayer insulating film is formed on a conventional MOSFET and a TFT is formed thereon. That is, it is also possible to realize a three-dimensional semiconductor device in which a reflective AM-LCD is formed on a semiconductor circuit.
[0138]
The semiconductor circuit may be formed on an SOI substrate such as SIMOX, Smart-Cut (registered trademark of SOITEC), ELTRAN (registered trademark of Canon Inc.), or the like.
[0139]
In addition, when implementing a present Example, you may combine any structure of Examples 1-7.
[0140]
Example 9
In this embodiment, a case will be described in which a TFT is formed on a substrate in the manufacturing process shown in Embodiment 1 and an AM-LCD is actually manufactured.
[0141]
When the state of FIG. 4C is obtained, an alignment film is formed on the pixel electrode 238 to a thickness of 80 nm. Next, a glass substrate with a color filter, a transparent electrode (counter electrode), and an alignment film formed thereon is prepared as a counter substrate, and each alignment film is rubbed and a sealing material (sealing material) is used. The substrate on which the TFT is formed is bonded to the counter substrate. In the meantime, the liquid crystal is held. Since this cell assembling process may use a known means, a detailed description thereof will be omitted.
[0142]
In addition, what is necessary is just to provide the spacer for maintaining a cell gap as needed. Therefore, when the cell gap can be maintained without the spacer as in the AM-LCD having a diagonal of 1 inch or less, it is not particularly necessary.
[0143]
Next, the appearance of the AM-LCD manufactured as described above is shown in FIG. As shown in FIG. 11, the active matrix substrate and the counter substrate face each other, and liquid crystal is sandwiched between these substrates. The active matrix substrate includes a pixel portion 1001, a scanning line driver circuit 1002, and a signal line driver circuit 1003 formed over the substrate 1000.
[0144]
The scan line driver circuit 1002 and the signal line driver circuit 1003 are connected to the pixel portion 1001 by a scan line 1030 and a signal line 1040, respectively. These driver circuits 1002 and 1003 are mainly composed of CMOS circuits.
[0145]
A scanning line is formed for each row of the pixel portion 1001, and a signal line 1040 is formed for each column. A TFT 1010 in the pixel portion is formed in the vicinity of the intersection of the scanning line 1030 and the signal line 1040. The gate electrode of the TFT 1010 in the pixel portion is connected to the scanning line 1030 and the source is connected to the signal line 1040. Further, a pixel electrode 1060 and a storage capacitor 1070 are connected to the drain.
[0146]
The counter substrate 1080 has a transparent conductive film such as an ITO film formed on the entire surface of the substrate. The transparent conductive film is a counter electrode with respect to the pixel electrode 1060 of the pixel portion 1001, and the liquid crystal material is driven by an electric field formed between the pixel electrode and the counter electrode. On the counter substrate 1080, an alignment film, a black mask, and a color filter are formed as necessary.
[0147]
IC chips 1032 and 1033 are attached to the substrate on the active matrix substrate side using the surface to which the FPC 1031 is attached. These IC chips 1032 and 1033 are formed by forming circuits such as a video signal processing circuit, a timing pulse generation circuit, a γ correction circuit, a memory circuit, and an arithmetic circuit on a silicon substrate.
[0148]
Further, in this embodiment, the liquid crystal display device is described as an example. However, the present invention is applied to an EL (electroluminescence) display device and an EC (electrochromic) display device if the display device is an active matrix type. It is also possible to do.
[0149]
In addition, a present Example can be freely combined with any Example of Examples 1-8.
[0150]
Example 10
In this embodiment, an example of manufacturing an active matrix EL display device using the present invention is shown in FIGS.
[0151]
FIG. 12 is a simplified circuit diagram of an active matrix EL display device. Reference numeral 11 denotes a pixel portion, and an X direction driver circuit 12 and a Y direction driver circuit 13 are provided around the pixel portion. Each pixel of the pixel unit 11 includes a switching TFT 14, a capacitor 15, a current control TFT 16, and an organic EL element 17, and the switching TFT 14 has an X direction signal line 18a (or 18b) and a Y direction signal line 20a ( Or 20b, 20c) are connected. Further, power supply lines 19 a and 19 b are connected to the current control TFT 16.
[0152]
In this embodiment, the TFT semiconductor layer used in the X-direction driver circuit 12 and the Y-direction driver circuit 13 is formed of polysilicon, and the TFT semiconductor layer used in the pixel portion 11 is formed of amorphous silicon.
