JP2003029298A - Thin-film semiconductor device, electro-optical device, electronic equipment, thin-film semiconductor device, and method of manufacturing electro-optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-film semiconductor device, an electro-optical device, an electronic apparatus, a thin-film semiconductor device, and an electro-optical device capable of satisfying dimensional accuracy, improving productivity and reducing material cost. To provide a method for manufacturing a device. An active matrix substrate for a liquid crystal device is provided.
No. 0 has a first photosensitive resin 7 provided with a contact hole 7 'and a second photosensitive resin 13 formed on the upper side of the photosensitive resin layer. 13,
A smaller contact hole 13 'is formed at a position overlapping the contact hole 7'. The first photosensitive resin 13 is a negative acrylic resin layer, and the second photosensitive resin 13 is a positive acrylic resin layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film semiconductor device in which a photosensitive resin layer is formed on a substrate, an electro-optical device using this thin film semiconductor device as an active matrix substrate, an electronic device using the same, and a thin film semiconductor. The present invention relates to a device and a method for manufacturing an electro-optical device.

[0002]

2. Description of the Related Art Electro-optical devices such as liquid crystal devices are used as direct-view type or projection type display devices for various equipment. In such an electro-optical device, in an active matrix type liquid crystal device, an active matrix substrate and a counter substrate which are arranged to face each other are bonded with a sealant, and in a region partitioned by the sealant between the substrates. A liquid crystal as an electro-optical material is held.

In a reflective or semi-transmissive / semi-reflective active matrix type liquid crystal device, a light reflection film for reflecting external light incident from the counter substrate side toward the counter substrate is transparent. The pixel electrodes are formed on the lower layer side, light incident from the counter substrate side is reflected on the active matrix substrate side, and an image is displayed by the light emitted from the counter substrate side. However, if the directionality of the light reflected by the light reflection film is strong, the viewing angle dependency such that the brightness differs depending on the angle at which the image is viewed becomes noticeable.

Therefore, conventionally, when manufacturing an active matrix substrate, as shown in FIG. 15A, a first photosensitive material such as acrylic resin is formed on the surface of the second interlayer insulating film 5 (surface protection film). After the resin 13 ″ is applied thickly, the first photosensitive resin 13 ″ is exposed through the exposure mask 510 ″ and developed to form an unevenness forming layer having a predetermined pattern as shown in FIG. 15B. After forming 13a, as shown in FIG. 15 (C), a second photosensitive resin 7 such as an acrylic resin is also applied on the upper layer side of the unevenness forming layer 13a, and the second photosensitive resin 7 is applied. 15D, the upper layer film 7a having the contact holes is formed by exposing through the exposure mask 520 and developing, and therefore, when the light reflecting film is formed on the surface of the upper layer film 7a. , Light on its surface Uneven pattern of abuse is formed,
The shape of this uneven pattern is smooth.

In such a manufacturing method, since a positive type photosensitive resin has been conventionally used as the photosensitive resin 13 ″, 7, as shown in FIGS. 15 (A) and 15 (C),
Ultraviolet rays are irradiated to the portions where the photosensitive resins 13 ″ and 7 are to be removed through the light transmitting portions 511 ″ and 521 of the exposure masks 510 ″ and 520.

A TFT 30 for pixel switching is formed on the active matrix substrate 10, and the photosensitive resins 13 ″ and 7 are both left as an interlayer insulating film in a region where the TFT 30 is formed. ,
When using the photosensitive resin 13 ″, 7 as an interlayer insulating film, contact holes 13 ′, 7 ′ are formed at positions overlapping with each other by exposure and development in the photolithography process shown in FIGS. 15A and 15C. Here, the contact hole 13 'is as large as about 5 .mu.m to about 10 .mu.m and the dimensional accuracy is not so severe, but the contact hole 7'is as small as 5 .mu.m and high dimensional accuracy is required.

[0007]

However, if the positive type resin is used for both the first photosensitive resin 13 ″ and the second photosensitive resin 7 as in the conventional case, the following problems will occur. First, the positive type photosensitive resin has an advantage that the resolution is high, but it has a problem that the tact of the exposure is long because the exposure time needs to be set long because of the poor sensitivity. Further, when the photosensitive resin is applied by the spin coating method, the resin is thickly applied in the peripheral portion as compared with the center of the substrate, but in the case of the positive type photosensitive resin,
To remove the photosensitive resin from the thickly formed peripheral portion, it is necessary to perform normal exposure and then separately expose the peripheral portion, so that the productivity is low. further,
The positive type photosensitive resin is more expensive than the negative type photosensitive resin.

However, if the negative photosensitive resin is used for both the first photosensitive resin and the second photosensitive resin, the above-mentioned problems can be solved, but the negative photosensitive resin has a low resolution. Therefore, when it is used as an interlayer insulating film, there is a problem that contact holes with high dimensional accuracy cannot be formed.

In view of the above problems, the object of the present invention is to
Sufficient dimensional accuracy is required when forming the photosensitive resin,
It is an object of the present invention to provide a thin film semiconductor device, an electro-optical device, an electronic device, a thin film semiconductor device, and a method for manufacturing an electro-optical device that can be satisfied, and can improve productivity and reduce material cost.

[0010]

In order to solve the above problems, according to the present invention, a first photosensitive resin layer having a first contact hole is provided on the front surface side of a substrate, and the first photosensitive resin layer. A second photosensitive resin layer formed on the upper side of the resin layer, and the second photosensitive resin layer has a second photosensitive resin layer at a position overlapping the first contact hole, In a thin film semiconductor device having a small second contact hole, the first photosensitive resin layer is a negative type photosensitive resin layer, and the second photosensitive resin layer is a positive type photosensitive resin layer. Is characterized in that.

Further, according to the present invention, the first photosensitive resin is applied on the surface side of the substrate and then exposed and developed to form a first photosensitive resin layer having a first contact hole, Next, after coating the second photosensitive resin on the upper layer side of the first photosensitive resin layer, exposing and developing the second photosensitive resin, and at a position overlapping the first contact hole than the first contact hole. In the method of manufacturing a thin film semiconductor device having a second photosensitive resin layer having a small second contact hole, the first photosensitive resin is a negative photosensitive resin layer, and the second photosensitive resin layer is a negative photosensitive resin layer. The characteristic resin layer is a positive type photosensitive resin.

