JPH03196021A - Matrix type display device - Google Patents

Abstract

PURPOSE:To simplify optimization of pretreatment conditions and to enhance product yield in a process by forming a second etching stopper made of a material substantially same as that of a semiconductor layer between a first etching stopper and a source-drain contact layer. CONSTITUTION:The second etching stopper 10 is formed between the first etching stopper 6 and the source-drain contact layer 7. The stopper 10 is made of a material substantially same as that of the semiconductor layer 5. In a buffered hydrofluoric acid (BHF) treatment to be executed after patterning the stoppers 6, 10 and before forming the source-drain contact layer 7, the surface of the semiconductor substrate 5 to be exposed the BHF solution is made of the same one material, thus permitting the optimization of the BHF treatment to be made easy, and the source-drain ohmic contact layer 7 to be formed with close adhesiveness improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to matrix display devices, and particularly to improvement in yield of thin film transistor (hereinafter referred to as thin film transistor C), TPT (hereinafter referred to as above) array substrates, and display devices using the same. be.

[Conventional technology]

A matrix type display device is usually constructed by a method in which a display material such as a liquid crystal is sandwiched between two opposing substrates, and a voltage is applied to the display material. At this time, pixel electrodes arranged in a matrix are provided on at least one substrate, and an active element having nonlinear characteristics such as TPT is provided for each pixel in order to selectively operate these pixels.

A conventional device of this type, disclosed in Japanese Patent Application Laid-Open No. 63-221678, is shown in FIGS. 4 to 6. FIG. 4 is a partial plan view showing a conventional matrix type display device, FIG. 5 is a sectional view taken along the line v--v in FIG. 4, and FIG. 6 is a sectional view of a device in the process of being manufactured.

In the figure, (1) is a transparent insulating substrate, (2) is a pixel electrode, (3) is a gate electrode/wiring, (4) is a gate insulating film, (II is a semiconductor layer, (6) is an etching stopper,
(7) Hasource/drain ohmic contact layer,
(8) is the source 1Ics/wiring, and (9) is the drain electrode.

This liquid crystal display device will be explained based on the manufacturing process.

First, on the cleaned transparent insulating substrate (1), ITO (Indiu
A transparent conducting w1 pancreas film such as mTin Oxide is deposited. This is processed into a desired pattern by a method such as photoetching to form the pixel 'R1 pole 121, electrode terminal, etc.

Second, a film of a high-melting point metal such as Cr is formed by sputtering or the like, and a gate electrode, wiring (3), etc. are formed by the same method. Thirdly, 810 as gate insulating film +41! YaS
iN, 1-a-8i or poli- as the semiconductor layer (5)
8! .

Then, a film of 5S02 or SiN as an etching stopper (6) is continuously formed using a plasma C method or the like. Fourth, contact holes for source/drain contacts are formed in the etching stopper (6), and after pretreatment with buffered hydrofluoric acid (BHF) solution, etc., an n"- a-8i
Deposit a film. Fifth, a contact hole is formed to connect the pixel electrode (2) and the drain electrode (9), which will be formed later. 6th AI, Ajt/Cr.

Al/Mo or At? A film of alloy etc. is formed by sputtering method etc. and patterned to form the source electrode/wiring (8)
and a drain electrode (9) is formed. As above, T
An FT array substrate is formed. A counter electrode substrate provided with a transparent conductive film, a color filter, etc. is provided opposite to this TFT array substrate, and a liquid crystal flat display is constructed by sandwiching a liquid crystal or the like between the two.

[Problem to be solved by the invention]

In the conventional matrix type display device, when forming the TFT array substrate as described above, the fourth 1-a-8! Before forming (7) into a film, the surface is pretreated with a BHF solution or the like in order to clean it. At this time, the films on the substrate surface exposed to this solution are 5iN (or Sin), which is an etching stopper (6), and 1-a-8i (or Po1i-St), which is a semiconductor layer (5).
Therefore, it is difficult to optimize the conditions when pre-treating such a substrate with a BHF solution, etc., resulting in problems such as not being able to make a good open contact or peeling off of n-a-s 1(7). There was a point.

This invention was made in order to solve the above-mentioned problems, and the surface of the substrate to be pretreated before forming the source/drain contact layer (7) is configured to be made of a single material as much as possible. The purpose is to simplify the optimization of pretreatment conditions and improve the yield of this process.

[Means to solve the problem]

The matrix type display device according to the present invention is different from the conventional first one.
This structure has a second etching stopper made of a material substantially equal to the material of the semiconductor layer and the material of [1-] between the etching stopper, the source FL, and the in-contact layer.

