JP2003273361A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device having a high-performance transistor for peripheral driving circuit, and a manufacturing method thereof. <P>SOLUTION: In a driving circuit 11 for driving peripheral devices, a base conductive film 23 is formed on a quartz substrate 21, a first interlayer insulating film 24 is formed on the film 23; a semiconductor layer 25 to be a channel region 29a, a second interlayer insulating film 26 and a gate electrode 28 are successively laminated on the film 24; and the film 23 is electrically connected to a gate electrode 28 of a TFT (thin film transistor) 41 for driving peripheral devices, thereby manufacturing a driver monolithic type active matrix circuit substrate 1. The substrate 1 manufactured in this way has the high-performance TFT 41 which is provided with high mobility and high on-characteristics. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and its manufacturing method.

[0002]

2. Description of the Related Art Among liquid crystal display devices which are thin and have low power consumption, an active matrix liquid crystal display device using a thin film transistor (TFT) as a driving element has a high contrast and a high response speed. Since it has high performance such as high speed, it is mainly used for a display unit such as a personal computer and a portable television device and the like, and its market size has been greatly expanded in recent years.

Conventionally, amorphous silicon (elemental symbol: Si) is formed in the channel region which is the active region of the TFT.
Although amorphous silicon (hereinafter abbreviated as “a-Si”) is used as a material, polycrystalline silicon (hereinafter abbreviated as “poly-Si”), which is crystalline silicon, is used in the channel region in recent years. A liquid crystal display device using the used high-performance TFT has been developed. By using polycrystalline silicon in the channel region, the pixel TFT of the display section and the driving electronic circuit (hereinafter, simply referred to as “peripheral drive circuit”) arranged in the periphery of the display section are formed on the same substrate. A so-called driver monolithic liquid crystal display device, which was manufactured at the same time, was realized, and is attracting attention as a promising future product.

The driver monolithic liquid crystal display device is used in a projection device because it can be miniaturized. A liquid crystal display device for a projection device is required to be small in size and have high brightness and high definition, and thus requires a particularly high technology among liquid crystal display devices.

The projection device allows a small liquid crystal display device to pass very strong light to display on a screen or the like. According to the progress of miniaturization and high brightness of the projection device, a liquid crystal display device is provided. High light resistance is required for the display device. A-Si or poly- which forms a pixel TFT provided in the display portion of a liquid crystal display device
When light is incident on a silicon film such as Si, a current easily flows due to the photoconductive effect, and the TFT is turned off in the off state.
The off current, which is a current flowing in the pixel electrode, increases, and it becomes difficult to maintain the potential of the pixel electrode, so that the display quality such as contrast deteriorates.

The driver monolithic type liquid crystal display device is constituted by including a semiconductor device in which the above-mentioned pixel TFT of the display section and a peripheral drive circuit are formed on a substrate. A driver monolithic active matrix circuit board 5 is shown as an example of a semiconductor device used for a driver monolithic liquid crystal display device. FIG. 14 is a sectional view showing a schematic configuration of the driver monolithic active matrix circuit board 5. In FIG. 14, a plurality of pixel electrodes 79 arranged in a matrix and each pixel electrode 7 are arranged.
Display unit 5 including a plurality of pixel TFTs 82 connected to
2 and a part of the peripheral drive circuit section 51 provided around the display section 52 and including the peripheral drive circuit TFT 81.

As shown in FIG. 14, in the driver monolithic active matrix circuit substrate 5, a peripheral drive circuit TFT 81 and a pixel TFT 82 are provided on a transparent substrate 61 via a first interlayer insulating film 63. Are formed. Peripheral drive circuit TFT 81 and pixel TFT 8
2 is a source region 64 and a drain region 66 to which impurities are added, and a channel region 6 to which impurities are not added.
And a gate insulating film 6 on the upper side of the semiconductor layer 80 having
A gate electrode 68 is provided via Gate electrode 68
On the upper layer side, a source electrode 73 electrically connected to the source region 64 by the source electrode contact hole 71 and a drain region 66 electrically by the drain electrode contact hole 72 via the second interlayer insulating film 70. And a drain electrode 74 connected to. In the display section 52, the upper light-shielding film 76 is provided on the upper layer side of the source electrode 73 and the drain electrode 74 with the third interlayer insulating film 75 interposed therebetween.
And a pixel electrode contact hole 78 is formed on the upper layer side of the upper layer light-shielding film 76 through a fourth interlayer insulating film 77.
The drain electrode 7 is formed by the conductive film 90 formed on the surface of the
A pixel electrode 79 having a light-transmitting property that is electrically connected to the pixel electrode 4 is formed. Here, the pixel electrode contact hole 7
The surface of No. 8 is the surface of the third interlayer insulating film 75 and the fourth interlayer insulating film 77 facing the pixel electrode contact hole 78.

An auxiliary capacitance electrode 69 is formed on the display section 52. In the liquid crystal display device using the driver monolithic active matrix circuit substrate 5, the pixel electrode 79 provided on the driver monolithic active matrix circuit substrate 5, a counter electrode (not shown) provided so as to face the pixel electrode 79, and the pixel electrode 7
After applying a voltage to a capacitor called a liquid crystal capacitance formed by 9 and the liquid crystal sandwiched between the counter electrodes, the liquid crystal is driven by holding the voltage.
In order to hold the voltage sufficiently long, a capacitor called an auxiliary capacitor for auxiliary holding the voltage is provided in parallel with the liquid crystal capacitor. The auxiliary capacitance electrode 69 is an electrode for forming this auxiliary capacitance.

On the lower layer side of the semiconductor layer 80 of the display section 52, a lower layer light shielding film 62 is formed via a first interlayer insulating film 63. The lower light-shielding film 62 is disclosed in JP-A-11-843.
As disclosed in Japanese Patent No. 59, the pixel TFT 82
Light incident from below with respect to, for example, the transparent substrate 6
It is provided to block the reflected light from 1 and the like. By providing the lower light-shielding film 62, the light incident on the pixel TFT 82 from below can be reduced, so that the off current does not increase and the display quality of the liquid crystal display device deteriorates as described above. Can be prevented.

The lower light shielding film 62 and the upper light shielding film 76 are
It is not provided in the peripheral drive circuit section 51. TF for pixels
Unlike T82, since it is not necessary to directly illuminate the peripheral drive circuit TFT 81, the peripheral drive circuit TFT 81
Is shielded from light by a package or the like provided outside the driver monolithic active matrix circuit board 5. Therefore, in the peripheral drive circuit unit 51, the lower layer light shielding film 62 and the upper layer light shielding film 7 provided in the display unit 52 are provided.
A member for shielding light from the inside such as 6 is not necessary.

The transistor for the peripheral drive circuit is an element for performing high-speed calculation of liquid crystal display data input from the outside of the liquid crystal display device, converting it into a signal for input to the display portion, and inputting the signal to the display portion. . Since the peripheral drive circuit needs a complicated circuit and various response characteristics to drive the liquid crystal display device, the peripheral drive circuit transistor has a high carrier mobility (hereinafter, simply referred to as “mobility”). Also referred to as), high performance such as high speed operation and high ON characteristics is required.

The mobility of the peripheral drive circuit TFT of the driver monolithic type liquid crystal display device which has been practically used is
In the case of using poly-Si in the active region, N-type having conduction electrons as carriers and P-type having holes as carriers
It is about 100 cm ² / V · s in any TFT of the mold.

[0013]

However, the driving method of the peripheral drive circuit is improved to improve the display quality of the liquid crystal display device, or the area occupied by the peripheral drive circuit is reduced to downsize the liquid crystal display device. In order to do so, it is required to further improve the performance of the peripheral drive circuit transistor.

An object of the present invention is to provide a semiconductor device having a high-performance peripheral drive circuit transistor and a method for manufacturing the same.

[0015]

According to the present invention, there is provided, on a substrate, a display section including a plurality of pixel electrodes arranged in a matrix and a plurality of pixel transistors connected to the respective pixel electrodes, and a display section of the display section. A semiconductor device having a peripheral drive circuit portion which is provided in the periphery and includes a peripheral drive circuit transistor, wherein the peripheral drive circuit transistor is provided on an upper layer side of a channel region formed of a semiconductor layer with an insulating film interposed therebetween. A gate electrode is formed by stacking conductive layers,
In the peripheral drive circuit unit, a conductive film is provided below the semiconductor layer via an insulating film, and the conductive film provided below the semiconductor layer is electrically connected to the gate electrode. It is a semiconductor device characterized by the above.

