JPH01169427A - Thin film transistor panel and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a thin film transistor panel (TPT panel) used in an active matrix display device and a method for manufacturing the same.

[Conventional technology]

In the case of high-duty drive with 200 or more scanning electrodes in liquid crystal displays (liquid crystal display devices), an active matrix drive method is mainly used, which uses a switching element arranged and added to each pixel. .

FIG. 2 is a schematic diagram of the active matrix drive type liquid crystal display 1. As shown in FIG. LCD display 1 is
On one side thereof, there is provided a TPT panel 1a in which a thin film transistor (TPT) is arranged for each pixel. This T
The FT panel 1a includes transparent pixel electrodes 5 provided for each pixel arranged in a matrix on a transparent insulating substrate 2 such as a glass substrate, and transparent pixel electrodes 5 arranged so as to intersect between these pixel electrodes 5. It consists of a running signal line (drain line) 3 and a scanning line (gate line) 4, and a TPT 6 arranged and formed for each pixel electrode 5. In addition, TPT panel 1a
A glass substrate 9 on which a transparent electrode (common electrode) 8 is formed is provided on the opposite side, and a liquid crystal display 1 is constructed by sealing a liquid crystal 7 between the TPT panel 1a and the transparent electrode 8. has been done.

FIG. 3 is a schematic plan view showing an arbitrary TPT 6 in the TPT panel la shown in FIG. 2 and the arrangement of electrodes and wiring in the vicinity thereof. As shown in Figure 3, TP
In the formation region of T6, the scanning line 4 is slightly protruded at the intersection with the signal line 3, and this protrusion is used as the gate electrode 11 of the TPT6. A part of the signal line 3 located via a contact layer (not shown) is used as the drain electrode 13 of the TPT 6, and an electrode is formed on the other side of the gate electrode 11 via a semiconductor N12 and a contact layer (not shown). This is used as the source electrode 14 of the TPT 6. Further, the pixel electrode 5 is connected to the source electrode 14 through a contact hole, and a contact metal 20 is embedded in this contact hole.

FIG. 4 (dl is an enlarged cross-sectional view taken along line AA' of the TPT 6 and its vicinity shown in FIG. 3. As shown in FIG. 4 (dl), the gate electrode 11 is formed on the insulating substrate 2. A gate insulating film 15 made of silicon oxide or silicon nitride is formed to cover the gate electrode 11 and the insulating substrate 2. Above and in the vicinity of the gate electrode 11,
Amorphous silicon (a-
3t) or the like is formed. A drain electrode 13 and a source electrode 14 are formed on the semiconductor layer 12 and above both ends of the gate electrode 11 via a contact layer 16 for ohmic contact. Further, a transparent insulating film 17 for planarization is formed to cover the gate insulating film 15, the semiconductor layer 12, the contact layer 16, the drain electrode 13, and the source electrode 14. Further, the source electrode 14 and the pixel electrode 5 are connected in a contact hole formed by etching the transparent insulation rPJ, 17, and the pixel electrode 5 is further connected to the transparent insulation film 1.
It is formed on 7. Furthermore, a contact metal film 2 for ensuring the connection between the source electrode 14 and the pixel electrode 5 is provided.
0 is formed by filling the inside of the contact hole. Then, an alignment film 21 is formed on the entire surface of the TPT matrix array configured as described above. The alignment film 21 is T
This is for aligning the long axis direction of the liquid crystal molecules of the liquid crystal 7 sealed between the FT panel Ia and the transparent electrode 8 in a predetermined direction.

Next, a method of manufacturing the conventional TPT panel 1a having the above structure will be explained.

FIGS. 4(a) to 4d) are manufacturing process diagrams of a conventional TPT panel la.

First, as shown in Figure (n), a metal film is deposited by vapor deposition, sputtering, etc., a semiconductor film, a nitride film, etc. is deposited by plasma CVD, etc., and then a transparent film such as a glass substrate is deposited by patterning by photolithography. On an insulating substrate 2, a gate electrode 11 made of chromium (Cr), molybdenum (MO), etc., a gate insulating film 15 made of silicon nitride (SiN), etc., a semiconductor layer 12 made of amorphous silicon, etc., and a high concentration impurity are formed. contact fl16 made of n° amorphous silicon containing aluminum (A
A drain electrode 13 and a source electrode 14 made of a material such as β) are formed.

Next, SOG (Spin
A transparent insulating film 17 such as an on glass film is formed to have a flat surface, and the transparent insulating film 17 on the source electrode 14 is removed by photolithography.
A contact hole 18 for connection with the source electrode 14 is formed.