[Effect]

The second etching stopper in this invention is made of substantially the same material as the semiconductor layer 19, and in the BHF treatment performed after patterning the etching stopper and before forming the source/drain contact layer.
The substrate surface exposed to the BHF solution is made of a single material, which facilitates optimization of the B-layer process and improves the adhesion of the source-drain ohmic contact layer that is subsequently deposited.

〔Example〕

1 to 3 show a matrix type display device according to an embodiment of the present invention, FIG. 1 is a partial plan view of the matrix type display device, and FIG. -1 line sectional view and FIG. 3 are sectional views in the middle of manufacturing. Figures 1 to 3
In the figures, the same reference numerals as in FIGS. 4 to 6 indicate the same or corresponding parts. Furthermore, it is a Q13 Haffi 2-work soching stopper, and the manufacturing process thereof will be explained below.

First, an ITO film is formed on a transparent insulating substrate 0 by a mortar evaporation method, a sputtering method, or the like, and then patterned by a photoetching method or the like to form a pixel electrode (2), an electrode terminal, and the like. Second, a film of high-melting point metal such as Cr is formed by sputtering or the like, and patterned to form gate electrodes, wiring (3), and the like. Third, SiN as the gate insulating film (4)
Or 810! , i-*-8i which becomes the semiconductor layer (5)
or poli-8i, and SiN or 8*Ot which becomes the first etching stopper (6).

Furthermore, 1-1- as a second etching soba-GO
8i or poli-8i is continuously formed into a film by plasma vCVD method or the like. Fourth, source/drain contact holes were formed by etching the second etching hole +61. Open it to GO. After this, the n+-a-8 is pretreated with a BHF solution etc. to form the source/drain ohmic contact layer (7).
Deposit i. Fifth, a contact hole is formed to connect the pixel electrode (1) and the drain electrode (9). Sixth, a film of AI%AI/Cr, Al1No or A1 alloy is formed by a sputtering method, etc., and patterned by a photoetching method, etc. to form a source electrode/wiring (8).
and a drain electrode (9) is formed.

The TFT array substrate is formed in the manner described above.

Opposed to this TFT array substrate, a transparent conductive film, a color filter, etc. are provided, and a counter electrode substrate is provided, and a display material such as liquid crystal is sandwiched between the two to form a liquid crystal flat display.

In the case of the above structure, the n"-a-8 as the fourth source/drain ohmic contact layer (7)
During the pretreatment immediately before film formation, the substrate surface is almost completely covered with the second process sowing stopper 〇〇 and semiconductor layer (5) 1-a-81 (or po
li-8i), the preprocessing can be easily controlled and its margin widened. As a result na-8
Since the ohmic contact between i and 1-a-8i is well uniform and there is no possibility that ts''-a-8i is peeled off, a high-quality TFT array can be provided with a high yield.

In addition, each material is not limited to the above-mentioned example.

〔Effect of the invention〕

As described above, according to the present invention, the transparent insulating substrate has one
Pixel electrode, gate electrode, gate insulating film, semiconductor 71. 1st process 1st hand stopper comprising a source/drain contact layer, a thin film transistor (TF'I') array substrate on which a source electrode/wiring, and a drain electrode are placed in order, and a counter electrode substrate having a transparent electrode and a color filter; In a matrix display device in which a display material is sandwiched between a TFT array substrate and a counter electrode substrate,
By adopting a structure in which a second etching stopper made of substantially the same material as the semiconductor layer is provided between the first etching stopper and the source/drain contact layer, the source/drain contact layer can be tightly bonded. This has the effect of providing a high quality matrix type display device with improved power and improved yield.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the main parts of a TFT array substrate used in a multilayer display device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line 11 in FIG. 1, and FIG. 4 is a plan view showing the main parts of a TFT array substrate used in a conventional matrix type display device, FIG. 5 is a sectional view taken along the line V in FIG. 4, and FIG. FIG. (1) is a transparent insulating substrate, 121 is a pixel electrode, (3) is a gate electrode/wiring, (4) is a gate insulating film, and (5) is a semiconductor layer. (6) is the first etching saucer and (7) is the sauce.
Drain contact layer, (8) source electrode/wiring, (
9) Hat train 1t8i, O. is the second process sawing stopper. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A thin film transistor (TFT) array substrate, in which a pixel electrode, a gate electrode, a gate insulating film, a semiconductor layer, a first etching stopper, a source/drain contact layer, a source electrode/wiring, and a drain electrode are sequentially placed on a transparent insulating substrate; A matrix type display device comprising a counter electrode substrate having a transparent electrode and a color filter, and a display material sandwiched between the TFT array substrate and the counter electrode substrate, the first etching stopper and the source/drain contact layer. A matrix type display device characterized in that it has a structure in which a second etching stopper made of substantially the same material as the material of the semiconductor layer is provided between the layers.