According to the present invention, a semiconductor device includes a display section including a plurality of pixel electrodes arranged in a matrix and a plurality of pixel transistors connected to the respective pixel electrodes on a substrate, and the display section. And a peripheral drive circuit portion including a peripheral drive circuit transistor provided in the periphery, wherein the peripheral drive circuit transistor has a conductive layer on an upper layer side of a channel region formed of a semiconductor layer via an insulating film. A conductive film is provided on the lower layer side of the semiconductor layer via an insulating film in the peripheral drive circuit portion, the conductive film being provided on the lower layer side of the semiconductor layer. , Electrically connected to the gate electrode. This allows the conductive film provided on the lower layer side of the semiconductor layer and the gate electrode to have the same potential,
The conductive film provided on the lower layer side of the semiconductor layer can be used as a second gate electrode for controlling a current flowing through the peripheral drive circuit transistor, and the peripheral drive circuit transistor can have a double gate structure. That is, of the channel region, in addition to the vicinity of the surface facing the gate electrode, the vicinity of the surface facing the conductive film is used as a region through which a current passes when the peripheral drive circuit transistor is turned on. Therefore, high mobility and high on-state characteristics can be imparted to the peripheral driver circuit transistor provided in the semiconductor device, so that the peripheral driver circuit transistor can have high performance. Therefore,
Since the liquid crystal display device can be downsized by reducing the peripheral drive circuit section and the display quality of the liquid crystal display device can be improved by improving the driving method of the peripheral drive circuit, a highly functional driver monolithic active matrix liquid crystal display device,
In particular, it is possible to realize a liquid crystal display device for a projection device with high brightness and high definition, and to downsize and improve the performance of the projection device.

According to the present invention, the pixel transistor includes a gate electrode formed by laminating a conductive layer on an upper layer side of a channel region formed of a semiconductor layer with an insulating film interposed therebetween, and the display section is provided. On the lower layer side of the semiconductor layer,
A light-shielding conductive film is provided through an insulating film, and the conductive film provided in the peripheral drive circuit portion is a light-shielding conductive film, and is formed at the same time as the light-shielding conductive film provided in the display portion. And

According to the invention, the pixel transistor includes a gate electrode formed by laminating a conductive layer on an upper layer side of a channel region formed of a semiconductor layer with an insulating film interposed therebetween, Part, on the lower layer side of the semiconductor layer,
A light-shielding conductive film is provided through an insulating film, and the conductive film provided in the peripheral driver circuit portion is a light-shielding conductive film and is formed at the same time as the light-shielding conductive film provided in the display portion. As a result, the conductive film can be provided in the peripheral drive circuit section and the performance of the peripheral drive circuit transistor can be improved without increasing the number of manufacturing steps. Therefore, a peripheral drive circuit transistor having high mobility and high ON characteristics is formed in the peripheral drive circuit section, and a current flowing through the pixel transistor is formed in the display section when the pixel transistor is in an OFF state. It is possible to form a pixel transistor in which a certain off current is less likely to be increased by light.

Further, the invention is characterized in that the light-shielding conductive film provided in the display section is not electrically connected to the gate electrode of the pixel transistor.

According to the present invention, since the light-shielding conductive film provided in the display section is not electrically connected to the gate electrode of the pixel transistor, the light-shielding conductive film provided in the display section and the pixel The gate electrode of the transistor can have a different potential. When the light-shielding conductive film provided in the display portion and the gate electrode of the pixel transistor are electrically connected to have the same potential, the off current increases in the off state of the pixel transistor, and the pixel transistor It becomes difficult to hold the potential of the pixel electrode given by Therefore, as described above, the potential of the pixel electrode when the pixel transistor is off is lowered by setting the light-shielding conductive film provided in the display section and the gate electrode of the pixel transistor to different potentials. Can be prevented, and the display quality of a liquid crystal display device using such a semiconductor device can be improved.

According to the present invention, the film thickness d1 of the insulating film provided between the channel region of the peripheral drive circuit transistor and the conductive film of the peripheral drive circuit section is the same as the channel region of the pixel transistor and the display. Thinner than the film thickness d2 of the insulating film provided between the light-shielding conductive film of the other part (d1 <
d2).

According to the present invention, the film thickness d1 of the insulating film provided between the channel region of the peripheral drive circuit transistor and the conductive film of the peripheral drive circuit section is the same as that of the channel region of the pixel transistor. It is thinner than the film thickness d2 of the insulating film provided between the display portion and the light-shielding conductive film (d1
<D2). Since the strength of the electric field is inversely proportional to the square of the distance,
The closer the conductive film of the peripheral drive circuit portion used as the second gate electrode is to the channel region of the peripheral drive circuit transistor, the closer the conductive film of the peripheral drive circuit portion is to the peripheral drive circuit transistor. The strength of the electric field applied to the channel region increases. When the strength of the electric field applied to the channel region of the peripheral drive circuit transistor from the conductive film of the peripheral drive circuit unit is high, the current flowing through the channel region of the peripheral drive circuit transistor is changed to the peripheral drive circuit transistor. Since it increases / decreases with good response to ON / OFF switching, the effect of the conductive film of the peripheral drive circuit section as a gate electrode is enhanced. On the other hand, since the light-shielding conductive film of the display unit has conductivity, if the distance between the light-shielding conductive film of the display unit and the channel region of the pixel transistor is too short, the light-shielding conductive film of the display unit becomes Parasitic capacitance may occur between the pixel transistor and the semiconductor layer. When a parasitic capacitance is generated between the light-shielding conductive film of the display section and the semiconductor layer of the pixel transistor, the off current increases in the off state of the pixel transistor, and the pixel provided by the pixel transistor is increased. It becomes difficult to maintain the potential of the electrodes. Therefore, as described above, the film thickness d1 of the insulating film provided between the channel region of the peripheral drive circuit transistor and the conductive film of the peripheral drive circuit unit is set to the channel region of the pixel transistor and the display unit. By making the film thickness smaller than the film thickness d2 of the insulating film provided between the film and the light-shielding conductive film (d1 <d2), the effect of the conductive film of the peripheral drive circuit section as the gate electrode is enhanced, and
It is possible to prevent the generation of parasitic capacitance between the light-shielding conductive film of the display section and the semiconductor layer of the pixel transistor, and prevent the potential of the pixel electrode from decreasing when the pixel transistor is off.

According to the present invention, the conductive film of the peripheral drive circuit portion is provided so as to correspond to the channel region of the peripheral drive circuit transistor, and the channel region is formed on the surface of the conductive film facing the channel region. When projected, the projection image of the channel region is provided so as to be included in the surface of the conductive film.

According to the invention, the conductive film of the peripheral drive circuit portion is provided so as to correspond to the channel region of the peripheral drive circuit transistor, and the channel region is formed on the surface of the conductive film facing the channel region. When projecting
It is provided such that the projected image of the channel region is included in the surface of the conductive film. As a result, the conductive film of the peripheral drive circuit portion used as the second gate electrode can apply an electric field to all regions of the channel region of the peripheral drive circuit transistor. The effect of the conductive film of the drive circuit portion as the gate electrode can be enhanced.

According to the present invention, the semiconductor layer of the peripheral drive circuit transistor includes the channel region, an impurity-doped source region and a drain region which are formed on both sides of the channel region and extend along the channel region, and a channel. A low-concentration impurity region formed between the region and the source region and between the channel region and the drain region and having a lower concentration of impurities than the source region and the drain region. The film is provided so as to correspond to the channel region of the peripheral drive circuit transistor, and when the channel region and the low-concentration impurity region are projected onto the surface of the conductive film facing the channel region,
The projection image of the channel region and at least the end portion of the low-concentration impurity region near the channel region is provided so as to be included in the surface of the conductive film.