[0153]
The TFT structure used in the X-direction driver circuit 12 and the Y-direction driver circuit 13 is a GOLD structure, and the TFT structures of the switching TFT 14 and the current control TFT 16 are LDD structures.
[0154]
FIG. 13A is a top view of an EL display device using the present invention. In FIG. 13A, reference numeral 4010 denotes a substrate, 4011 denotes a pixel portion, 4012 denotes a source side driver circuit, and 4013 denotes a gate side driver circuit. Connected.
[0155]
At this time, a cover material 6000, a sealing material (also referred to as a housing material) 7000, and a sealing material (second sealing material) 7001 are provided so as to surround at least the pixel portion, preferably the drive circuit and the pixel portion.
[0156]
FIG. 13B shows a cross-sectional structure of the EL display device of this embodiment. A driving circuit TFT (here, an n-channel TFT and a p-channel TFT are combined on a substrate 4010 and a base film 4021). And the pixel portion TFT 4023 (however, only the TFT for controlling the current to the EL element is shown here). Here, an example using bottom gate TFTs by the manufacturing method shown in Embodiment 4 is shown; however, there is no particular limitation, and these TFTs may have a known structure (top gate structure or bottom gate structure).
[0157]
When the driving circuit TFT 4022 having an active layer made of a crystalline semiconductor film and the pixel portion TFT 4023 having an active layer made of an amorphous semiconductor film are completed using the present invention, an interlayer insulating film made of a resin material (flat A pixel electrode 4027 made of a transparent conductive film that is electrically connected to the drain of the pixel portion TFT 4023 is formed on the oxide film 4026. As the transparent conductive film, a compound of indium oxide and tin oxide (referred to as ITO) or a compound of indium oxide and zinc oxide can be used. After the pixel electrode 4027 to be an anode is formed, an insulating film 4028 is formed, and an opening is formed over the pixel electrode 4027.
[0158]
Next, an EL layer 4029 is formed. The EL layer 4029 may have a stacked structure or a single-layer structure by freely combining known EL materials (a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, or an electron injection layer). A known technique may be used to determine the structure. EL materials include low-molecular materials and high-molecular (polymer) materials. When a low molecular material is used, a vapor deposition method is used. When a high molecular material is used, a simple method such as a spin coating method, a printing method, or an ink jet method can be used.
[0159]
In this embodiment, the EL layer is formed by vapor deposition using a shadow mask. Color display is possible by forming a light emitting layer (a red light emitting layer, a green light emitting layer, and a blue light emitting layer) capable of emitting light having different wavelengths for each pixel using a shadow mask. In addition, there are a method in which a color conversion layer (CCM) and a color filter are combined, and a method in which a white light emitting layer and a color filter are combined, but either method may be used. Needless to say, an EL display device emitting monochromatic light can also be used.
[0160]
After the EL layer 4029 is formed, a cathode 4030 is formed thereon. It is desirable to remove moisture and oxygen present at the interface between the cathode 4030 and the EL layer 4029 as much as possible. Therefore, it is necessary to devise such that the EL layer 4029 and the cathode 4030 are continuously formed in a vacuum, or the EL layer 4029 is formed in an inert atmosphere and the cathode 4030 is formed without being released to the atmosphere. In this embodiment, the above-described film formation is possible by using a multi-chamber type (cluster tool type) film formation apparatus.
[0161]
In this embodiment, a stacked structure of a LiF (lithium fluoride) film and an Al (aluminum) film is used as the cathode 4030. Specifically, a 1 nm-thick LiF (lithium fluoride) film is formed on the EL layer 4029 by evaporation, and a 300 nm-thick aluminum film is formed thereon. Of course, you may use the MgAg electrode which is a well-known cathode material. The cathode 4030 is connected to the wiring 4016 in the region indicated by 4031. A wiring 4016 is a power supply line for applying a predetermined voltage to the cathode 4030, and is connected to the FPC 4017 through a conductive paste material 4032.
[0162]
In order to electrically connect the cathode 4030 and the wiring 4016 in the region indicated by 4031, it is necessary to form contact holes in the interlayer insulating film 4026 and the insulating film 4028. These may be formed when the interlayer insulating film 4026 is etched (when the pixel electrode contact hole is formed) or when the insulating film 4028 is etched (when the opening before the EL layer is formed). In addition, when the insulating film 4028 is etched, the interlayer insulating film 4026 may be etched all at once. In this case, if the interlayer insulating film 4026 and the insulating film 4028 are the same resin material, the shape of the contact hole can be improved.
