JPS60186020A - Etching method of ito - Google Patents

Abstract

PURPOSE:To form a fine pattern of an ITO by etching the ITO formed on the insulating layer of a substrate having electrode wirings made of aluminum or aluminum alloy with solution of specific temperature which contains specific amounts of sulfuric acid and ammonium sulfate. CONSTITUTION:Electrode wirings 3 made of aluminum or aluminum alloy are formed on an insulating substrate 20 as a circuit substrate 2, an interlayer insulator such as SiN and, in this case, an insulating film 4 is formed on the substrate 2, and a thin ITO film is then formed on the film 4. After this is patpterned by photoetching, it is etched, for example, with aqueous solution which contains 5-50wt% such as 10wt% of sulfuric acid and nitric acid with the liquid temperature at 50 deg.C or higher and lower than its boiling point such as 60 deg.C, thereby obtaining a patterned ITO1. In this case, even if defects 5, 6, 7 exist in the film 4, the ratio of the etching rates of the ITO and the aluminum or aluminum alloy is 15:1. Accordingly, the lower layer is not etched, and the wirings 3 made of the aluminum or aluminum alloy are not disconnected.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an etching method for etching TO, and in particular to an etching solution that enables a fine pattern of TO (nainm tin oxide, hereinafter referred to as TO). be.

[Prior art]

Devices obtained after etching the conventional process were as shown in Figures 5, 2, 8, and 4.

Fig. 1 is a partial cross-sectional view showing the wiring formed by a conventional (aCZ) based etching solution, Fig. 2 is a cutaway view taken along line A-A in Fig. 1, and Fig. 8 is a riAA' or AA'
A partial plane view showing a device etched with a conventional hydrochloric acid-based etching solution formed on a circuit board containing fL polar wires, Figure 4 is taken along line B-B in Figure 8. FIG. In the figure, (l) constitutes a polarization wiring at the terminal To. (2) is a substrate, (3j is an electrode wiring made of AI! or AI!-based alloy, (4) is an interlayer insulating film, (51,
tel and fyl are defects that occur in the interlayer insulating film (4), (5) is a pinhole defect, (6) is a foreign matter defect, and (7)
is a low density defect 0 copper is an insulating substrate.

In addition, in Fig. 1, TOIII is formed on a substrate 12) which is an insulating substrate, and in Fig. 8, electrode wiring til made of A/ or Al thread base metal is placed on the edge of the cutting board for insulation +.
Let J be a circuit board (2), and this circuit board (2)
TO (1) is formed on the interlayer breakdown 141 formed on the surface.◎ In such a barrel-formed device, etching of TO has been conventionally carried out using a hydrochloric acid-based etching solution, and then using hydrochloric acid and a valorizing solution. 2
A mixture of iron (FesCjl·5Hρ) and water at an imaginary ratio of 4:1:4 was generally used. Figure 1,
Figure 2 shows an example of etching a T film with the above-mentioned 4 thread etching bath solutions.
This is the result of forming a pattern with a width of, for example, 50 μm using photoresist or the like on a thin film with a thickness of 1000λ, and then etching it with a hydrochloric acid etching solution.

In this case, when the etch To with s' +% thickness xooo In solution, patterning is possible.

The nominal width is 30 μm as the limit, and if it is less than that, it
The possibility of connection arises. In addition, Fig. 3, Ome diagram is Al or AI! This is an example in which a TO thin film formed on a circuit board containing Aek-based alloy wiring was etched with a conventional hydrochloric acid-based etching solution.
I! After applying an interlayer insulator of SiN 4, in this case a loquat film (4), on a circuit board (2) containing a ``-Dan'' layer made of a ``-Dan'' type alloy, a To thin film (approx. x
This is the result of forming a pattern (oooffi), patterning it to a line width of, for example, 6G/Im by photo-etching, and then etching it with a conventional hydrochloric acid etching solution.

In this case, SiN, etc. used as the intercostal insulating film (4) conventionally suffers from pinhole defects (6), foreign object defects (6), and low-density defects as shown in FIG. 8 and 4 during or after film formation. (7), which is almost impossible to avoid. (2) When etching To, the conventional etching solution based on the number of layers penetrates through these defects, and the underlying electrode wiring (3) made of Al or AJ base metal is also etched. As a result, when a TO of approximately 1,000 people per thickness was just etched, the lower layer Al metal was considerably etched off and the electrode wiring of the A/thread base metal (Al) was often etched off, resulting in disconnection.

As mentioned above, in the conventional TO etching method, approximately 8
It is difficult to form a fine pattern of 0 μm or less, and if electrode wiring is formed in the lower layer using Al or Aj' base metal, this electrode wiring part is also likely to be etched, resulting in frequent disconnections. ◎ [Summary of the invention] This investigation was carried out in order to eliminate the drawbacks of the conventional method as described above. The present invention provides a method in which a fine pattern of T0 can be formed by etching with a solution containing both.