According to the present invention, the semiconductor layer of the transistor for peripheral drive circuit includes the channel region, and source and drain regions formed on both sides of the channel region and extending along the channel region. A low-concentration impurity region formed between the channel region and the source region and between the channel region and the drain region and having a lower concentration of impurities than the source region and the drain region. The conductive film is provided so as to correspond to the channel region of the peripheral drive circuit transistor, and when the channel region and the low concentration impurity region are projected onto the surface of the conductive film facing the channel region, at least the channel region and the low concentration impurity region are projected. Provided so that the projected image of the end portion of the low-concentration impurity region near the channel region is included in the surface of the conductive film. It is. As a result, as shown in FIGS. 10 and 11, which will be described later, a low-concentration impurity region is arranged at a position facing the end of the conductive film of the peripheral drive circuit section. When a voltage is applied to the conductive film of the peripheral drive circuit section to use as a second gate electrode,
The electric field at the end of the conductive film of the peripheral drive circuit section is stronger than the other areas. When this strong electric field is applied to the source region and the drain region of the peripheral drive circuit transistor having high conductivity, hot carriers which are carriers having high energy are generated and the characteristics as the peripheral drive circuit transistor are deteriorated. Though
When a strong electric field is applied to the low-concentration impurity region having low conductivity, generation of hot carriers is suppressed as compared with the case where the strong electric field is applied to the source region and the drain region.
Therefore, as described above, the semiconductor layer of the peripheral drive circuit transistor is provided with the channel region, the source region, the drain region, and the low-concentration impurity region, and the conductive film of the peripheral drive circuit portion is provided for the peripheral drive circuit. When projecting the channel region and the low-concentration impurity region so as to correspond to the channel region of the transistor and on the surface of the conductive film facing the channel region, the channel region and at least the end portion of the low-concentration impurity region near the channel region are By providing the projected image so as to be included on the surface of the conductive film,
It is possible to suppress the deterioration of the characteristics of the peripheral drive circuit transistor with time.

Further, according to the present invention, a display portion including a plurality of pixel electrodes arranged in a matrix and a plurality of pixel transistors connected to each pixel electrode on a substrate, and a peripheral portion provided around the display portion. A method of manufacturing a semiconductor device having a peripheral drive circuit section including a drive circuit transistor, the method comprising: forming a light-shielding conductive film on a substrate; and forming an insulating film on the light-shielding conductive film. A step of sequentially stacking a semiconductor layer to be a channel region, an insulating film, and a conductive layer to be a gate electrode on the insulating film; and a portion of the light-shielding conductive film that is predetermined to be the peripheral drive circuit section. A method of manufacturing a semiconductor device, comprising the step of electrically connecting a film and the gate electrode.

According to the present invention, a display portion including a plurality of pixel electrodes arranged in a matrix and a plurality of pixel transistors connected to each pixel electrode on a substrate, and provided around the display portion. A semiconductor device having a peripheral drive circuit section including a peripheral drive circuit transistor includes: a step of forming a light-shielding conductive film on a substrate; a step of forming an insulating film on the light-shielding conductive film; A step of sequentially stacking a semiconductor layer to be a channel region, an insulating film, and a conductive layer to be a gate electrode on the film; and a portion of the light-shielding conductive film and the gate to be the peripheral drive circuit portion which is predetermined. It is manufactured through a process of electrically connecting with an electrode. As a result, the light-shielding conductive film provided in the peripheral drive circuit portion and electrically connected to the gate electrode is used to reduce the light incident on the pixel transistor and suppress the increase in off current. Can be formed at the same time as the light-shielding conductive film provided in the portion. Further, since the light-shielding conductive film provided in the peripheral drive circuit section and the gate electrode of the peripheral drive circuit transistor can have the same potential, the light-shielding conductive film provided in the peripheral drive circuit section is The peripheral drive circuit transistor may have a double gate structure by being used as a second gate electrode for controlling a current flowing through the peripheral drive circuit transistor. That is, in the channel region of the transistor for peripheral drive circuit, in addition to the vicinity of the surface facing the gate electrode, the vicinity of the surface facing the light-shielding conductive film,
Since it can be used as a region through which a current passes when the peripheral drive circuit transistor is turned on, the peripheral drive circuit transistor provided in the semiconductor device is provided with high mobility and high on-characteristics, and high performance is obtained. Can be used as a transistor for the peripheral drive circuit. Therefore, a semiconductor device having a high-performance peripheral drive circuit transistor can be manufactured without increasing the number of steps.

Further, in the present invention, the step of forming an insulating film on the light-shielding conductive film, the step of forming a lower insulating film on the light-shielding conductive film, and the peripheral drive circuit portion are predetermined to be the peripheral drive circuit portion. The method is characterized by including a step of removing the lower layer insulating film in a desired portion by etching, and a step of forming an upper layer insulating film on the surface of the substrate after the etching.

According to the invention, on the light-shielding conductive film,
The step of forming an insulating film includes a step of forming a lower layer insulating film on the light-shielding conductive film, a step of removing the lower layer insulating film in a predetermined portion to be the peripheral drive circuit section by etching, Forming an upper insulating film on the surface of the substrate after etching. As a result, it is provided between the channel region of the peripheral drive circuit transistor and the light-shielding conductive film of the peripheral drive circuit section, and between the channel region of the pixel transistor and the light-shielding conductive film of the display section. An insulating film having a film thickness d1 (d1 <d2) smaller than the film thickness d2 of the obtained insulating film can be provided.
Since the strength of the electric field is inversely proportional to the square of the distance, the shorter the distance between the light-shielding conductive film of the peripheral drive circuit section used as the second gate electrode and the channel region of the peripheral drive circuit transistor, the more The strength of the electric field applied to the channel region of the peripheral drive circuit transistor by the light-shielding conductive film of the peripheral drive circuit portion is increased. When the strength of the electric field applied from the light-shielding conductive film of the peripheral drive circuit section to the channel region of the peripheral drive circuit transistor is high, the current flowing through the channel region of the peripheral drive circuit transistor is changed to the peripheral drive circuit. Since the response transistor increases / decreases with good response to ON / OFF switching, the effect as the gate electrode of the light-shielding conductive film of the peripheral drive circuit section is enhanced. On the other hand, since the light-shielding conductive film of the display unit has conductivity, if the distance between the light-shielding conductive film of the display unit and the channel region of the pixel transistor is too short, the light-shielding conductive film of the display unit becomes Parasitic capacitance may occur between the pixel transistor and the semiconductor layer. When a parasitic capacitance is generated between the light-shielding conductive film of the display section and the semiconductor layer of the pixel transistor, the off current increases in the off state of the pixel transistor, and the pixel provided by the pixel transistor is increased. It becomes difficult to maintain the potential of the electrodes. Therefore, as mentioned above,
An insulating film provided between the channel region of the peripheral drive circuit transistor and the light-shielding conductive film of the peripheral drive circuit section, and between the channel region of the pixel transistor and the light-shielding conductive film of the display section. Film thickness d smaller than film thickness d2
By providing the insulating film of 1 (d1 <d2), the effect as the gate electrode of the light-shielding conductive film of the peripheral drive circuit section is enhanced, and the light-shielding conductive film of the display section and the semiconductor layer of the pixel transistor are provided. It is possible to prevent the generation of parasitic capacitance between the pixel electrode and the pixel electrode, and to prevent the potential of the pixel electrode from decreasing when the pixel transistor is off.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A driver monolithic active matrix circuit board 1 will be illustrated as a semiconductor device according to a first embodiment of the present invention. FIG. 1 is a sectional view showing a schematic configuration of a driver monolithic active matrix circuit board 1. In FIG. 1, a plurality of pixel electrodes 39 arranged in a matrix and each pixel electrode 3 are arranged.
9, a plurality of pixel thin film transistors (TF)
T) 42 and a part of the display section 12 and a part of the peripheral drive circuit section 11 provided around the display section 12 and including the peripheral drive circuit TFT 41. Also, TFTs for peripheral drive circuits
41 is a field effect transistor (Metal-Oxide-SemiconductorField E) having a metal-oxide-semiconductor structure.
f-type transistor (abbreviation: MOS FET), N-type MOS FET whose carrier is a conduction electron (hereinafter,
"NMOS").

As shown in FIG. 1, in the driver monolithic active matrix circuit substrate 1, a peripheral drive circuit TFT 41 and a pixel TFT 42 are formed on a quartz substrate 21 via a first interlayer insulating film 24. Has been done. Peripheral drive circuit TFT 41 and pixel TFT 42
Is on the upper side of the channel region 29a, the source region 29b and the drain region 29c formed of the semiconductor layer 25,
A gate electrode 28 formed by stacking conductive layers is provided via a second interlayer insulating film 26. On the upper layer side of the gate electrode 28, the source electrode 33 electrically connected to the source region 29b by the source electrode contact hole 31 via the third interlayer insulating film 30, and the drain region 29c by the drain electrode contact hole 32. A drain electrode 34 electrically connected to the drain electrode 34 is formed. In the display section 12, the upper light-shielding film 36 is provided on the upper layer side of the source electrode 33 and the drain electrode 34 with the fourth interlayer insulating film 35 interposed therebetween.
And a pixel electrode contact hole 38 on the upper layer side of the upper layer light-shielding film 36 with a fifth interlayer insulating film 37 interposed.
The drain electrode 3 is formed by the conductive film 40 formed on the surface of the
The pixel electrode 39 electrically connected to the pixel electrode 4 is formed. Here, the surface of the pixel electrode contact hole 38 is the surface of the fourth interlayer insulating film 35 and the fifth interlayer insulating film 37 facing the pixel electrode contact hole 38. Further, the display portion 12 is formed with an auxiliary capacitance electrode 28a. On the lower layer side of the semiconductor layer 25, the lower conductive film 23 is formed in the peripheral drive circuit section 11 via the first interlayer insulating film 24, and the lower light shielding film 22 which is a light shielding conductive film is formed in the display section 12. Has been formed.

