JPS61172370A - Silicon thin-film transistor matrix and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the disconnection of a gate bus line even when there is a pin hole in the upper layer of the gate bus line by forming a film consisting of a material difficult to be dissolved to a buffer hydrofluoric acid solution while being superposed to the gate bus line. CONSTITUTION:A gate bus line 24 composed of double layers of a film 21 and a film 22 and a gate electrode 24a are formed onto a glass substrate 1, and a silicon nitride film 10 and a silicon film 11 are shaped onto the whole surface. A photo-resist film 14 is formed in order to form source-drain electrodes while holding a gate region, and a naturally generated oxide film on the silicon film 11 is removed. A buffer hydrofluoric acid solution is employed in the process. Since the gate bus line 24 and the gate electrode 24a are shaped in double layers in which the film 22 in nickel-chromium, platinum, gold, etc. is laminated on the film 21 in molybdenum, etc., the gate bus line 24 is not dissolved and disconnected even when there is a pin hole 12 in the laminate of the silicon nitride film 10 and the silicon film 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a silicon thin film transistor matrix and a method for manufacturing the same. In particular, the present invention relates to improvements in a silicon thin film transistor matrix used to drive each pixel of a panel display device that uses liquid crystal, electroluminescence, electrochromic material, etc. as a display element and is driven by an active matrix drive method, and a method for manufacturing the same.

[Conventional technology]

Each pixel of an active matrix drive type silicon thin film transistor matrix whose display elements are liquid crystal, electroluminescence, electrocomic, etc. is shown in FIG.
, (b), 2 is a gate bus line made of a film of molybdenum, titanium, tungsten, etc., and is formed on a glass substrate l. 3 is a drain bus line, which is connected to a tart bus through an interlayer insulating film 4! ! a
It is formed on the glass substrate l so as to intersect with 2.

6 is a silicon operating layer formed on the gate insulator 11*5 formed to cover the gate electrode 2a constituted by the terminal end of the gate bus line, and 7 and 8 are a drain electrode and a source electrode, respectively. These constitute a silicon thin film transistor. The drain electrode 7 is
It is connected to the drain bus line 3 via the drain connection electrode 7b and the through hole 7a, and the source electrode 8 is connected to the drive electrode 9 via the source connection electrode 8b.

Conventionally, the fabrication of a silicon thin film transistor matrix has been carried out as follows. In the reference drawings for explaining this manufacturing process, figure (a) is a plan view, and figure (b) is its AA sectional view.

Figure 3 (a), (b) A film made of molybdenum, tungsten, titanium, etc. is formed on a reference glass substrate l to a thickness of about t, ooo, and this is patterned to a width of about 30 colors m to form a gate bus. A line 2 and a gate electrode 2a are formed. At this time, gate pass line 2
There is a greater possibility that unexpected objects such as photoresist residue or other dust may be left on top.

Referring to FIGS. 4(a) and 4(b), a silicon nitride film 10 with a thickness of about 3,000 thick and a silicon film 11 with a thickness of about 3,000 thick are formed on the entire surface. This silicon nitride film 10 is formed using silane (SiH).
), ammonia (NH), and nitrogen (N2), and the silicon film 11 can be formed using silane (SiH) and hydrogen (N2).
Alternatively, it is possible to use a plasma CVD method in a mixed atmosphere with argon (Ar).

There is a high probability that pinholes will occur in the stacked body of the silicon nitride film 10 and the silicon film 11 due to the presence of unexpected objects such as the above-mentioned dust. There is a high probability that a pinhole 12 will occur.

5(a), (b) In order to form source/drain electrodes across the reference gate region, a photoresist film 13 is formed in the region corresponding to the gate electrode 2a, and the natural Remove the generated oxide film (not shown). This step can be performed using a buffered hydrofluoric acid solution, which is a mixed aqueous solution of hydrofluoric acid and ammonium fluoride. When the pinhole 12 exists, the gate bus line 2 is melted and cut in the area corresponding to the pinhole 12.
A disconnection point +2a occurs.

6(a) and (b) The entire surface of the silicon film 11 contains impurities of the same conductivity type as the impurity contained in the silicon film 11 by several hundred ppm -1% and has a thickness of 300 to 500 people. 14 and thickness 2.00
The aluminum film 15 is formed by about 0 people.

Thereafter, the photoresist film 13 is dissolved and the silicon film 14 and aluminum film 15 on the photoresist film 13 are lifted off to form an opening 13a.

After forming a photoresist mask 18 on the silicon thin film transistor region (see FIGS. 7(a) and (b)), the photoresist mask 1B is etched using a dry etching method using carbon tetrafluoride (CF4) as a reactive gas. All films other than the gate bus line 2 and the gate electrode 2a are removed from the region not covered by the silicon oxide film, and the gate insulating film 5, the active layer 6, the drain electrode 7, and the source electrode 8 are left behind. A portion of the membrane 14 is left as a contact layer).