Subsequently, as shown in FIG.
After forming a transparent conductive film 19 such as (in-Oxide), filling all the contact holes 18 and laminating a metal film over the entire surface of the transparent conductive film 19 by vapor deposition, sputtering, etc., Patterning is performed to fill the contact hole 18 above the source electrode 4 and form a contact metal 20.

Next, as shown in FIG. 5C, the channel region 12a between the drain electrode 13 and the source electrode 14 and the transparent conductive film 19 above the drain electrode 13 were removed by photolithography to separate the pixel electrodes 5 into individual parts. Thereafter, as shown in +d) of the figure, an alignment film 21 is formed over the entire surface, covering the pixel electrode 5, the contact metal 20, and the transparent insulating film 17.

Then, in order to determine the alignment direction of the liquid crystal molecules, a surface treatment is performed in which the alignment film 21 is rubbed in a certain direction with a cotton cloth or the like (rubbing treatment).

Then, the TPT panel 1a manufactured as described above
When a liquid crystal 7 is sealed between a transparent electrode 8 and a glass substrate 9 on which a transparent electrode 8 is formed, liquid crystal molecules of the liquid crystal 7 are aligned in a certain direction when no electric field is applied.

[Problems with conventional technology]

By the way, when the alignment film 21 is rubbed in the above-mentioned rubbing process, static electricity is generated, and the TPT 6 may be electrically destroyed by the static electricity.

However, in the conventional TPT panel 1a, the pixel electrode 5 is already separated before the rubbing process is performed, as shown in FIG. Therefore, after the rubbing process, defective TP due to TPT destruction
It was difficult to detect T panel 1a. For this reason, the liquid crystal display 1 is manufactured using all the TPT panels 1a, regardless of whether they are good or defective, and the defective TPT panels 1a are selected for the first time in an operation test performed after the liquid crystal display 1 is manufactured.

Therefore, it is necessary to manufacture a liquid crystal display 1 even for a defective TPT matrix panel 1a, which results in wasted working time and lowers production efficiency.
The cost was also high.

[Purpose of the invention]

In view of the above-mentioned conventional problems, an object of the present invention is to provide a thin film transistor panel and a method for manufacturing the same, in which defective TPT caused by rubbing treatment can be detected during the manufacturing process of the thin film transistor panel, and the production efficiency of liquid crystal displays is improved. do.

[Key points of the invention]

In order to achieve the above object, the present invention is characterized in that an alignment film is disposed only on the pixel electrode.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1(d) is a sectional view of a TPT panel according to an embodiment of the present invention. Also, Figure 1! d) in Figure 4(d)
The same reference numerals are given to the parts having the same configuration as those of the conventional TPT panel 1a shown in FIG.

The TPT panel of the present invention, as shown in FIG. 1(d),
In the TFT panel of this embodiment, the alignment film 22 is not formed on the entire upper surface of the TPT panel unlike the alignment film 21 of the conventional TFT panel 1a, and is not formed above the gate electrode 11.

Because of this structure, there is no need to perform the process of separating and forming pixel electrodes for each pixel before performing the rubbing process as in the past, and after the rubbing process, an operation test can be performed for each TPT of the TPT panel 1a. It is now possible to do this. In other words, even after the rubbing process, the transparent conductive film has not yet been separated into pixel electrodes, so a test signal is applied from the scanning line and the signal line using a tester, etc., and the TP
All TPTs can be tested by turning on T's one by one and measuring the voltage of the signal written from the signal line at one end of the transparent conductive film (for example, an external terminal for testing). Therefore, it is possible to prevent liquid crystal displays from being manufactured using defective TPT panels, and it is possible to increase the manufacturing yield of liquid crystal displays.

A method of manufacturing the TPT matrix panel of this example configured as described above will be explained. Figure 1 (a) to (d)
) is a manufacturing process diagram of the TPT panel of this example.

As shown in Figure (a), first, on a transparent insulating substrate 2,
A gate electrode 11 made of chromium (Cr), molybdenum (Mo), etc., a gate insulating film 15 made of silicon nitride (SiN), etc., and a semiconductor layer 1 made of amorphous silicon, etc.
2. Contact layer 16 made of n0 amorphous silicon etc., drain electrode 1 made of aluminum (AN) etc.
3. Form the source electrode 14 to make the TPT 6. Furthermore, after forming a transparent insulating film 17 using a spin code method or the like to flatten the surface, a contact hole 18 for connecting the source electrode 14 and the pixel electrode is formed using a photolithography method. Note that as the transparent insulating film 17, a transparent insulating film such as polyimide, acrylic, or an insulating film (SOG) formed by coating and baking a silanol compound can be used.