FIG. 2A shows a state in which the gate electrodes 28 are formed in the peripheral drive circuit portion 11 of the driver monolithic active matrix circuit substrate 1 shown in FIG.
It is a figure shown planarly from the direction of arrow 13. Note that FIG.
In (a), the description of the first interlayer insulating film 24 and the second interlayer insulating film 26 is omitted because the figures are complicated and the understanding is difficult. 2B is a cross-sectional view showing a cross-sectional structure taken along the section line I-I 'of the peripheral drive circuit section 11 shown in FIG.

As shown in FIG. 2B, the lower conductive film 23.
Are electrically connected to the gate electrode 28 of the peripheral drive circuit TFT 41 through the gate electrode contact hole 27. This allows the lower conductive film 23 and the gate electrode 28 of the peripheral drive circuit TFT 41 to have the same potential, so that the lower conductive film 23 can be connected to the peripheral drive circuit T.
The peripheral drive circuit TFT 41 can be made to have a double gate structure by using it as a second gate electrode for controlling the current flowing through the FT 41.

On the other hand, in the peripheral drive circuit TFT 81 of the driver monolithic active matrix circuit substrate 5 shown in FIG. 14, the gate electrode is the gate electrode 68.
Only. An element called a TFT is turned on / off by applying a voltage to a gate electrode to generate an electric field and controlling the flow of a current passing through a channel region between a source region and a drain region by the effect of the generated electric field. Is an element that performs switching. In the case of the driver monolithic active matrix circuit substrate 5 shown in FIG. 14 described above, when a voltage is applied to the gate electrode 68 to turn on the peripheral drive circuit TFT 81, the peripheral drive circuit TFT 81 passes through the channel region 65. Most of the on-current, which is a current, passes through a portion having a depth of about several nm from the interface between the channel region 65 and the gate insulating film 67, that is, near the surface of the channel region 65 facing the gate electrode 68. Therefore, a portion of the channel region 65 that is far away from the interface between the channel region 65 and the gate insulating film 67, that is, the vicinity of the surface of the channel region 65 facing the transparent substrate 61 does not contribute much to the on-current.

In the driver monolithic active matrix circuit substrate 1 according to this embodiment, as described above, the lower conductive film 23 is electrically connected to the gate electrode 28, and the peripheral drive circuit TFT 41 has a double gate structure. Therefore, in the channel region 29a, in addition to the vicinity of the surface facing the gate electrode 28, the vicinity of the surface facing the lower conductive film 23 is used as a region through which a current passes when the peripheral drive circuit TFT 41 is turned on. Therefore, high mobility and high on-characteristics are imparted to the peripheral drive circuit TFT 41, and the peripheral drive circuit TFT 41 with high performance is provided.
It can be 41. Therefore, it is possible to reduce the size of the peripheral drive circuit portion provided in the semiconductor device and improve the drive system of the peripheral drive circuit. By using such a semiconductor device, the liquid crystal display device can be downsized and the display quality can be improved. Therefore, a high-performance driver monolithic active matrix liquid crystal display device, particularly a liquid crystal for a high-luminance and high-definition projection device. Realization of display device,
It is possible to reduce the size and performance of the projection device.

As shown in FIG. 1, the lower conductive film 23 is provided so as to correspond to the channel region 29a of the peripheral drive circuit TFT 41, and the channel region is formed on the surface 23a of the lower conductive film 23 facing the channel region 29a. When projecting 29 a, the projected image of the channel region 29 a is included in the surface 23 a of the lower conductive film 23. As a result, as described above, the lower conductive film 23 used as the second gate electrode can apply an electric field to all the regions of the channel region 29a of the peripheral drive circuit TFT 41, so that the lower conductive film is formed. The effect of the film 23 as a gate electrode can be enhanced.

The lower conductive film 23 is a light-shielding conductive film and is formed simultaneously with the lower light-shielding film 22 of the display section 12.
As a result, the lower conductive film 23 can be provided in the peripheral drive circuit section 11 and the performance of the peripheral drive circuit TFT 41 can be improved without increasing the number of manufacturing steps. Therefore, the peripheral drive circuit section 11 is formed with the peripheral drive circuit TFT 41 having high mobility and high on-characteristics, and the display section 12 is formed with the pixel TFT 42 in which the off current hardly increases due to light. be able to.

The lower light-shielding film 22 is formed by the pixel TFT 42.
Therefore, the lower light-shielding film 22 and the gate electrode 28 of the pixel TFT 42 can have different potentials. In the pixel TFT 42, unlike the peripheral drive circuit TFT 41, it is necessary to prevent the potential of the pixel electrode 39 from decreasing when the pixel TFT 42 is off. Therefore, the low off current characteristic is most important. Lower light-shielding film 22
When the gate electrode 28 of the pixel TFT 42 and the gate electrode 28 of the pixel TFT 42 are electrically connected to each other and have the same potential, the OFF current increases in the OFF state of the pixel TFT 42, and the potential of the pixel electrode 39 provided by the pixel TFT 42 is held. Becomes difficult. Therefore, as described above, by setting the lower light-shielding film 22 and the gate electrode 28 of the pixel TFT 42 at different potentials, it is possible to prevent the potential of the pixel electrode 39 from decreasing when the pixel TFT 42 is off. The display quality of a liquid crystal display device using such a semiconductor device can be improved. Since the lower light-shielding film 22 has conductivity,
A parasitic capacitance may be generated between the lower light-shielding film 22 and the semiconductor layer 25 of the pixel TFT 42, and the off current may increase. In order to prevent the generation of parasitic capacitance, the lower light shielding film 22
It is preferable that the gate electrode 28 of the pixel TFT 42 and the gate electrode 28 have different potentials.

From the above, the lower conductive film 23, which is the light-shielding conductive film of the peripheral drive circuit section 11, is formed by the TF for the peripheral drive circuit.
The potential is the same as that of the gate electrode 28 of T41, and the lower light-shielding film 22 which is a light-shielding conductive film of the display unit 12 is the pixel TFT 42.
It is particularly preferable that the potential is different from that of the gate electrode 28.

A method of manufacturing the driver monolithic active matrix circuit board 1 shown in FIG. 1 will be described.
3 to 9 are diagrams schematically showing states of respective steps in manufacturing the driver monolithic active matrix circuit board 1. 3 to 5 and 7 to 9 are cross-sectional views showing a part of the peripheral drive circuit section 11 and a part of the display section 12, similarly to FIG.

FIG. 3 shows the lower light-shielding film 2 on the quartz substrate 21.
2 is a diagram showing a state in which a lower conductive film 23 and a first interlayer insulating film 24 are formed. First, for example, a poly-Si film having a film thickness of about 50 nm and a film thickness of 1 are formed on the quartz substrate 21.
About 100 nm tungsten silicide (chemical formula: WSi)
The film is continuously formed, and the conductive light-shielding film WSi / poly
Form a two-layer film of Si. Formed WSi / poly-S
By patterning the i two-layer film by photolithography and dry etching, the lower conductive film 23 of the peripheral drive circuit unit 11 and the lower light shielding film 22 of the display unit 12 are formed.
To form.

As described above, as described above, the T for the peripheral drive circuit is provided in the peripheral drive circuit section 11.
The lower conductive film 23 electrically connected to the gate electrode 28 of the FT 41 is formed at the same time as the lower light shielding film 22 provided in the display unit 12 in order to reduce the light incident on the pixel TFT 42 and suppress the increase of the off current. be able to. Therefore, the driver monolithic active matrix circuit board 1 having the high-performance peripheral drive circuit TFT 41 can be manufactured without increasing the number of steps.