In the present invention, since it is necessary to form a contact hole for the second photosensitive resin that is small and has a narrow dimensional tolerance, it is necessary to use a positive photosensitive resin having a high resolution. On the other hand, for the first photosensitive resin, a negative type photosensitive resin is used because it is sufficient to form a contact hole that is large and has a wide allowable range of dimensions. Here, the negative-type photosensitive resin has a disadvantage that the resolution is low as compared with the case where the positive-type photosensitive resin is used, but since the sensitivity is high, the exposure time can be shortened. Can be shortened. Also, when a photosensitive resin is applied by spin coating, the resin is applied thicker in the peripheral area than in the center of the substrate, but in the case of a negative type photosensitive resin, the area where the photosensitive resin is desired to be exposed is exposed. Therefore, when the photosensitive resin is removed from the peripheral portion, the peripheral portion may be left shielded by the exposure mask. Therefore, it is possible to save the labor of separately performing the exposure on the peripheral portion after performing the normal exposure, so that the productivity is high. Further, the negative type photosensitive resin is less expensive than the positive type photosensitive resin. Therefore, according to the present invention, it is possible to sufficiently satisfy the required dimensional accuracy when forming the photosensitive resin, and to improve the productivity and reduce the material cost.

In the present invention, the first photosensitive resin layer is, for example, a negative acrylic resin layer, and the second photosensitive resin layer is, for example, a positive acrylic resin layer.

In the present invention, each of the first photosensitive resin layer and the second photosensitive resin layer is formed on the substrate by spin coating, and then exposed and developed.

In the present invention, the first photosensitive resin layer is a concavo-convex forming layer that forms a plurality of concavities and convexities composed of protrusions or holes, and the second photosensitive resin layer covers the concavo-convex forming layer. Thus formed is an upper layer film, and a light reflection film having a concavo-convex pattern for light scattering formed on the surface by the concavities and convexities of the concavo-convex forming layer is formed on the upper layer side of the upper layer film. Since the concavo-convex forming layer is only for forming concavities and convexities, there is no strict requirement for the position where the concavo-convex is formed.

The thin film semiconductor device according to the present invention is, for example,
This is an active matrix substrate used in an active matrix type electro-optical device. In this active matrix substrate, pixel electrodes and pixel switching thin film transistors connected to the pixel electrodes are formed in a matrix, and between the active matrix substrate and a counter substrate arranged to face the active matrix substrate. Holds an electro-optical material such as liquid crystal. Further, on the active matrix substrate, the thin film transistor and the pixel electrode are electrically connected to each other through the contact holes of the first photosensitive resin layer and the second photosensitive resin layer.

The electro-optical device to which the present invention is applied can be used as a display device of electronic equipment such as a mobile phone and a mobile computer.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. In the following description, an example in which the present invention is applied to an active matrix substrate of a liquid crystal device of an active matrix type as a thin film semiconductor device among various electro-optical devices will be described. The liquid crystal device to which the present invention is applied has the same basic structure as that described with reference to FIG. 15, and therefore, corresponding parts will be denoted by the same reference numerals.

(Basic Structure of Electro-Optical Device) FIG.
FIG. 2 is a plan view of the liquid crystal device to which the present invention is applied, together with the respective components, viewed from the counter substrate side, and FIG.
FIG. FIG. 3 is an equivalent circuit diagram of various elements and wirings in a plurality of pixels formed in a matrix in the image display area of the liquid crystal device. In each of the drawings used to describe the present embodiment, the scale of each layer and each member is different in order to make each layer and each member recognizable in the drawing.

In FIG. 1 and FIG. 2, in the liquid crystal device 100 (electro-optical device) of this embodiment, the active matrix substrate 10 (thin film semiconductor device) and the counter substrate 20 are bonded together by a sealing material 52, and the sealing material 52 is used. A liquid crystal 50 as an electro-optical material is sandwiched in the partitioned area (liquid crystal enclosed area). A peripheral partition 53 made of a light-shielding material is formed inside the area where the sealing material 52 is formed, and the peripheral partition 53 defines the image display area 10a.

In a region outside the seal material 52, a data line driving circuit 101 and mounting terminals 102 are formed along one side of the active matrix substrate 10, and scanning lines are formed along two sides adjacent to this one side. The drive circuit 104 is formed. On the remaining one side of the active matrix substrate 10, a plurality of wirings 105 for connecting between the scanning line driving circuits 104 provided on both sides of the image display area are provided, and further, under the peripheral partition 53, etc. are used. do it,
A precharge circuit or a test circuit may be provided.
The active matrix substrate 10 and the counter substrate 2 are provided at least at one corner of the counter substrate 20.
Inter-substrate conductive material 106 for establishing electrical conduction with 0
Are formed.

Instead of forming the data line driving circuit 101 and the scanning line driving circuit 104 on the active matrix substrate 10, for example, a TAB (tape automated, bonding) substrate on which a driving LSI is mounted is used as an active matrix. You may make it electrically and mechanically connect to the terminal group formed in the peripheral part of the board | substrate 10 through an anisotropic conductive film. In the liquid crystal device 100, the type of the liquid crystal 50 used, that is, T
Depending on the operating mode such as N (twisted nematic) mode, STN (super TN) mode, etc., and the normally white mode / normally black mode, a polarizing film, a retardation film, a polarizing plate, etc. are arranged in a predetermined direction. However, the illustration is omitted here.

Further, when the liquid crystal device 100 is configured for color display, an RGB color filter is provided in a region of the counter substrate 20 facing each pixel electrode (described later) of the active matrix substrate 10 together with its protective film. Form.