After removing the resist mask 16 (see FIGS. 2A and 2B), a drain connection electrode 7b is formed by connecting it to the drain electrode 7, and is stretched to form an intersection area between the gate bus line 2 and the drain nozzle line. After forming the interlayer insulating film 4, the drain bus line 3 is formed so as to be connected to the drain connection electrode 7b via the through hole 7a, the drive electrode 9 is formed, the source connection electrode 8b is formed, and the drive electrode 9 and source electrode 8 are connected to complete the process.

[Problem that the invention seeks to solve]

In the method for manufacturing a silicon thin film transistor matrix according to the conventional technology described above, pinholes are likely to occur in the silicon nitride film for forming the gate insulating film and the silicon film for forming the operating layer of the transistor. If this pinhole exists, the gate bus line under the pinhole will be dissolved and disconnected during the removal process of the naturally occurring oxide film that naturally occurs on the silicon film that forms the active layer of the transistor, and the manufacturing yield will not be satisfied. The drawback is that it is not a kimono.

[Means for solving problems]

The present invention eliminates this drawback, and even if a pinhole exists in the silicon nitride film and the silicon film that forms the operating layer of the transistor, the gate bus line will not be disconnected in the subsequent process. The purpose of the present invention is to provide a silicon thin film transistor matrix and a method for manufacturing the same that can realize an excellent manufacturing yield, and the means thereof are as follows:
A plurality of gate bus lines, a plurality of drain bus lines orthogonal to the gate bus lines, and a plurality of drain bus lines provided at the intersections of the drain bus lines and the gate bus lines and connected to the gate bus lines and the drain bus lines, respectively. In a silicon thin film transistor matrix comprising a silicon thin film transistor having a gate and a drain, and a drive electrode connected to the source of the silicon thin film transistor, the gate bus line has a base metal thin film and a base metal thin film, nickel chrome, gold, or platinum. A silicon thin film transistor is formed by forming a plurality of gate bus lines on a glass substrate and a silicon thin film transistor matrix characterized by being a laminate with a thin film, and forming a silicon thin film transistor by using the end portion of the gate bus line as a gate electrode. A method for manufacturing a silicon thin film transistor matrix comprising forming a plurality of drain nozzle lines connected to the drain of a thin film transistor and perpendicular to the gate bus line, and forming a drive electrode by connecting to the source of the silicon thin film transistor. The method for manufacturing a silicon thin film transistor matrix is characterized in that the plurality of gate bus lines are formed by laminating a base metal thin film and a nickel chrome, gold, or platinum thin film.

[Effect]

The present invention focuses on the fact that the cause of gate bus wire breakage is the dissolution of base metals such as molybdenum, titanium, and tungsten by a buffered hydrofluoric acid solution that enters through pinholes that occur accidentally in the upper layer. A film made of a material that is difficult to dissolve in a buffered hydrofluoric acid solution, such as nickel chromium, platinum, or gold, is formed on top of the gate wire formed with a thin film of Even if the gate bus line is disconnected, the gate bus line will not be disconnected.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A silicon thin film transistor matrix and a method of manufacturing the same according to an embodiment of the present invention will be further described below with reference to the drawings. In the figures referred to in the description of the following steps, figure (a) is a plan view, and figure (b) is its AA sectional view.

8(a), (b) A film made of molybdenum, titanium, tungsten, etc. is formed to a thickness of about 500 mm on the reference glass substrate 1, and then a film of nickel chrome, platinum, etc. is formed to a thickness of about 500 mm. A gate bus line consisting of a double layer of a film 21 of molybdenum, titanium, tungsten, etc. and a film 22 of nickel chrome, platinum, gold, etc. is formed by forming a film made of gold, etc., and patterning this double layer to a width of about 30JL11. 24 and a gate electrode 24a are formed.

At this time, there is a high possibility that unexpected objects such as photoresist residue or other dust will remain on the gate bus line 24, just as in the case of the prior art.

Refer to Figures 9(a) and (b) A silicon nitride film with a thickness of approximately 3,000 mm is applied over the entire surface.
Then, a silicon film 11 having a thickness of about 3,000 mm is formed. The formation of this silicon nitride film IO is performed using silane (Si).
H), ammonia (NH3), and nitrogen (N2) using a plasma CVD method in a mixed atmosphere,
The silicon film 11 is formed using silane (SiH) and hydrogen (N
2) Alternatively, it is possible to use a plasma CVD method in a mixed atmosphere with Arboy (Ar).

As in the case of the prior art, pinholes 12 are likely to occur in this stack of silicon nitride film 10 and silicon film 11.

10(a), (b) To form source/drain electrodes across the reference gate region, a photoresist film 13 is formed in the region corresponding to the gate electrode 24a, and a silicon film is formed. ! A naturally occurring oxide film (not shown) naturally formed thereon is removed. This step is possible using a buffered hydrofluoric acid solution, which is a mixed aqueous solution of hydrofluoric acid and ammonium fluoride.