Next, a silicon dioxide (chemical formula: SiO ₂ ) film, for example, having a film thickness A of 380 n is formed on the entire surface of the quartz substrate 21 on which the lower light-shielding film 22 and the lower conductive film 23 are formed.
The first interlayer insulating film 24 is formed by forming a film having a thickness of about m. The lower conductive film 23 of the peripheral drive circuit section 11 is applied with the same voltage as the gate electrode 28 as described above and is used as the second gate electrode. Serves as a gate insulating film for the lower conductive film 23.

FIG. 4 is a diagram showing a state in which the semiconductor layer 25 and the second interlayer insulating film 26 are formed on the first interlayer insulating film 24. On the first interlayer insulating film 24, for example,
The semiconductor layer 25 is formed by forming an amorphous Si film so as to have a film thickness of about 60 nm and crystallizing the amorphous Si film into a crystalline Si film. This amorphous S
As a method of crystallizing the i film, there can be used a method of growing a crystal at a temperature of about 600 ° C., a method of melting by irradiation with an excimer laser, and a method of crystallizing. The formed semiconductor layer 25 is patterned into a predetermined shape by photolithography and dry etching.

A SiO ₂ film having a film thickness of 60 is formed on the entire surface of the quartz substrate 21 after the patterning of the semiconductor layer 25.
After being formed to have a thickness of about 10 nm, the semiconductor layer 25 made of a crystalline Si film is partially oxidized by heating at 950 ° C. in an atmosphere containing oxygen atoms, and the semiconductor layer of the SiO ₂ film previously formed is formed. By increasing the film thickness on 25 to about 80 nm, the second interlayer insulating film 26 with the film thickness B on the semiconductor layer 25 being about 80 nm is formed. This oxidation treatment can reduce defects inside the semiconductor layer 25 and the second interlayer insulating film 26, and can improve the state of the interface between the semiconductor layer 25 and the second interlayer insulating film 26. The peripheral drive circuit TFT 41 and the pixel TFT 42 having high reliability, high mobility, and high on-characteristics can be formed.

FIG. 5 shows the gate electrode contact hole 2
7, gate electrode 28, auxiliary capacitance electrode 28a, channel region 29a, source region 29b and drain region 29c
It is a figure which shows the state which formed. In order to form a region electrically connected to the auxiliary capacitance electrode 28a to the semiconductor layer 25 of the display section 12 and applying a potential to the auxiliary capacitance electrode 28a, at least the channel region 29a of the semiconductor layer 25 is previously formed by photolithography. After covering the predetermined portion of the second interlayer insulating film 26 with a resist, pentavalent impurities serving as a source of conduction electrons, for example, 2 × 10 ¹⁵ atoms, are provided in predetermined portions to be the source region 29b and the drain region 29c. Phosphorus ions of about / cm ² are implanted. In the display unit 12, the region where the phosphorus ions are implanted is
It will later become a part of the drain region 29c, and will become the auxiliary capacitance electrode 2
It is electrically connected to 8a and functions as a region for applying a potential to the auxiliary capacitance electrode 28a.

FIG. 6A is a plan view showing a state in which the gate electrode contact hole 27 is formed in the peripheral drive circuit section 11 as viewed in the direction of arrow 14 in FIG. In addition,
In FIG. 6A, the first interlayer insulating film 24 and the second
The description of the interlayer insulating film 26 is omitted because the figure is complicated and it is difficult to understand. FIG. 6B is a cross-sectional view showing a cross-sectional structure taken along the section line II-II ′ of the peripheral drive circuit section 11 shown in FIG. As shown in FIG. 6B, portions of the first interlayer insulating film 24 and the second interlayer insulating film 2 which are predetermined to be the gate electrode contact holes 27 by photolithography and dry etching are formed.
By removing 6, the gate electrode contact hole 27 reaching the lower conductive film 23 is formed in the peripheral drive circuit portion 11 to expose a part of the lower conductive film 23. This etching does not remove the first interlayer insulating film 24 and the second interlayer insulating film 26 of the display section 12.

On the surface of the quartz substrate 21 after etching, for example, a poly-Si film having a film thickness of about 50 nm and a film thickness of 1 are formed.
A WSi film of about 00 nm is continuously formed to form a WSi / poly-Si two-layer film which is a conductive layer. W formed
The Si / poly-Si bilayer film is patterned by photolithography and dry etching to form the gate electrode 28 and the auxiliary capacitance electrode 28a. At this time, the inside of the gate electrode contact hole 27 of the peripheral drive circuit section 11 was filled with the conductive materials WSi and poly-Si as shown in FIG. 2B, and was filled with this conductive material. The gate electrode 28 and the lower conductive film 23 are electrically connected by the gate electrode contact hole 27. Therefore, the peripheral drive circuit unit 11
Since the lower conductive film 23 and the gate electrode 28 of the peripheral drive circuit TFT 41 can have the same potential, as described above, the lower conductive film 23 is used as the second gate electrode and the peripheral drive circuit TFT 41 is used. Can have a double-gate structure having upper and lower gate electrodes. On the other hand, in the display unit 12, as described above, in order to reduce the leakage current in the off state of the pixel TFT 42, the lower light shielding film 22 is formed.
Since it is preferable that the gate electrode 28 and the gate electrode 28 have different potentials, the lower light-shielding film 22 and the gate electrode 28 are not electrically connected.

Gate electrode 28 and auxiliary capacitance electrode 28a
With the mask as a mask, pentavalent impurities serving as a supply source of conduction electrons, for example, phosphorus ions of about 2 × 10 ¹⁵ atoms / cm ² are implanted into the semiconductor layer 25. As a result, a channel region 29a not doped with impurities, and a source region 29b and a drain region 29c doped with impurities are formed.

FIG. 7 is a diagram showing a state in which the third interlayer insulating film 30, the source electrode contact hole 31, and the drain electrode contact hole 32 are formed. Channel region 29a, source region 29b and drain region 29c
S is formed on the entire surface of the quartz substrate 21 after the formation of S.
A third interlayer insulating film 30 is formed by forming an iO ₂ film so that the film thickness C becomes about 600 nm. The source electrode contact hole 31 and the drain electrode contact hole 32 are provided with a second portion that is predetermined.
By removing the interlayer insulating film 26 and the third interlayer insulating film 30, the source electrode contact hole 31 reaching the source region 29b and the drain electrode contact hole 32 reaching the drain region 29c are formed.

FIG. 8 shows the source electrode 33 and the drain electrode 3
FIG. 6 is a diagram showing a state in which the fourth and fourth interlayer insulating films 35 are formed. Quartz substrate 2 after formation of source electrode contact hole 31 and drain electrode contact hole 32
For example, titanium (element symbol: Ti)
-Tungsten (element symbol: W) alloy (hereinafter "Ti
Abbreviated as "W") film, aluminum (elemental symbol: Al)
-By continuously forming three layers of a silicon alloy (hereinafter abbreviated as "AlSi") film and a TiW film,
A three-layer film of TiW / AlSi / TiW is formed. The source electrode 33 and the drain electrode 34 are formed by patterning the formed TiW / AlSi / TiW three-layer film by photolithography and dry etching. At this time, the source electrode contact hole 31
The inside of the drain electrode contact hole 32 is filled with TiW and AlSi which are conductive materials. The source electrode 33, the source region 29b, and the drain electrode 34 are formed by the source electrode contact hole 31 and the drain electrode contact hole 32 filled with the conductive material.
And the drain region 29c are electrically connected to each other.

The fourth interlayer insulating film is formed by forming, for example, a silicon nitride film on the entire surface of the quartz substrate 21 after the source electrode 33 and the drain electrode 34 are formed so that the film thickness D is about 200 nm. 35 is formed.
Then, heat treatment is performed at 950 ° C. for 30 minutes. This heat treatment is for activating phosphorus ions, which are impurities contained in the source region 29b and the drain region 29c,
This is performed in order to improve the film quality by introducing hydrogen atoms into the semiconductor layer 25 made of a crystalline Si film.