In the image display area 10a of the liquid crystal device 100 having such a structure, as shown in FIG. 3, a plurality of pixels 100a are arranged in a matrix, and each of these pixels 100a has a plurality of pixels. Pixel electrode 9
a and a pixel switching TFT 30 for driving the pixel electrode 9a are formed, and the pixel signal S
The data line 6a for supplying 1, S2, ...
It is electrically connected to the source of T30. Data line 6
The pixel signals S1, S2 ... Sn to be written in a may be line-sequentially supplied in this order, or may be supplied group by group to a plurality of adjacent data lines 6a. Further, the scanning line 3a is connected to the gate of the TFT 30.
Are electrically connected to each other, and are configured to apply the scanning signals G1, G2 ... Gm to the scanning line 3a in a pulse-wise manner in this order at a predetermined timing. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the pixel signal S1, S2 ... Sn supplied from the data line 6a is generated by turning on the TFT 30 which is a switching element for a certain period. Is written in each pixel at a predetermined timing. In this way, the pixel electrode 9a
The pixel signal S of a predetermined level written in the liquid crystal through the
1, S2, ... Sn are held for a certain period between the counter electrode 21 of the counter substrate 20 shown in FIG.

Here, in the liquid crystal 50, the orientation and order of the molecular assembly are changed by the applied voltage level,
Modulates light and enables gradation display. In the normally white mode, the amount of incident light passing through the liquid crystal 50 portion decreases according to the applied voltage, and in the normally black mode, the incident light changes according to the applied voltage. The amount of light passing through the liquid crystal 50 increases. As a result, light having a contrast according to the pixel signals S1, S2, ... Sn is emitted from the liquid crystal device 100 as a whole.

The held pixel signals S1, S2, ...
.. In order to prevent Sn from leaking, the storage capacitor 60 may be added in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode. For example, the voltage of the pixel electrode 9a is held by the storage capacitor 60 for a time that is three orders of magnitude longer than the time when the source voltage is applied. As a result, the charge retention characteristics are improved, and the liquid crystal device 100 having a high contrast ratio can be realized. As a method of forming the storage capacitor 60, as shown in FIG. 3, when the storage capacitor 60 is formed between the storage capacitor 60 and the capacitance line 3b, which is a wiring for forming the storage capacitor 60, or when it is formed with the preceding scanning line 3a. Either may be formed between them.

(Structure of Active Matrix Substrate 10)
FIG. 4 is a plan view of a plurality of pixel groups adjacent to each other on the active matrix substrate 10 used in the liquid crystal device 100 of this embodiment. FIG. 5 shows a part of the pixel of the liquid crystal device 100 as shown in FIG.
FIG. 6 is a cross-sectional view when cut at a position corresponding to line −A ′. 6A and 6B show TF for pixel switching.
9A and 9B are a cross-sectional view and an enlarged plan view showing an electrically connected portion between T30 and the pixel electrode 9a.

In FIG. 4, a plurality of transparent ITOs (Indium Ti) are formed on the active matrix substrate 10.
The pixel electrodes 9a made of (n oxide) film are formed in a matrix, and the pixel switching TFTs 30 are connected to the respective pixel electrodes 9a. Further, the data line 6a, the scanning line 3a, and the capacitance line 3b are formed along the vertical and horizontal boundaries of the pixel electrode 9a, and T
The FT 30 is connected to the data line 6a and the scanning line 3a. That is, the data line 6a is electrically connected to the high-concentration source region 1d of the TFT 30 through the contact hole, and the pixel electrode 9a is electrically connected to the high-concentration drain region 1e of the TFT 3 through the contact hole. There is. Further, the scanning line 3a extends so as to face the channel region 1a 'of the TFT 30. In addition, storage capacity 6
0 (storage capacitance element) is the TFT 3 for pixel switching
A conductive material of the extended portion 1f of the semiconductor film 1 for forming 0 is used as a lower electrode, and the lower electrode 41 is connected to the scanning line 3b.
The capacitor line 3b in the same layer is overlapped as an upper electrode.

In each of the pixels 100a thus constructed, of the area where the pixel electrode 9a is formed, the area surrounded by the alternate long and short dash line 8'is a transmissive area for displaying in the transmissive mode, which will be described later. The concavo-convex forming layer and the light reflecting film are not formed, and the other region is a reflecting region provided with the concavo-convex forming layer and the light reflecting film which will be described later, and display is performed in the reflection mode here.

As shown in FIG. 5, the cross section of the reflective area taken along the line AA 'is shown in FIG.
On the surface of the transparent substrate 10 'which is the base of
A base protective film 11 made of a silicon oxide film (insulating film) having a thickness of m to 500 nm is formed, and an island-shaped semiconductor film 1a having a thickness of 50 nm to 100 nm is formed on the surface of the base protective film 11.
Are formed. A gate insulating film 2a made of a silicon oxide film having a thickness of about 50 to 150 nm is formed on the surface of the semiconductor film 1a, and a scanning line 3a having a thickness of 300 nm to 800 nm is formed on the surface of the gate insulating film 2a. It passes as an electrode. A region of the semiconductor film 1a that faces the scanning line 3a via the gate insulating film 2a is a channel region 1a '. A source region including a low concentration source region 1b and a high concentration source region 1d is formed on one side of the channel region 1a ', and a drain including a low concentration drain region 1c and a high concentration drain region 1e is formed on the other side. A region is formed.

On the front surface side of the pixel switching TFT 30, a first interlayer insulating film 4 made of a silicon oxide film having a thickness of 300 nm to 800 nm and a thickness of 100 nm to 100 nm are formed.
Second interlayer insulating film 5 made of a 300 nm silicon nitride film
(Surface protection film) is formed. A data line 6 having a thickness of 300 nm to 800 nm is formed on the surface of the first interlayer insulating film 4.
a is formed, and the data line 6a is connected to the first interlayer insulating film 4
Is electrically connected to the high-concentration source region 1d through the contact hole formed in. A drain electrode 6b formed simultaneously with the data line 6a on the surface of the first interlayer insulating film 4.
And the drain electrode 6b is electrically connected to the high-concentration drain region 1e through a contact hole formed in the first interlayer insulating film 4.

As will be described later, a concavo-convex forming layer 13a made of a photosensitive resin such as acrylic resin and an upper layer film 7a are formed in this order on the upper layer of the second interlayer insulating film 5, and the surface of this upper layer film 7a is formed. A light reflection film 8a made of an aluminum film or the like is formed.

On the upper layer of the light reflection film 8a, a transparent pixel electrode 9a made of an ITO film is formed. Pixel electrode 9a
Are laminated directly on the surface of the light reflection film 8a. In addition, the pixel electrode 9a has a first photosensitive resin layer forming the concavo-convex forming layer 13a and a second photosensitive layer forming the upper layer film 7a, as described later with reference to FIGS. 6 (A) and 6 (B). Resin layer,
Also, the drain electrode 6b is electrically connected through the contact holes 13 ', 7', 5'formed in the second interlayer insulating film 5, respectively.