[0163]
A passivation film 6003, a filler 6004, and a cover material 6000 are formed so as to cover the surface of the EL element thus formed.
[0164]
Further, a sealing material is provided inside the cover material 6000 and the substrate 4010 so as to surround the EL element portion, and a sealing material (second sealing material) 7001 is formed outside the sealing material 7000.
[0165]
At this time, the filler 6004 also functions as an adhesive for bonding the cover material 6000. As the filler 6004, PVC (polyvinyl chloride), epoxy resin, silicone resin, PVB (polyvinyl butyral) or EVA (ethylene vinyl acetate) can be used. It is preferable to provide a desiccant inside the filler 6004 because the moisture absorption effect can be maintained.
[0166]
In addition, a spacer may be included in the filler 6004. At this time, the spacer may be a granular material made of BaO or the like, and the spacer itself may be hygroscopic.
[0167]
In the case where a spacer is provided, the passivation film 6003 can relieve the spacer pressure. In addition to the passivation film, a resin film for relaxing the spacer pressure may be provided.
[0168]
As the cover material 6000, a glass plate, an aluminum plate, a stainless steel plate, an FRP (Fiberglass-Reinforced Plastics) plate, a PVF (polyvinyl fluoride) film, a mylar film, a polyester film, or an acrylic film can be used. Note that when PVB or EVA is used as the filler 6004, it is preferable to use a sheet having a structure in which an aluminum foil of several tens of μm is sandwiched between PVF films or Mylar films.
[0169]
However, the cover material 6000 needs to have translucency depending on the light emission direction (light emission direction) from the EL element.
[0170]
The wiring 4016 is electrically connected to the FPC 4017 through a gap between the sealing material 7000 and the sealing material 7001 and the substrate 4010. Note that although the wiring 4016 has been described here, the other wirings 4014 and 4015 are electrically connected to the FPC 4017 through the sealing material 7000 and the sealing material 7001 in the same manner.
[0171]
In this embodiment, since the pixel electrode is an anode, it is preferable to use PTFT as the current control TFT. For the manufacturing process, Example 4 may be referred to.
In this embodiment, light generated in the light emitting layer is emitted toward the substrate on which the TFT is formed. Moreover, you may form using the NTFT of this invention. When NTFT is used as the current control TFT, a pixel electrode (cathode of an EL element) made of a highly reflective conductive film is connected to the drain of the pixel portion TFT 4023, and the EL layer is made of a light-transmitting conductive film. What is necessary is just to produce an anode sequentially. In this case, the light generated in the light emitting layer is emitted toward the substrate on which the TFT is not formed.
[0172]
In addition, a present Example can be freely combined with any Example of Examples 1-8.
[0173]
Example 11
The CMOS circuit and the pixel portion formed by implementing the present invention can be used for various electro-optical devices (active matrix liquid crystal display device, active matrix EL display device, active matrix EC display device). That is, the present invention can be implemented in all electronic devices in which these electro-optical devices are incorporated as display units.
[0174]
Such electronic devices include video cameras, digital cameras, projectors (rear type or front type), head mounted displays (goggles type displays), car navigation systems, personal computers, personal digital assistants (mobile computers, mobile phones or electronic books). Etc.). Examples of these are shown in FIGS.
[0175]
FIG. 14A illustrates a personal computer, which includes a main body 2001, an image input portion 2002, a display portion 2003, a keyboard 2004, and the like. The present invention can be applied to the image input unit 2002, the display unit 2003, and other signal driving circuits.
[0176]
FIG. 14B illustrates a video camera, which includes a main body 2101, a display portion 2102, an audio input portion 2103, operation switches 2104, a battery 2105, an image receiving portion 2106, and the like. The present invention can be applied to the display portion 2102 and other signal driving circuits.
[0177]
FIG. 14C illustrates a mobile computer, which includes a main body 2201, a camera unit 2202, an image receiving unit 2203, operation switches 2204, a display unit 2205, and the like. The present invention can be applied to the display portion 2205 and other signal driving circuits.
[0178]
FIG. 14D shows a part (right side) of a head-mounted display, which includes a main body 2301, a signal cable 2302, a head fixing band 2303, a display portion 2304, an optical system 2305, a display device 2306, and the like. The present invention can be used for the display device 2306.