FIG. 9 is a diagram showing a state in which the upper light-shielding film 36, the fifth interlayer insulating film 37, the pixel electrode contact hole 38 and the pixel electrode 39 are formed. A TiW film, for example, is formed on the fourth interlayer insulating film 35 so as to have a film thickness of about 150 nm and then patterned,
The upper light-shielding film 36 is formed on the display unit 12. Upper light-shielding film 3
A fifth interlayer insulating film 37 is formed by forming, for example, a SiO ₂ film on the entire surface of the quartz substrate 21 after forming 6. The pixel electrode contact hole 38 reaching the drain electrode 34 of the pixel TFT 42 is formed by removing the portions of the fourth interlayer insulating film 35 and the fifth interlayer insulating film 37 which are predetermined to become the pixel electrode contact hole 38. A part of the drain electrode 34 of the pixel TFT 42 is exposed. For example, indium is formed on the entire surface of the fifth interlayer insulating film 37 and the surface of the pixel electrode contact hole 38, that is, the surfaces of the fourth interlayer insulating film 35 and the fifth interlayer insulating film 37 facing the pixel electrode contact hole 38. -Tin alloy oxide (Indium-Tin Oxid
e; Abbreviation: ITO) is deposited to form a light-transmitting conductive film 40, and then the pixel electrode 39 is formed by patterning using a photolithography method and dry etching. At this time, the conductive film 40 formed on the surface of the pixel electrode contact hole 38 also remains without being removed, and the conductive film 40 formed on the surface of the pixel electrode contact hole 38 causes the pixel electrode 39 and the drain electrode of the pixel TFT 42. 34 is electrically connected. The driver monolithic active matrix circuit board 1 is obtained as described above.

As a semiconductor device according to the second embodiment of the present invention, a driver monolithic active matrix circuit board 2 will be exemplified. FIG. 10 is a cross-sectional view showing a schematic configuration of the driver monolithic active matrix circuit board 2. 10, like FIG. 1, a part of the peripheral drive circuit unit 11 and a part of the display unit 12 are shown.
An NMOS is shown as the peripheral drive circuit TFT 41. FIG. 11A is a plan view showing a state in which the gate electrodes 28 are formed in the peripheral drive circuit section 11 of the driver monolithic active matrix circuit substrate 2 shown in FIG. Note that FIG.
In (a), the description of the first interlayer insulating film 24 and the second interlayer insulating film 26 is omitted because the figures are complicated and the understanding is difficult. 11B is a cross-sectional view showing a cross-sectional structure taken along the section line III-III ′ of the peripheral drive circuit section 11 shown in FIG. Driver Monolithic Active Matrix Circuit Board 2 of this Embodiment
Is similar to the driver monolithic type active matrix circuit board 1 of the first embodiment, and the corresponding parts are designated by the same reference numerals and the description thereof will be omitted.

It should be noted that the TFT 41 for the peripheral drive circuit
Of the semiconductor layer 125 between the channel region 29a, the source region 29b and the drain region 29c which are formed on both sides of the channel region 29a and which extend along the channel region 29a, and which are doped with impurities. And an LDD (Lightly Doped Drain) region 2 which is a low-concentration impurity region formed between the channel region 29a and the drain region 29c and having a lower concentration of impurities than the source region 29b and the drain region 29c.
9d and the peripheral drive circuit TFT 41 has an LDD structure. Further, the lower conductive film 23 of the peripheral drive circuit portion 11 is provided so as to correspond to the channel region 29a of the peripheral drive circuit TFT 41, and the channel region 29a and the LDD are formed on the surface 23a of the lower conductive film 23 facing the channel region 29a. When projecting the region 29d, the channel region 29a and at least the channel region 29a
The projected image of the end portion of the LDD region 29d nearer to the lower conductive film 2
3 is provided so as to be included in the surface 23a.

As a result, the LDD region 29d, which is a low-concentration impurity region, is arranged at a position facing the end of the lower conductive film 23 of the peripheral drive circuit section 11. As described above, by applying a voltage to the lower conductive film 23,
When it is used as a gate electrode of, the electric field at the end of the lower conductive film 23 is stronger than at other portions. When this strong electric field is applied to the highly conductive source region 29b and drain region 29c, hot carriers are generated,
Although the characteristics as the peripheral drive circuit TFT 41 deteriorate, when a strong electric field is applied to the LDD region 29d, which is a low-concentration impurity region having low conductivity, or when applied to the source region 29b and the drain region 29c described above. In comparison, generation of hot carriers is suppressed. Therefore, as described above, the lower conductive film 2 of the peripheral drive circuit unit 11 is formed.
LD which is a low concentration impurity region at a position facing the end of
By arranging the D region 29d, generation of hot carriers is suppressed, and the peripheral drive circuit TFT 4 is provided.
It is possible to suppress deterioration of the characteristics of No. 1 with time.

A method of manufacturing the driver monolithic active matrix circuit board 2 shown in FIG. 10 will be described. Since the method of manufacturing the driver monolithic active matrix circuit board 2 of the present embodiment is similar to the method of manufacturing the driver monolithic active matrix circuit board 1 of the first embodiment, description of similar steps will be omitted. Different steps, that is, steps of adding impurities and forming the gate electrode contact hole 27, the gate electrode 28, and the auxiliary capacitance electrode 28a shown in FIGS. 5 and 6 will be described below.

In the present embodiment, in the process of adding impurities and forming the gate electrode contact hole 27, the gate electrode 28 and the auxiliary capacitance electrode 28a shown in FIGS. When impurities are added to form a region that is electrically connected to the auxiliary capacitance electrode 28a and applies a potential to the auxiliary capacitance electrode 28a,
Channel regions 29 of the semiconductor layers 125 and 25
In addition to the portion predetermined as a, the second interlayer insulating film 26 in the portion predetermined as the LDD region 29d which is a low concentration impurity region is covered with a resist,
Impurities, such as 2 × 10 ¹⁵ atom, are added to predetermined portions to be the source region 29b and the drain region 29c.
Implant phosphorus ions at about s / cm ² . The predetermined portion to be the LDD region 29d is determined so that the LDD region 29d is arranged at a position facing the end of the lower conductive film 23 of the peripheral drive circuit section 11 used as the second gate electrode.

Then, similarly to the first embodiment, the gate electrode contact hole 27, the gate electrode 28 and the auxiliary capacitance electrode 28a are formed. Formed gate electrode 2
When the impurities are added to the semiconductor layer 125 and the semiconductor layer 25 by using the mask 8 and the auxiliary capacitance electrode 28a as a mask, the concentration of the impurity added to the source region 29b and the drain region 29c is lower than the concentration of the impurity added in advance. Add impurities. For example, as described above, when phosphorus ions of about 2 × 10 ¹⁵ atoms / cm ² are implanted into the predetermined regions to be the source region 29b and the drain region 29c, about 2 × 10 ¹³ atoms / cm ² Inject phosphorus ions. As a result, in addition to the impurity-doped channel region 29a, the impurity-doped source region 29b and the drain region 29c, the impurity concentration is lower than that of the source region 29b and the drain region 29c. L which is an impurity region
The DD region 29d is replaced with the channel region 29 of the semiconductor layer 125.
a between the source region 29b and the channel region 29a
And the drain region 29c.

The driver monolithic active matrix circuit substrate 2 having the peripheral drive circuit TFT 41 of the LDD structure is obtained in the same manner as in the first embodiment except for the steps described above.

As a semiconductor device according to the third embodiment of the present invention, a driver monolithic active matrix circuit board 3 will be exemplified. FIG. 12 is a sectional view showing a schematic configuration of the driver monolithic active matrix circuit board 3. 12, like FIG. 1, a part of the peripheral drive circuit section 11 and a part of the display section 12 are shown.
An NMOS is shown as the peripheral drive circuit TFT 41. The driver monolithic active matrix circuit board 3 of this embodiment is the same as the driver monolithic active matrix circuit board 1 of the first embodiment.
The same reference numerals are assigned to the corresponding portions and the description thereof will be omitted.

It should be noted that the first interlayer insulating film 124 provided between the channel region 29a of the pixel TFT 42 and the lower light-shielding film 22 which is the light-shielding conductive film of the display section 12 is the pixel lower-layer insulating film 124a. The thickness d1 of the first interlayer insulating film 124, which includes the upper insulating film 124b and is formed between the channel region 29a of the TFT 41 for peripheral drive circuit and the lower conductive film 23, is equal to the thickness T1 of the pixel T.
The pixel lower layer insulating film 124a and the pixel lower layer insulating film 124 provided between the channel region 29a of the FT 42 and the lower layer light shielding film 22.
That is, it is thinner (d1 <d2) than the thickness d2 of the first interlayer insulating film 124 formed by b.