An alignment film 12 made of a polyimide film is formed on the surface side of the pixel electrode 9a. This alignment film 12
Is a film obtained by rubbing a polyimide film.

Further, with respect to the extended portion 1f (lower electrode) extending from the high-concentration drain region 1e, the scanning line 3a is formed via the insulating film (dielectric film) formed simultaneously with the gate insulating film 2a.
The storage capacitor 60 is formed by the capacitance lines 3b in the same layer facing each other as upper electrodes.

The TFT 30 preferably has the LDD structure as described above, but has the offset structure in which the impurity ions are not implanted in the regions corresponding to the low concentration source region 1b and the low concentration drain region 1c. May be. Further, the TFT 30 may be a self-alignment type TFT in which high-concentration source and drain regions are formed in a self-aligned manner by implanting high-concentration impurity ions using the gate electrode (a part of the scanning line 3a) as a mask. .

Further, in the present embodiment, only one gate electrode (scanning line 3a) of the TFT 30 is arranged between the source and drain regions, but a single gate structure is arranged, but two or more gate electrodes are arranged between them. You may. At this time, the same signal is applied to each gate electrode.
By configuring the TFT 30 with a dual gate (double gate) or a triple gate or more in this way, it is possible to prevent a leak current at the junction between the channel and the source-drain region, and reduce the off-time current. If at least one of these gate electrodes has an LDD structure or an offset structure, the off current can be further reduced, and a stable switching element can be obtained.

(Structure of Photosensitive Resin Layer) In FIGS. 4 and 5, each pixel 1 is arranged on the active matrix substrate 10.
In the reflection area of 00a, T of the surface of the light reflection film 8a is
A concave-convex pattern 8g having a convex portion 8b and a concave portion 8c is formed in a region (light-reflecting film forming region) outside the FT30 forming region.

In constructing such a concavo-convex pattern 8g, in the active matrix substrate 10 of this embodiment, an acrylic resin or the like is formed in a region of the lower layer side of the light reflection film 8a, which overlaps the light reflection film 8a in a plane. The concavo-convex forming layer 13a made of the first photosensitive resin is formed thickly on the surface of the second interlayer insulating film 5 to have a thickness of, for example, 2 to 3 μm, and an acrylic resin or the like is formed on the concavo-convex forming layer 13a. The upper layer film 7a made of the second photosensitive resin is laminated thickly, for example, in a thickness of 1 to 2 μm. For this reason, a concavo-convex pattern 8g corresponding to the concavities and convexities of the concavo-convex forming layer 13a is formed on the surface of the reflective film 8a. In the concavo-convex pattern 8g, the upper layer film 7a prevents the edges of the concavo-convex forming layer 13a from appearing. Has become.

Further, in the active matrix substrate 10, both the photosensitive resins 13 and 7 are left as an interlayer insulating film in the region where the TFT 30 is formed, as shown in FIGS. 6 (A) and 6 (B). Further, contact holes 13 'and 7'are formed in each. Both of these contact holes 13 'and 7'overlap with the contact hole 5'of the second interlayer insulating film 5, and electrically connect the pixel electrode 9a and the drain region 1e of the TFT 30 via the drain electrode 6b. I am letting you.

The contact hole 13 'has a large side of 5 .mu.m to 10 .mu.m and the dimensional accuracy is not so severe, but the contact hole 7'is required to have a small side of 5 .mu.m and a high dimensional accuracy.

In manufacturing the active matrix substrate 10 having such a structure, in this embodiment, as will be described later in detail, a negative acrylic resin is used as the first photosensitive resin 13, and the second photosensitive resin is used. A positive acrylic resin is used as the resin 7.

(Structure of Counter Substrate) In FIG. 5, the counter substrate 20 is referred to as a black matrix or a black stripe in a region facing the vertical and horizontal boundary regions of the pixel electrodes 9a formed on the active matrix substrate 10. A light shielding film 23 is formed, and on the upper layer side thereof,
A counter electrode 21 made of an ITO film is formed. An alignment film 22 made of a polyimide film is formed on the upper layer side of the counter electrode 21, and the alignment film 22 is a film obtained by subjecting the polyimide film to a rubbing treatment.

(Display Operation of Liquid Crystal Device 100) In the liquid crystal device 100 thus configured, the light reflecting film 8a made of an aluminum film or the like is formed below the pixel electrode 9a. Therefore, light incident from the counter substrate 20 side can be reflected on the active matrix substrate 10 side and emitted from the counter substrate 20 side. Therefore, if the liquid crystal 50 performs light modulation for each pixel 100a during this period, A desired image can be displayed using light (reflection mode).

In the liquid crystal device 100, the light reflection film 8a is arranged so as to avoid the area surrounded by the alternate long and short dash line 8'in FIG.
Since it is formed, it also functions as a semi-transmissive / semi-reflective liquid crystal device. That is, the light emitted from the backlight device (not shown) arranged on the active matrix substrate 10 side is incident on the active matrix substrate 10 side, and then the pixel electrode 9a is formed in each pixel 100a. Among the regions, the light is transmitted to the counter substrate 20 side through the transmissive region where the light reflection film 8a is not formed. Therefore, if the liquid crystal 50 performs light modulation for each pixel 100a, a desired image can be displayed using the light emitted from the backlight device (transmission mode).

Further, in the present embodiment, the unevenness forming layer 13a is formed in a region of the lower layer side of the light reflecting film 8a which overlaps the light reflecting film 8a in plan view, and the unevenness formed by the unevenness forming layer 13a is utilized. Thus, an uneven pattern 8g for light scattering is formed on the surface of the light reflection film 8a. Further, in the concavo-convex pattern 8g, the upper layer film 7a prevents the edges of the concavo-convex forming layer 13a from appearing. Therefore, when an image is displayed in reflection mode, the image is displayed with scattered reflected light,
Small viewing angle dependence.

[Manufacturing Method of Active Matrix Substrate 10] A method of manufacturing the active matrix substrate 10 having such a structure will be described with reference to FIGS. 7 to 11. 7 to 11 are all process cross-sectional views showing the method for manufacturing the active matrix substrate 10 of the present embodiment. In each of the drawings, the cross section of the TFT formation region and the light reflection film formation region (reflection region) is shown. It is shown.