[Example of invention]

Hereinafter, one embodiment of the invention of C will be explained.

FIG. 6 is a partial plan view showing a TO wiring formed by an TO etching method according to an embodiment of the present invention;
FIG. 6 is a sectional view taken along line a-C in FIG. 5. In the figure, the substrate (2) is similar to the engineering TO1tlrie related substrate.
After forming a pattern of, for example, 6 Opm with photoresist % on the To741NI (1000λ) formed above, the solution temperature was heated to 60°C with an aqueous solution containing 10% by weight of both inkstone and nitric acid. This JJ11 case is made by etching with a thickness of about 100 OA', and the side etching of the TO is about 2 μm.
As shown in the figure, a sharp wiring pattern can be obtained. Also, the line width of the patternable work To is lo
The off-line diagram, which is possible with the pm-level housing, is A7, which was formed by the TO etching method according to one embodiment of this investigation.
Figure 8 is a cross-sectional view taken along the line D-D of the off-line diagram, in which A/or Al alloy is formed on an insulating substrate steel. An electrode wiring made of alloy (81) is provided to form a circuit board, and on this circuit board +21, an interlayer insulation film (4) of 5iN-J is applied, and then this insulation film (4) is applied. A thin film (approximately 1 ooo
Etched and patterned by keeping at ℃
+11 'i get. In this case, the defect +511 +61 (71 is between A
Even if it exists in the 8M movie (4), ■TO and AI! or A/
Since the etch rate ratio with the system alloy is 15;l,
Lower layer AI! Alternatively, the M-based alloy is not etched, and therefore, disconnection of the 4-pole wiring (3) due to the M or Al-based alloy can be prevented.

In the above example, both nitric acid and nitric acid were 1゜n<y
Etching was carried out using an aqueous solution method containing 5% to 50% nitric acid, but the solution strength may be any solution containing both 5 to 50% sulfuric acid and 5 to 50% nitric acid. 10～
A solution containing both 20 parts by weight of sulfuric acid and nitric acid is preferred. Note that if it is less than 51%, the reaction rate is slow9 and the etching time is too long. In addition, when the filtration rate exceeds 50%, sulfuric acid causes severe reaction and cannot be controlled, and nitric acid has uneven effects. In addition, the saliva temperature is 50
If it is above ℃ and below the boiling point, it is fine; if it is below 50 ℃, the reaction rate is too slow and it is not practical.
810g or B:O! A similar effect can be expected even when using two layers of /S:N. In particular, by using two layers of slo, /81N, pinhole defects (5), low density /JC
Defect (7) can be reduced, but still s
@Major Defects 6) and 9 cannot be overlooked, so using the multi-processing method of this invention is extremely effective.

〔Effect of the invention〕

As described above, according to the present invention, since the etched To formed on the insulating layer formed on the substrate is etched with a solution containing both sulfuric acid and nitric acid, it is possible to form a fine pattern of the To.

[Brief explanation of drawings]

17 is a partial plan view showing the knee T'O wiring formed using the conventional etching method, FIG. 2 is a sectional view taken along the line A-A, and FIG. FIG. 4 is a partial plan view showing a device with electrode wiring of Al or Al-based alloy formed using the etching method of TOTO, FIG. 4 is a sectional view taken along the line B-B in FIG. FIG. 6 is a partial plan view showing the TO wiring formed by the TO etching method according to an embodiment of the present invention.
The cross-sectional view along the prefecture and the off-line view are Al or A formed by the TO etching method according to an embodiment of the present invention.
I! FIG. 8 is a partial plan view illustrating a device for which metal electrode wiring is used for all the systems. +11--1 engineering TO, +21--board, +33--1 electric healing wiring, (4)-! - Insulating film In the figures, the same reference numerals indicate the same or ri corresponding parts. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 8 Procedural amendment (voluntary) Mr. Commissioner of the Japan Patent Office 1. Indication of the case Patent application No. 59-42511 3. Representative of the person making the amendment To Hitoshi Katayama Part 5, Column 6 for detailed explanation of the invention in the specification to be amended Contents of the amendment Page 8, line 1θ r S': 02/S:
Correct N J to r 5in2/SiN J. that's all

Claims (1)

[Claims] 111 TO formed on an insulator formed on a substrate
A method for etching t-TO, characterized by etching with a solution containing both sulfuric acid and nitric acid. (2) G liquid contains 5-50% by weight of sulfuric acid and 5-503! ji
% of nitric acid, and the solution temperature is 50'C or more and below the boiling point.
Etching method of E-To described in JJ. (31 substrate I'iAI! or A! The etching method of the process according to claim 1 or 2 JJl, which is characterized in that it is entirely composed of a thread base mth-#)