Since the strength of the electric field is inversely proportional to the square of the distance, the distance between the lower conductive film 23 of the peripheral drive circuit section 11 used as the second gate electrode and the channel region 29a of the peripheral drive circuit TFT 41 is close. The lower conductive film 23
The electric field strength applied to the channel region 29a of the peripheral drive circuit TFT 41 becomes stronger. When the strength of the electric field applied from the lower conductive film 23 to the channel region 29a of the peripheral drive circuit TFT 41 is high, the current flowing through the channel region 29a of the peripheral drive circuit TFT 41 is changed to TF for the peripheral drive circuit.
Since the response increases / decreases with respect to ON / OFF switching of T41, the effect of the lower conductive film 23 as a gate electrode is enhanced. On the other hand, since the lower-layer light-shielding film 22 of the display section 12 has conductivity, if the distance between the lower-layer light-shielding film 22 and the channel region 29a of the pixel TFT 42 is too short, the lower-layer light-shielding film 22 and the semiconductor layer 25 of the pixel TFT 42 will be separated from each other. A parasitic capacitance may occur between the two. Lower light-shielding film 22 and pixel TF
When a parasitic capacitance is generated between the semiconductor layer 25 of T42,
In the off state of the pixel TFT 42, the off current increases, and the pixel electrode 39 provided by the pixel TFT 42
It becomes difficult to maintain the potential of.

Therefore, as described above, the film thickness d1 of the first interlayer insulating film 124 provided between the channel region 29a of the peripheral drive circuit TFT 41 and the lower conductive film 23.
Is made thinner than the film thickness d2 of the first interlayer insulating film 124 provided between the channel region 29a of the pixel TFT 42 and the lower light-shielding film 22 (d1 <d2). And the semiconductor layer 25 of the pixel TFT 42.
It is possible to prevent the generation of parasitic capacitance between the pixel electrode and the pixel electrode, and to prevent the potential of the pixel electrode 39 from decreasing when the pixel TFT 42 is off.

A method of manufacturing the driver monolithic active matrix circuit board 3 shown in FIG. 12 will be described. Since the method of manufacturing the driver monolithic active matrix circuit board 3 of the present embodiment is similar to the method of manufacturing the driver monolithic active matrix circuit board 1 of the first embodiment, description of similar steps is omitted. Different steps, that is, steps of forming the lower light-shielding film 22, the lower conductive film 23, and the first interlayer insulating film 24 shown in FIG. 3 will be described below.

In the present embodiment, first, similarly to the first embodiment, the lower layer light-shielding film 22 and the lower layer conductive film 23 which are light-shielding conductive films are formed. Next, in the first embodiment, the first interlayer insulating film 24 is formed on the entire surface of the quartz substrate 21 on which the lower light shielding film 22 and the lower conductive film 23 are formed, but in the present embodiment, the pixel lower insulating film 124a is formed.
And a first interlayer insulating film 124 including an upper insulating film 124b
To form.

The first interlayer insulating film 124 is formed as follows. First, for example, a SiO ₂ film is formed on the entire surface of the quartz substrate 21 after the lower light-shielding film 22 and the lower conductive film 23 are formed so that the film thickness d3 is about 280 nm. To form. Of the formed pixel lower layer insulating film 124a, a portion of the pixel lower layer insulating film 124a that is predetermined to become the peripheral drive circuit section 11 is removed by photolithography and dry etching. Then, for example, a SiO ₂ film is formed on the entire surface of the quartz substrate 21 after etching to a film thickness d1
By forming a film with a thickness of about 100 nm,
The upper insulating film 124b is formed. As a result, the pixel lower layer insulating film 124a and the upper layer insulating film 124b are formed, and the channel region 29a of the pixel TFT 42 and the lower layer light shielding film 22 are formed.
And the film thickness d2 between the pixel underlayer insulating film 124a
3 and the film thickness d1 of the upper insulating film 124b (d2 = d3
The first interlayer insulating film 124 of + d1) is formed.

As described above, the channel region 29a of the peripheral drive circuit TFT 41 and the lower conductive film 2 are formed.
3, the first interlayer insulating film 1 provided between the channel region 29a of the pixel TFT 42 and the lower light-shielding film 22.
The first interlayer insulating film 124 having a film thickness d1 (d1 <d2) smaller than the film thickness d2 of 24 can be provided.

The driver monolithic active matrix circuit board 3 is obtained in the same manner as in the first embodiment except the steps described above.

As a semiconductor device according to the fourth embodiment of the present invention, a driver monolithic active matrix circuit board 4 will be exemplified. FIG. 13 is a sectional view showing a schematic structure of the driver monolithic active matrix circuit board 4. Similar to FIG. 1, FIG. 13 shows a part of the peripheral drive circuit unit 11 and a part of the display unit 12.
An NMOS is shown as the peripheral drive circuit TFT 41. The driver monolithic active matrix circuit board 4 of this embodiment is the same as the driver monolithic active matrix circuit board 2 of the second embodiment.
And the driver monolithic active matrix circuit board 3 of the third embodiment are combined. Corresponding parts are designated by the same reference numerals and description thereof will be omitted.

In the driver monolithic active matrix circuit substrate 4 according to the present embodiment, the semiconductor layer 125 is a channel not doped with impurities, as in the driver monolithic active matrix circuit substrate 2 according to the second embodiment described above. Region 29a, and impurity-doped source region 29b and drain region 29
c and an LDD region 29d which is a low-concentration impurity region doped with an impurity at a lower concentration than the source region 29b and the drain region 29c, and faces the end of the lower conductive film 23 of the peripheral drive circuit unit 11. An LDD region 29d which is a low concentration impurity region is arranged at the position. As a result, the generation of hot carriers is suppressed and the T for the peripheral drive circuit is
It is possible to suppress deterioration of the characteristics of the FT 41 with time.

Further, like the driver monolithic type active matrix circuit substrate 3 of the third embodiment described above, the channel region 29a of the peripheral drive circuit TFT 41 is formed.
The film thickness d1 of the first interlayer insulating film 124 provided between the lower conductive film 23 and the lower conductive film 23 is the same as that of the first interlayer insulating film 124 provided between the channel region 29a of the pixel TFT 42 and the lower light shielding film 22. It is thinner than the film thickness d2 (d1 <d2). This enhances the effect of the lower conductive film 23 as a gate electrode, prevents the generation of parasitic capacitance between the lower light-shielding film 22 and the semiconductor layer 25 of the pixel TFT 42, and prevents the pixel TFT 42 from turning off. It is possible to prevent the potential of the electrode 39 from decreasing.

The driver monolithic active matrix circuit board 4 shown in FIG. 13 is the same as the second embodiment described above.
The step of adding impurities and forming the gate electrode contact hole 27, the gate electrode 28 and the auxiliary capacitance electrode 28a in the third embodiment, and the lower light shielding film 22 of the third embodiment,
Since it can be manufactured by combining the step of forming the lower conductive film 23 and the step of forming the first interlayer insulating film 124, and the other steps are the same as those of the first embodiment, a detailed description of the manufacturing method will be given. Omit it.

The semiconductor devices according to the first to fourth embodiments of the present invention described above are examples of the semiconductor device manufactured according to the present invention, and the materials used for each part of the semiconductor device and the film thickness of each part. The method of forming each part is not limited to this.

As described in the first to fourth embodiments of the present invention, in order to form the N-type MOS FET whose carrier is a conduction electron as the TFT 41 for the peripheral drive circuit, the semiconductor layer 25 or the semiconductor is used. Although pentavalent impurities that are sources of conduction electrons are used as impurities added to the layer 125, trivalent impurities that are sources of holes, such as boron or gallium, are not limited thereto. By using it, a P-type MOS FET whose carrier is a hole may be formed.

[0077]

As described above, according to the present invention, in the channel region, in addition to the vicinity of the surface facing the gate electrode, the vicinity of the surface facing the conductive film is provided when the peripheral drive circuit transistor is turned on. Since it can be used as a region through which a current passes, high mobility and high on-characteristics can be given to a peripheral driver circuit transistor provided in a semiconductor device, and a high-performance peripheral driver circuit transistor can be obtained.

Further, according to the present invention, it is possible to improve the performance of the peripheral drive circuit transistor by providing a conductive film in the peripheral drive circuit section without increasing the number of manufacturing steps.

Further, according to the present invention, since the light-shielding conductive film provided in the display section and the gate electrode of the pixel transistor can have different potentials, the potential of the pixel electrode decreases when the pixel transistor is off. This can be prevented, and the display quality of a liquid crystal display device using such a semiconductor device can be improved.

Further, according to the present invention, the effect of the conductive film of the peripheral drive circuit section as the gate electrode is enhanced, and the parasitic capacitance between the light-shielding conductive film of the display section and the semiconductor layer of the pixel transistor is generated. It is possible to prevent the potential of the pixel electrode from decreasing when the pixel transistor is turned off.

Further, according to the present invention, the conductive film of the peripheral drive circuit portion used as the second gate electrode can apply an electric field to all regions of the channel region of the peripheral drive circuit transistor. Therefore, the effect of the conductive film of the peripheral drive circuit section as a gate electrode can be enhanced.