[0179]
FIG. 14E shows a player using a recording medium (hereinafter referred to as a recording medium) on which a program is recorded, and includes a main body 2401, a display portion 2402, a speaker portion 2403, a recording medium 2404, an operation switch 2405, and the like. This player uses a DVD (Digital Versatile Disc), CD, or the like as a recording medium, and can perform music appreciation, movie appreciation, games, and the Internet. The present invention can be applied to the display portion 2402 and other signal driving circuits.
[0180]
FIG. 14F illustrates a digital camera, which includes a main body 2501, a display portion 2502, an eyepiece portion 2503, an operation switch 2504, an image receiving portion (not shown), and the like. The present invention can be applied to the display portion 2502 and other signal driving circuits.
[0181]
FIG. 15A illustrates a mobile phone, which includes a main body 2901, an audio output portion 2902, an audio input portion 2903, a display portion 2904, operation switches 2905, an antenna 2906, and the like. The present invention can be applied to the audio output unit 2902, the audio input unit 2903, the display unit 2904, and other signal driving circuits.
[0182]
FIG. 15B illustrates a portable book (electronic book), which includes a main body 3001, display portions 3002 and 3003, a storage medium 3004, operation switches 3005, an antenna 3006, and the like. The present invention can be applied to the display portions 3002 and 3003 and other signal circuits.
[0183]
FIG. 15C illustrates a display, which includes a main body 3101, a support base 3102, a display portion 3103, and the like. The present invention can be applied to the display portion 3103. The display of the present invention is particularly advantageous when the screen is enlarged, and is advantageous for displays having a diagonal of 10 inches or more (particularly 30 inches or more).
[0184]
As described above, the application range of the present invention is extremely wide and can be applied to electronic devices in various fields. Moreover, the electronic apparatus of a present Example is realizable even if it uses the structure which consists of what combination of Examples 1-10.
[0185]
【The invention's effect】
By using the present invention, each circuit of an electro-optical device typified by an AM-LCD or an EL display device can be formed with a TFT having an appropriate structure according to the function, and an electro-optical device having high reliability can be realized. .
[Brief description of the drawings]
FIG. 1 shows a laser irradiation method of the present invention.
FIGS. 2A and 2B are diagrams illustrating a manufacturing process of an AM-LCD. FIGS.
3A and 3B are diagrams illustrating a manufacturing process of an AM-LCD.
4A and 4B are diagrams illustrating a manufacturing process of an AM-LCD.
FIG. 5 is a top view of a pixel portion and a diagram showing a circuit arrangement.
FIG. 6 shows a laser irradiation method of the present invention.
7A and 7B are diagrams illustrating a manufacturing process of an AM-LCD.
FIGS. 8A to 8C are diagrams illustrating a manufacturing process of an AM-LCD. FIGS.
FIGS. 9A and 9B are diagrams illustrating a manufacturing process of an AM-LCD. FIGS.
FIG. 10 is a top view of a CMOS circuit.
FIG. 11 is a diagram showing an external appearance of an AM-LCD.
FIG. 12 is a circuit diagram of an active matrix EL display device.
FIG. 13 is an external view of an active matrix EL display device.
FIG 14 illustrates an example of an electronic device.
FIG 15 illustrates an example of an electronic device.

Claims (2)

A method for manufacturing a semiconductor device having a driver circuit using a crystalline semiconductor film and a pixel portion using an amorphous semiconductor film,
After a layer containing an element that promotes crystallization is formed over the amorphous semiconductor film, a portion of the amorphous semiconductor film is made a crystalline semiconductor film by selectively irradiating laser light, and another one is formed. Leaving the portion as the amorphous semiconductor film,
Of the crystalline semiconductor film and the amorphous semiconductor film, a first region that becomes a source region or a drain region of a thin film transistor, and a second region that becomes a lower electrode of a storage capacitor in the amorphous semiconductor film. Adding an element belonging to Group 15;
Heat treatment is performed on the crystalline semiconductor film and the amorphous semiconductor film, and the element that promotes crystallization is gettered to the first region and the second region to which the element belonging to the group 15 is added. Process,
After said gettering to step, p-channel driver circuit using the addition of element imparting p-type to n-channel type thin film transistor and the crystalline semiconductor film of the driver circuit using the crystalline semiconductor film the method for manufacturing a semiconductor device which is characterized in that the thin film transistor, and forming a, a thin film transistor及beauty hold capacitance of the pixel portion using the amorphous semiconductor film. In claim 1 ,
The method for manufacturing a semiconductor device, wherein the laser beam is a spot laser beam or a linear laser beam.

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