First, as shown in FIG. 7 (A), after preparing a substrate 10 'made of glass or the like that has been cleaned by ultrasonic cleaning or the like, the substrate temperature is set to 150 ° C to 450 ° C.
A base protection film 11 made of a silicon oxide film is formed on the entire surface of the substrate 10 'by a plasma CVD method at a thickness of 300 nm to 500 n.
It is formed to a thickness of m. As the raw material gas at this time, for example, a mixed gas of monosilane and laughing gas, TEOS and oxygen, or disilane and ammonia can be used.

Next, under the temperature condition of the substrate temperature of 150 ° C. to 450 ° C., the semiconductor film 1 made of an amorphous silicon film is formed on the entire surface of the substrate 10 ′ by the plasma CVD method at 50 nm to 50 nm.
It is formed to a thickness of 100 nm. As the raw material gas at this time, for example, disilane or monosilane can be used. Next, the semiconductor film 1 is irradiated with laser light to perform laser annealing. As a result, the amorphous semiconductor film 1 is once melted and crystallized through a cooling and solidifying process.
At this time, the irradiation time of the laser beam to each area is very short, and the irradiation area is local to the entire substrate, so that the entire substrate is not heated to a high temperature at the same time. Therefore, even if a glass substrate or the like is used as the substrate 10 ', deformation or cracking due to heat does not occur.

Next, a resist mask 551 is formed on the surface of the semiconductor film 1 by using a photolithography technique, and the semiconductor film 1 is etched through the resist mask 551, as shown in FIG. 7B. The island-shaped semiconductor film 1a (active layer) is formed.

Next, under the temperature condition of 350 ° C. or lower, the gate insulating film 2 made of a silicon oxide film or the like is formed on the entire surface of the substrate 10 ′ by the CVD method or the like on the surface of the semiconductor film 1 a.
It is formed to a thickness of 0 nm to 150 nm. As the raw material gas at this time, for example, a mixed gas of TEOS and oxygen gas can be used. The gate insulating film 2 formed here is
A silicon nitride film may be used instead of the silicon oxide film.

Next, although not shown, impurity ions are implanted into the extended portion 1f of the semiconductor film 1a through a predetermined resist mask to form a storage capacitor 60 between the impurity line and the capacitance line 3b. Form electrodes.

Next, as shown in FIG. 7C, an aluminum film, a tantalum film, a molybdenum film, or a metal thereof for forming the scanning lines 3a or the like is formed on the entire surface of the substrate 10 'by a sputtering method or the like. After the conductive film 3 made of an alloy film containing any of the above as a main component is formed to a thickness of 300 nm to 800 nm, a resist mask 552 is formed by a photolithography technique.

Next, the conductive film 3 is dry-etched through the resist mask 552, and as shown in FIG.
The scanning line 3a (gate electrode), the capacitance line 3b, etc. are formed.

Next, on the side of the pixel TFT section and the N-channel TFT section (not shown) of the drive circuit, using the scanning line 3a and the gate electrode as a mask, about 0.1 × 10 ¹³ / cm ² 〜.
By implanting low-concentration impurity ions (phosphorus ions) at a dose of about 10 × 10 ¹³ / cm ² , the low-concentration source region 1b and the low-concentration drain region 1c are formed in a self-aligned manner with respect to the scanning line 3a. Here, since it is located directly below the scanning line 3a, the portion into which the impurity ions are not introduced becomes the channel region 1a 'which remains the semiconductor film 1a.

Next, as shown in FIG. 8A, the pixel TF
At the T portion, a resist mask 553 wider than the scanning line 3a (gate electrode) is formed to add high concentration impurity ions (phosphorus ions) to about 0.1 × 10 ¹⁵ / cm ² to about 10 × 10 5.
Implanting with a dose amount of ¹⁵ / cm ² and high-concentration source region 1
d and the drain region 1e are formed.

Instead of these impurity introduction steps, a high-concentration impurity (phosphorus ion) is implanted with a resist mask wider than the gate electrode formed without implanting a low-concentration impurity, and the source region of the offset structure is formed. And the drain region may be formed. Further, it goes without saying that a source region and a drain region having a self-aligned structure may be formed by implanting a high-concentration impurity using the scanning line 3a as a mask.

Although not shown, the N-channel TFT section of the peripheral drive circuit section is formed by such a process, but at this time, the P-channel TFT section is covered with a mask. Further, when forming the P-channel TFT portion of the peripheral drive circuit, the pixel portion and the N-channel TFT portion are covered and protected with a resist, and the gate electrode is used as a mask to form about 0.1 × 10 ¹⁵ / cm ² to about By implanting boron ions with a dose amount of 10 × 10 ¹⁵ / cm ² , P-channel source / drain regions are formed in a self-aligned manner. At this time, as in the case of forming the N-channel TFT section, the gate electrode is used as a mask to form about 0.1 × 10 ¹³ / cm ² to about 10 ×
A low-concentration impurity (boron ion) is introduced at a dose amount of 10 ¹³ / cm ² to form a low-concentration region in the polysilicon film, and then a mask wider than the gate electrode is formed to form a high-concentration impurity (boron ion). Boron ion) about 0.1 × 10 ¹⁵ / cm
² to about 10 × 10 ¹⁵ / cm ^{2 with} a dose amount,
The source region and the drain region of the LDD structure (lightly doped drain structure) may be formed. Alternatively, the source region and the drain region of the offset structure may be formed by implanting a high-concentration impurity (phosphorus ion) in a state where a mask wider than the gate electrode is formed without implanting a low-concentration impurity. By these ion implantation steps, CMOS can be realized and the peripheral drive circuit can be built in the same substrate.

Next, as shown in FIG. 8B, the scanning line 3
A first interlayer insulating film 4 made of a silicon oxide film or the like is formed on the surface side of a by a CVD method or the like to have a thickness of 300 nm to 800 nm. The source gas at this time is, for example, TE
A mixed gas of OS and oxygen gas can be used.

Next, a resist mask 554 is formed by using the photolithography technique.