Further, according to the present invention, since the low-concentration impurity region is arranged at a position facing the end of the conductive film of the peripheral drive circuit section, deterioration of characteristics of the peripheral drive circuit transistor over time can be suppressed. You can

Further, according to the present invention, the light-shielding conductive film provided in the peripheral drive circuit portion and electrically connected to the gate electrode is used for reducing the light incident on the pixel transistor and suppressing the increase of the off current. Since it can be formed simultaneously with the light-shielding conductive film provided in the display portion, a semiconductor device having a high-performance peripheral driver circuit transistor can be manufactured without increasing the number of steps.

Further, according to the present invention, between the channel region of the peripheral driving circuit transistor and the light-shielding conductive film of the peripheral driving circuit portion, between the channel region of the pixel transistor and the light-shielding conductive film of the display portion. Film thickness d2 of the insulating film provided in
Since an insulating film having a smaller film thickness d1 (d1 <d2) can be provided, the effect of the light-shielding conductive film in the peripheral driver circuit portion as a gate electrode can be improved and the light-shielding conductive film in the display portion and the pixel can be formed. It is possible to prevent generation of parasitic capacitance between the transistor and the semiconductor layer, and to prevent decrease in the potential of the pixel electrode when the pixel transistor is off.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a driver monolithic active matrix circuit board 1.

FIG. 2 is a diagram showing a state in which up to a gate electrode 28 is formed in the peripheral drive circuit section 11 of the driver monolithic active matrix circuit substrate 1 shown in FIG.

FIG. 3 is a diagram showing a state in which a lower light-shielding film 22, a lower conductive film 23, and a first interlayer insulating film 24 are formed on a quartz substrate 21.

FIG. 4 is a diagram showing a state in which a semiconductor layer 25 and a second interlayer insulating film 26 are formed on the first interlayer insulating film 24.

FIG. 5 is a diagram showing a state in which a gate electrode contact hole 27, a gate electrode 28, an auxiliary capacitance electrode 28a, a channel region 29a, a source region 29b and a drain region 29c are formed.

FIG. 6 is a diagram showing a state in which a gate electrode contact hole 27 is formed in the peripheral drive circuit section 11.

FIG. 7 is a diagram showing a state in which a third interlayer insulating film 30, a source electrode contact hole 31, and a drain electrode contact hole 32 are formed.

FIG. 8 shows a source electrode 33, a drain electrode 34 and a fourth electrode.
FIG. 6 is a diagram showing a state in which the interlayer insulating film 35 of FIG.

FIG. 9 is a diagram showing a state in which an upper light-shielding film 36, a fifth interlayer insulating film 37, a pixel electrode contact hole 38, and a pixel electrode 39 are formed.

FIG. 10 is a cross-sectional view showing a schematic configuration of a driver monolithic active matrix circuit board 2.

11 is a diagram showing a state in which up to a gate electrode 28 is formed in the peripheral drive circuit portion 11 of the driver monolithic active matrix circuit substrate 2 shown in FIG.

FIG. 12 is a cross-sectional view showing a schematic configuration of a driver monolithic active matrix circuit board 3.

FIG. 13 is a cross-sectional view showing a schematic configuration of a driver monolithic active matrix circuit board 4.

FIG. 14 is a cross-sectional view showing a schematic configuration of a driver monolithic active matrix circuit board 5.

[Explanation of symbols]

1, 2, 3, 4 driver monolithic active matrix circuit board 11 peripheral drive circuit section 12 display section 21 quartz substrate 22 lower layer light-shielding film 23 lower layer conductive film 24, 124 first interlayer insulating film 25, 125 semiconductor layer 26 second Interlayer insulating film 27 gate electrode contact hole 28 gate electrode 28a auxiliary capacitance electrode 29a channel region 29b source region 29c drain region 29d LDD region 30 third interlayer insulating film 31 source electrode contact hole 32 drain electrode contact hole 33 source electrode 34 drain Electrode 35 Fourth interlayer insulating film 36 Upper light shielding film 37 Fifth interlayer insulating film 38 Pixel electrode contact hole 39 Pixel electrode 40 Conductive film 41 Peripheral drive circuit TFT 42 Pixel TFT 124a Pixel lower layer insulating film 124b Upper layer insulating film

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H092 GA59 JA24 JA40 JA44 JB54                       JB57 MA27 MA30 NA22 PA06                       PA09 RA05                 5F110 AA01 AA07 BB02 CC02 DD03                       DD13 EE05 EE09 EE14 EE30                       FF02 FF09 FF23 GG02 GG13                       GG25 HJ01 HJ13 HJ23 HL06                       HL12 HM15 NN03 NN04 NN23                       NN24 NN42 NN44 NN45 NN46                       NN48 NN72 NN73 NN78 PP01                       PP03 PP10 QQ24

Claims (8)

[Claims] 1. A display unit including a plurality of pixel electrodes arranged in a matrix on a substrate and a plurality of pixel transistors connected to each pixel electrode, and a peripheral drive circuit provided around the display unit. A peripheral drive circuit unit including a transistor, wherein the peripheral drive circuit transistor is formed by laminating a conductive layer on an upper layer side of a channel region formed of a semiconductor layer with an insulating film interposed therebetween. A conductive film is provided under the semiconductor layer via an insulating film in the peripheral drive circuit section, and the conductive film provided under the semiconductor layer is the gate electrode. A semiconductor device, which is electrically connected to. 2. The pixel transistor includes an insulating film on an upper layer side of a channel region formed of a semiconductor layer,
A conductive film is provided in the peripheral drive circuit section, wherein the display section is provided with a gate electrode formed by stacking conductive layers, and the display section is provided with a light-shielding conductive film below the semiconductor layer via an insulating film. The semiconductor device according to claim 1, wherein the film is a light-shielding conductive film, and is formed at the same time as the light-shielding conductive film provided in the display portion. 3. The semiconductor device according to claim 2, wherein the light-shielding conductive film provided in the display section is not electrically connected to the gate electrode of the pixel transistor. 4. The film thickness d1 of the insulating film provided between the channel region of the peripheral drive circuit transistor and the conductive film of the peripheral drive circuit section is set such that the channel region of the pixel transistor and the light shield of the display section. 4. The semiconductor device according to claim 2, wherein the thickness is smaller than the thickness d2 of the insulating film provided between the conductive conductive film and the conductive conductive film (d1 <d2). 5. The conductive film of the peripheral drive circuit portion is provided so as to correspond to the channel region of the transistor for the peripheral drive circuit, and when the channel region is projected onto the surface of the conductive film facing the channel region. The semiconductor device according to any one of claims 1 to 4, wherein the projection image of the channel region is provided so as to be included in the surface of the conductive film. 6. The semiconductor layer of the transistor for peripheral drive circuit comprises: the channel region, an impurity-doped source and drain region formed on both sides of the channel region and extending along the channel region, the channel region and the source. A low-concentration impurity region which is formed between the region and the channel region and the drain region and which is doped with an impurity at a lower concentration than the source region and the drain region, and the conductive film of the peripheral drive circuit section, When projecting the channel region and the low-concentration impurity region on the surface of the conductive film, which is provided so as to correspond to the channel region of the transistor for peripheral driving circuit, the channel region and at least a portion near the channel region are provided. The projection image of the end portion of the low concentration impurity region is provided so as to be included in the surface of the conductive film. The semiconductor device according to any one of claims 1 to 4, which is a characteristic. 7. A display unit including a plurality of pixel electrodes arranged in a matrix and a plurality of pixel transistors connected to each pixel electrode on a substrate, and a peripheral drive circuit provided around the display unit. A method of manufacturing a semiconductor device having a peripheral drive circuit unit including a transistor, comprising: forming a light-shielding conductive film on a substrate; forming an insulating film on the light-shielding conductive film; A step of sequentially stacking a semiconductor layer to be a channel region, an insulating film, and a conductive layer to be a gate electrode on the insulating film; a part of the light-shielding conductive film which is predetermined to be the peripheral drive circuit part; And a step of electrically connecting with a gate electrode. 8. The step of forming an insulating film on the light-shielding conductive film includes the step of forming a lower-layer insulating film on the light-shielding conductive film, and the step of forming a predetermined portion to become the peripheral drive circuit section. 8. The method of manufacturing a semiconductor device according to claim 7, further comprising: a step of removing the lower insulating film by etching; and a step of forming an upper insulating film on the surface of the substrate after the etching.