By the way, the gate bus 1i 124 and the gate electrode 24a are a double layer in which a film 22 of nickel chrome, platinum, gold, etc., which is not dissolved by buffered hydrofluoric acid, is laminated on a film 21 of molybdenum, etc., so if In the previous process, silicon nitride film! Even if a pinhole 12 exists in the stack of O and silicon film 11, the gate bus line 24
will not be melted and disconnected.

Referring to FIG. 11, the entire surface contains several hundred ppm to 1% of impurities of the same conductivity type as the impurities contained in the silicon film 11, and the thickness is 30 mm.
A silicon film 14 with a thickness of 0 to 500 A and an aluminum film 15 with a thickness of about 2,000 A are formed.

After that, the photoresist film 13 is dissolved and the photoresist film is completed! The silicon film 14 and aluminum film 15 on 3 are lifted off to form an opening 13a.

After forming a photoresist mask 1B on the silicon thin film transistor region (see FIGS. 12(a) and 12(b)), the photoresist mask 1B is etched using a dry etching method using carbon tetrafluoride (CF4) as a reactive gas. All films other than the gate bus line 24 and the gate electrode 24a are removed from the region not covered by the silicon film 14, and the gate insulating film 5, the active layer 6, the drain electrode 7, and the source electrode 8 are left. (a portion of the contact layer is left as a contact layer).

After removing the reference resist mask 16 shown in FIGS. 1(a) and 1(b), a drain connection electrode 7b is formed by connecting to the drain electrode 7, and then the intersection area between the gate bus line 24 and the drain bus line is formed. After forming the interlayer insulation H4, the drain bus line 3 is formed so as to be connected to the drain connection electrode 7b via the through hole 7a, the drive electrode 9 is formed, the source connection electrode 8b is formed, and the drive electrode 9 is formed. and source electrode 8 are connected to complete a silicon thin film transistor matrix.

In the silicon thin film transistor matrix manufactured by the process described above, the gate bus line is not disconnected during the process, so that the manufacturing yield is improved. According to the results of trial production, the yield, which was conventionally about 40%, was improved to 80% in the present invention.

(Effect of the invention) As explained above, according to the present invention, if.

Even if pinholes exist in the silicon nitride film and the silicon film used to form the active layer of the transistor, the gate bus line will not be disconnected in subsequent processes, achieving excellent manufacturing yields. A silicon thin film transistor matrix and a method for manufacturing the same can be provided.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a plan view of a silicon thin film transistor matrix according to an embodiment of the present invention and its A-
It is an A sectional view. FIGS. 2(a) and 2(b) are a plan view and an AA sectional view of a silicon thin film transistor matrix according to the prior art. 3(a), (b) to FIG. 7(L), (b) are a plan view of a substrate after completion of the main manufacturing process of a silicon thin film transistor matrix according to the prior art and its AA sectional view. . Figure 8 (a), (b) ~
FIGS. 12(a) and 12(b) are a plan view and a sectional view taken along line AA of the substrate after completion of the main manufacturing process of a silicon thin film transistor matrix according to an embodiment of the present invention. 1... Glass substrate, 2... Gate bus line,
2a... Fist gate electrode, 3... Drain bus line, 4... Fist/interlayer insulating film, 5... Gate insulating film, 6... Silicon operating layer, 7... Drain electrode,
7a...φ through hole, 7b...Drain connection electrode, 8...Source electrode, 8b...Source connection electrode, 9...Drive electrode, 10...Silicon nitride film, 11-...Silicon Film, 12--Pinhole, 12a/φΦ disconnection location, 13... Photoresist film, 13a*... Opening, 14... High impurity concentration silicon film, 15... Aluminum film. 16... Photoresist film, 21... Film of φ molybdenum, titanium, tungsten, etc., 22... Film of nickel chrome, platinum, gold, etc., 24. Figure 1 (a) (b) Figure 2 (a) (b) (b) Figure 4 (b) (b) Figure 8 (b) Figure 9 (b)

Claims (2)

[Claims] (1) A plurality of gate bus lines, a plurality of drain bus lines orthogonal to the gate bus lines, and the gate bus line and the drain bus line provided at the intersection of the drain bus line and the gate bus line. In a silicon thin film transistor matrix comprising a silicon thin film transistor having a gate and a drain connected to each other, and a drive electrode connected to the source of the silicon thin film transistor, the gate bus line is made of a base metal thin film, nickel chrome, gold, or , a silicon thin film transistor matrix comprising a laminate with a platinum thin film. (2) Forming multiple tree gate bus lines on a glass substrate,
A silicon thin film transistor is formed using an end portion of the gate bus line as a gate electrode, and a plurality of drain bus lines are connected to the drain of the silicon thin film transistor and orthogonal to the gate bus line, and are connected to the source of the silicon thin film transistor. A method of manufacturing a silicon thin film transistor matrix by forming a drive electrode, wherein the plurality of gate bus lines are formed by laminating a base metal thin film and a nickel chrome, gold, or platinum thin film. Method of manufacturing the matrix.