Next, the first mask is formed through the resist mask 554.
The interlayer insulating film 4 is dry-etched, and as shown in FIG. 8C, contact holes 4'are formed in the first interlayer insulating film 4 at the portions corresponding to the source region and the drain region.
(See FIGS. 6A and 6B) and the like are formed.

Next, as shown in FIG. 8D, an aluminum film, a tantalum film, a molybdenum film or the like for forming the data line 6a (source electrode) or the like is formed on the surface side of the first interlayer insulating film 4. The conductive film 6 made of an alloy film containing any of these metals as a main component is formed to a thickness of 300 nm by a sputtering method or the like.
After forming to a thickness of ˜800 nm, a resist mask 555 is formed by using a photolithography technique.

Next, the conductive film 6 is dry-etched through the resist mask 555 to form the data line 6a and the drain electrode 6b as shown in FIG. 9A.

Next, as shown in FIG. 9B, the second interlayer insulating film 5 made of a silicon nitride film or the like is formed on the surface side of the data line 6a and the drain electrode 6b by the CVD method or the like.
Is formed to a film thickness of 100 nm to 300 nm, and then a resist mask 556 for forming a contact hole or the like in the second interlayer insulating film 5 by using a photolithography technique.
To form.

Next, a second mask is formed through the resist mask 556.
Dry etching is performed on the interlayer insulating film 5, and as shown in FIG. 9C, the drain electrode 6 of the second interlayer insulating film 5 is formed.
The contact hole 5 '(FIG.
(See (A) and (B)).

Next, as shown in FIG. 10A, the surface of the second interlayer insulating film 5 is spin-coated with a thick first photosensitive resin 13 made of acrylic resin, for example, 2
After being applied to a thickness of ˜3 μm, the photosensitive resin 13 is exposed,
By developing, as shown in FIG. 10B, the concavo-convex forming layer 13a is formed in a region of the lower layer side of the light reflection film 8a, which planarly overlaps with the light reflection film 8a. Here, the first photosensitive resin 13 is left as an interlayer insulating film having a contact hole 13 '(see FIGS. 6A and 6B) in the formation region of the TFT 30.

When the concavo-convex forming layer 13a is formed by using such a photolithography technique, in the present embodiment, the first
A negative acrylic resin is used as the photosensitive resin 13. For this reason, as shown in FIG. 10A, ultraviolet rays are radiated to the portion where the first photosensitive resin 13 is to be left through the transparent portion 511 of the exposure mask 510, and the first photosensitive resin 13 is exposed. The portion to be removed is shielded from ultraviolet rays by the light shielding portion 512.

Next, as shown in FIG. 10C, the second photosensitive resin 7 made of acrylic resin is thickened on the surface side of the second interlayer insulating film 5 and the concavo-convex forming layer 13a by spin coating. To a thickness of, for example, 1 to 2 μm,
The photosensitive resin 7 is exposed and developed to form an upper layer film 7a having contact holes 7 '(see FIGS. 6A and 6B) as shown in FIG. 10D.

When the upper layer film 7a is formed by using such a photolithography technique, a positive acrylic resin is used as the second photosensitive resin 7 in this embodiment. Therefore, as shown in FIG. 10C, the second photosensitive resin 7
Is irradiated with ultraviolet rays through the light transmitting portion 521 of the exposure mask 520 to remove the second photosensitive resin 7
The portion to be left behind is shielded from ultraviolet rays by the light shielding portion 522.

Next, as shown in FIG. 11A, a metal film 8 having reflectivity such as an aluminum film is formed on the surface of the upper layer film 7a by a sputtering method or the like, and then a photolithography technique is used. A resist mask 557 is formed.

Next, the metal film 8 is etched through the resist mask 557, and as shown in FIG.
The light reflecting film 8a is left in a predetermined area. On the surface of the light reflection film 8a thus formed, a concavo-convex pattern 8g having a thickness of 500 nm or more, further 800 nm or more is formed by the concavo-convex forming layer 13a, and the concavo-convex pattern 8g is formed by the upper layer film 7a. No, it has a gentle shape.

Next, as shown in FIG. 11C, IT having a thickness of 40 nm to 200 nm is provided on the surface side of the light reflecting film 8a.
After forming the O film 9 by a sputtering method or the like, a resist mask 558 is formed by using a photolithography technique.

Next, IT is performed through the resist mask 558.
By etching the O film 9, as shown in FIG. 11D, the pixel electrode 9a electrically connected to the drain electrode 6b is formed.
To form.

Thereafter, as shown in FIG. 5, a polyimide film (alignment film 12) is formed on the surface side of the pixel electrode 9a. To this end, a polyimide varnish prepared by dissolving 5 to 10% by weight of polyimide or polyamic acid in a solvent such as butyl cellosolve or n-methylpyrrolidone is flexographically printed, and then heated and cured (baked). Then, the substrate on which the polyimide film is formed is rubbed in a certain direction with a puff cloth made of rayon fibers to arrange the polyimide molecules in a certain direction near the surface. As a result, the liquid crystal molecules are aligned in a certain direction due to the interaction between the liquid crystal molecules filled later and the polyimide molecules.

As a result, the active matrix substrate 10
Is completed.

(Effect of this embodiment) As described above, in this embodiment,
As shown in FIGS. 6A and 6B, the first photosensitive resin 1
Of the third and second photosensitive resins 7, the second photosensitive resin 7 on the upper layer side needs to be formed with a contact hole 7 ′ that is small and has a narrow dimensional tolerance. While a high positive type photosensitive resin is used, the first photosensitive resin 13 on the lower layer side has a large contact hole 1 with a wide allowable range of dimensions.
Since it is sufficient to form 3 ', a negative photosensitive resin is used. Here, the negative photosensitive resin (first photosensitive resin 1
Although 3) has the disadvantage of low resolution, it has a high sensitivity, so that the exposure time can be shortened as compared with the case where a positive photosensitive resin is used, so the exposure tact can be shortened.

Moreover, since the large contact hole 13 'is formed in the lower first photosensitive resin 13, the contact hole 7'formed in the upper second photosensitive resin 7 is formed.
The opening edge has a smooth taper shape that is obliquely upward. Therefore, disconnection is less likely to occur at the portions electrically connected through the contact holes 13 'and 7', and the reliability of the electrically connected portions is high.