Next, as shown in the same figure (bl), I To (Indiun-Tin-Ox
A transparent conductive film 19 such as IDE) and a metal film such as aluminum are successively formed, and the metal film is patterned by photolithography to form a contact metal 20.Furthermore, the transparent conductive film 19 and the contact A photosensitive alignment film 22 made of photosensitive polyimide or the like is coated on the entire surface of the substrate metal 20 to a predetermined thickness using a spin code method or the like.Next, the back side of the insulating substrate 2 is exposed to light to form the alignment film 22. After being exposed to light, etching is performed as shown in FIG. 1 (C1) to remove only the alignment film 22 above the gate electrode 11.

Subsequently, the alignment film 22 is subjected to the above-mentioned rubbing process, and after the rubbing process, it is inspected to see if there is any TPT that has been electrostatically damaged due to the static electricity generated during the rubbing process.

As shown in FIG. 3C, the transparent conductive film 19 is not separated into pixels after the rubbing process is completed, so a test signal is applied to the scanning line 4 and the signal line 3 from the probe needle using a tester. It is possible to test whether all TPTs 6 are defective by measuring the voltage value of the transparent conductive film 19 while turning on each TFT 6 one after another.

Then, as shown in FIG. 4(d), for the TFT panel with no defective TPT 6, the transparent conductive film 19 is etched using the alignment film 22 and the contact metal 20 as a mask.
The transparent conductive film 19 that is not covered with the alignment film 21 and the contact metal 20 is removed, and the pixel electrodes 5 are formed by separating each pixel electrode, thereby completing the TPT panel.

In this embodiment, since the alignment film 22 is made of an organic polymer film such as photosensitive polyimide, when patterning the alignment film 22, the gate electrode 11 is used as the alignment film for forming the pixel electrode 5. 22 and the contact metal 20 can be used as a mask, and the conventional TFT panel la
The number of masks can be reduced by one (conventional TPT)
In the panel la, one mask is required to form the pixel electrode 5 shown in FIG. 4(C)), so the manufacturing yield is high.

〔Effect of the invention〕

As explained above, according to the present invention, since the alignment film is not provided above the gate electrode, it is possible to perform an operation test on all TPTs after performing the rubbing treatment, so that a defective thin film transistor panel can be replaced with a thin film transistor. Can be found during panel manufacturing. Therefore, it is no longer necessary to manufacture liquid crystal displays using defective thin film transistor panels as in the past, and it is sufficient to manufacture liquid crystal displays using only good thin film transistor panels, thereby improving the production efficiency of liquid crystal displays. Therefore, it is possible to reduce the cost of the liquid crystal display.

[Brief explanation of the drawing]

Figures 1 (a) to (dl) are process diagrams showing the configuration and manufacturing method of a TPT panel according to an embodiment of the present invention, Figure 2 is a schematic configuration diagram of a liquid crystal display, and Figure 3 is a portion of a conventional TPT panel. The plan view and FIGS. 4A to 4D are process diagrams showing the configuration and manufacturing method of a conventional TPT panel. 2... Insulating substrate 5... Pixel electrode 11... Gate electrode , 12... Semiconductor layer, 13... Drain electrode, 14... Source electrode, 15... Gate insulating film, 17... Transparent insulating film, 22... Alignment film. Patent applicant Casio Computer Co., Ltd. Ltd. Figure 2 (a) (b) (c) (d) Section 41 (a)

Claims (4)

[Claims] (1) A plurality of thin film transistors formed on a transparent insulating substrate, a transparent insulating film that flattens the insulating substrate on which the thin film transistors are formed, and a transparent insulating film that is formed on the insulating film and A thin film transistor panel comprising: a plurality of transparent pixel electrodes connected to a source electrode of a thin film transistor; and an alignment film formed only on the plurality of pixel electrodes. (2) The thin film transistor panel according to claim 1, wherein the alignment film has photosensitivity. (3) forming a plurality of thin film transistors on a transparent insulating substrate; and after forming an insulating film on the insulating substrate on which the plurality of thin film transistors are formed, connecting it to a source electrode or a drain electrode to form the insulating film; a step of forming a transparent electrode material on the film; a step of forming an alignment film in a pixel pattern on the transparent electrode material and performing an alignment treatment on the formed alignment film; and the plurality of thin film transistors. A method for manufacturing a thin film transistor panel, comprising: performing an operation test; and separating the electrode material into individual pixel electrodes. (4) The method for manufacturing a thin film transistor panel according to claim 3, wherein the step of separating the electrode material into individual pixel electrodes is performed using the alignment film as a mask.