Further, in this embodiment, the concavo-convex forming layer 13 is formed.
When forming a, the first coating applied to the entire surface of the substrate 10 '
Since the photosensitive resin 13 of is removed over a wide area,
From this point of view, it is easier to perform exposure when a negative photosensitive resin is used.

Further, a photosensitive resin (first photosensitive resin 1
When 3) is applied by the spin coating method, the resin is thickly applied in the peripheral portion as compared with the center of the substrate, but in the case of the negative type photosensitive resin, as described with reference to FIG. In addition, since it is sufficient to expose the region where the photosensitive resin is desired to be left, when the photosensitive resin is removed from the peripheral portion, the peripheral portion may be left shielded. Therefore, it is possible to save the labor of separately performing the exposure on the peripheral portion after performing the normal exposure, so that the productivity is high.

Furthermore, the negative type photosensitive resin is less expensive than the positive type photosensitive resin.

Therefore, according to this embodiment, the photosensitive resin 7,
In forming 13, the required dimensional accuracy can be sufficiently satisfied, and productivity can be improved and material cost can be reduced.

[Other Embodiments] Also in the above embodiment, an active matrix liquid crystal device using TFTs as pixel switching elements has been described as an example, but an electro-optical device using an electro-optical material other than liquid crystal, or other The present invention may be applied to the thin film semiconductor device.

[Application of Liquid Crystal Device to Electronic Equipment] The reflective or semi-transmissive / semi-reflective liquid crystal device 100 configured as described above can be used as a display portion of various electronic equipments. FIG. 12, FIG. 13, and FIG.
This will be described with reference to FIG.

FIG. 12 is a block diagram showing a circuit configuration of an electronic device using the liquid crystal device according to the present invention as a display device.

In FIG. 12, the electronic equipment has a display information output source 70, a display information processing circuit 71, a power supply circuit 72, a timing generator 73, and a liquid crystal device 74. The liquid crystal device 74 also includes a liquid crystal display panel 75 and a drive circuit 76. As the liquid crystal device 74, the liquid crystal device 100 described above can be used.

The display information output source 70 is a ROM (Read
Only Memory), RAM (Random)
A memory such as an Access Memory), a storage unit such as various disks, a tuning circuit that tunes and outputs a digital image signal, and the like, and a display such as an image signal of a predetermined format based on various clock signals generated by the timing generator 73. Information is supplied to the display information processing circuit 71.

The display information processing circuit 71 includes various well-known circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and executes processing of input display information. , And supplies the image signal to the drive circuit 76 together with the clock signal CLK. The power supply circuit 72 supplies a predetermined voltage to each component.

FIG. 13 shows a mobile personal computer which is an embodiment of the electronic apparatus according to the present invention. The personal computer 80 shown here has a main body 82 having a keyboard 81, and a liquid crystal display unit 83. The liquid crystal display unit 83 is configured to include the liquid crystal device 100 described above.

FIG. 14 shows a portable telephone which is another embodiment of the electronic apparatus according to the present invention. The mobile phone 90 shown here has a plurality of operation buttons 91 and a display unit including the liquid crystal device 100 described above.

[0090]

As described above, in the present invention, it is necessary to form a contact hole having a small size and a narrow dimensional tolerance range in the second photosensitive resin. First, while using a resin
For the photosensitive resin of (3), a negative type photosensitive resin is used because a contact hole having a large size and a wide allowable range of dimensions may be formed. Here, the negative-type photosensitive resin has a disadvantage that the resolution is low, but since the sensitivity is high, the exposure time can be shortened as compared with the case where the positive-type photosensitive resin is used. Can be shortened. In addition, when the photosensitive resin is applied by spin coating, the resin is applied thicker in the peripheral area compared to the center of the substrate, but in the case of the negative type photosensitive resin, the area where the photosensitive resin is desired to remain exposed Therefore, when the photosensitive resin is removed from the peripheral portion, the peripheral portion may be left shielded from light. Therefore, it is possible to save the labor of separately performing the exposure on the peripheral portion after performing the normal exposure, so that the productivity is high. Further, the negative type photosensitive resin is less expensive than the positive type photosensitive resin. Therefore, according to the present invention,
When forming the photosensitive resin, the required dimensional accuracy can be sufficiently satisfied, and productivity can be improved and material cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a liquid crystal device to which the present invention is applied, as viewed from a counter substrate side.

FIG. 2 is a sectional view taken along the line HH ′ of FIG.

FIG. 3 is an equivalent circuit diagram of various elements, wirings, etc. formed in a plurality of pixels arranged in a matrix in the liquid crystal device shown in FIG.

FIG. 4 is a plan view showing a configuration of each pixel formed on an active matrix substrate in a liquid crystal device to which the present invention is applied.

5 is a cross-sectional view of a pixel when cut at a position corresponding to line AA ′ in FIG.

6A and 6B are cross-sectional views showing, in an enlarged scale, an electrical connection portion between a pixel switching TFT and a pixel electrode in an active matrix substrate of a liquid crystal device to which the present invention is applied; It is a top view.

7A to 7D are process cross-sectional views showing a method for manufacturing an active matrix substrate of a liquid crystal device to which the present invention is applied.

8A to 8D are diagrams illustrating a method for manufacturing an active matrix substrate of a liquid crystal device to which the present invention is applied.
FIG. 6 is a process cross-sectional view of each process performed after the process shown in FIG.

9A to 9C show a method for manufacturing an active matrix substrate of a liquid crystal device to which the present invention is applied.
FIG. 6 is a process cross-sectional view of each process performed after the process shown in FIG.

10A to 10D are process cross-sectional views of each process performed subsequent to the process shown in FIG. 9 in the method for manufacturing an active matrix substrate of a liquid crystal device to which the present invention has been applied.

11A to 11D are process cross-sectional views of each process performed subsequent to the process shown in FIG. 10 in the method of manufacturing the active matrix substrate of the liquid crystal device to which the present invention is applied.

FIG. 12 is a block diagram showing a circuit configuration of an electronic device using the liquid crystal device according to the present invention as a display device.

FIG. 13 is an explanatory diagram showing a mobile personal computer as an embodiment of an electronic apparatus using the liquid crystal device according to the present invention.

FIG. 14 is an explanatory diagram of a mobile phone as an embodiment of an electronic device using the liquid crystal device according to the invention.

15A to 15D are process cross-sectional views showing a conventional method for manufacturing a liquid crystal device.

[Explanation of symbols]

1a Semiconductor film 1a 'channel forming region 2 Gate insulating film 3a scanning line 3b Capacitance line 4 First interlayer insulating film 4'Contact hole formed in first interlayer insulating film 5 Second interlayer insulating film 5'Contact hole formed in second interlayer insulating film 6a data line 6b drain electrode 7 Second photosensitive resin for forming upper layer film 7'Contact hole formed in second photosensitive resin 7a Upper layer film 8a Light reflection film 9a Pixel electrode 10 Active matrix substrate (thin film semiconductor device) 11 Base protection film 13 First Photosensitive Resin for Forming Concavo-Convex Forming Layer 13 'Contact hole formed in the first photosensitive resin 13a Concavo-convex forming layer 20 Counter substrate 30 pixel switching TFT 50 liquid crystal 60 storage capacity 100 Liquid crystal device (electro-optical device) 100a pixel 510 and 520 exposure mask 511, 521 Light-transmitting portion of exposure mask 512,522 Light-shielding part of exposure mask

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H092 GA59 HA05 JA25 KA04 MA05                       MA07 MA13 MA17 MA28 MA35                       MA37 NA21 NA27 NA29 RA05                 5C094 AA03 AA43 BA03 BA43 CA19                       DA15 EA04 EA07                 5F110 AA16 AA30 BB02 BB04 CC02                       DD02 DD13 EE03 EE04 EE06                       EE28 EE44 FF02 FF03 FF29                       GG02 GG13 GG25 HJ01 HJ04                       HJ13 HL03 HL04 HL06 HL23                       HM14 HM15 NN03 NN04 NN23                       NN24 NN27 NN35 NN36 NN73                       PP03 QQ11                 5G435 AA01 AA17 BB12 CC09 KK05                       KK09 KK10

Claims (13)

[Claims] 1. A first photosensitive resin layer having a first contact hole on a surface side of a substrate, and a second photosensitive resin layer formed on an upper layer side of the first photosensitive resin layer. Has and
In the thin film semiconductor device, a second contact hole smaller than the first contact hole is formed in the second photosensitive resin layer at a position overlapping with the first contact hole. The thin-film semiconductor device, wherein the resin layer is a negative photosensitive resin layer, and the second photosensitive resin layer is a positive photosensitive resin layer. 2. The method according to claim 1, wherein the first photosensitive resin layer is a negative acrylic resin layer and the second photosensitive resin layer is a positive acrylic resin layer. Thin film semiconductor device. 3. The method according to claim 1, wherein each of the first photosensitive resin layer and the second photosensitive resin layer is applied on the substrate by spin coating, and then exposed.
A thin film semiconductor device characterized by being developed. 4. The method according to any one of claims 1 to 3,
The first photosensitive resin layer is a concavo-convex forming layer that forms a plurality of concavities and convexities composed of protrusions or holes, and the second photosensitive resin layer is an upper layer film formed so as to cover the concavo-convex forming layer. The thin film semiconductor device is characterized in that a light reflecting film having a concavo-convex pattern for light scattering formed on the surface by the concavities and convexities of the concavo-convex forming layer is formed on the upper layer side of the upper layer film. 5. An electro-optical device comprising the thin film semiconductor device as defined in claim 1, wherein the thin film semiconductor device includes a pixel electrode and a pixel switching thin film transistor connected to the pixel electrode. An active matrix substrate formed in a matrix, wherein an electro-optical material is held between the active matrix substrate and a counter substrate arranged to face the active matrix substrate, and the active matrix substrate has: An electro-optical device, wherein the thin film transistor and the pixel electrode are electrically connected to each other through the contact holes of the first photosensitive resin layer and the second photosensitive resin layer. 6. The electro-optical device according to claim 5, wherein the electro-optical substance is liquid crystal. 7. An electronic apparatus comprising the electro-optical device defined in claim 1 as a display section. 8. A first photosensitive resin is applied to the front surface side of the substrate, then exposed and developed to form a first photosensitive resin layer having a first contact hole, and then the first photosensitive resin layer is formed. After applying the second photosensitive resin on the upper layer side of the first photosensitive resin layer,
A method of manufacturing a thin film semiconductor device, which comprises exposing and developing to form a second photosensitive resin layer having a second contact hole smaller than the first contact hole at a position overlapping the first contact hole. The first photosensitive resin is a negative type photosensitive resin layer,
The method for manufacturing a thin film semiconductor device, wherein the second photosensitive resin layer is a positive photosensitive resin. 9. The thin film semiconductor according to claim 8, wherein the first photosensitive resin is a negative acrylic resin layer, and the second photosensitive resin is a positive acrylic resin layer. Device manufacturing method. 10. The method according to claim 8 or 9,
Is coated on the substrate by spin coating, then exposed and developed, and then the second photosensitive resin is coated on the substrate by spin coating, then exposed,
A method of manufacturing a thin film semiconductor device, which comprises developing. 11. The second photosensitive resin according to claim 8, wherein the first photosensitive resin layer is formed as a concavo-convex forming layer that forms a plurality of concavities and convexities composed of protrusions or holes. The layer is formed as an upper layer film that covers the concavo-convex forming layer, and a light reflecting film having a concavo-convex pattern for light scattering formed on the surface by the concavity and convexity of the concavo-convex forming layer is formed on the upper layer side of the upper layer film. A method for manufacturing a thin film semiconductor device, comprising: 12. A method of manufacturing an electro-optical device using the method of manufacturing a thin film semiconductor device defined in claim 8, wherein the thin film semiconductor device is connected to a pixel electrode and the pixel electrode. An active matrix substrate in which pixel switching TFTs are formed in a matrix. On the active matrix substrate, the thin film transistors and the pixel electrodes are provided with the first photosensitive resin layer and the second photosensitive resin layer. The electro-optic material is electrically connected through the contact hole, and holds an electro-optic substance between the active matrix substrate and a counter substrate arranged to face the active matrix substrate. Device manufacturing method. 13. The method of manufacturing an electro-optical device according to claim 12, wherein the electro-optical substance is liquid crystal.