KR101403145B1 - Method of producing tft array substrate for liquid crystal display - Google Patents

Abstract

The present invention relates to a method of manufacturing a TFT array substrate for a liquid crystal display,

After forming a copper film, a copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) multi-film in the step of forming the gate electrode and the step of forming the source and drain electrodes; A process for producing a TFT array substrate for a liquid crystal display device, which comprises etching the film using nitric acid (HNO ₃ ), a compound containing a nitrogen atom and a carboxyl group, a compound containing a phosphate, and deionized water , A copper film, a copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayer film, and a method of forming a metal pattern using the etchant composition.

Copper, nitric acid, etchant, metal pattern, wiring

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a TFT array substrate for a liquid crystal display,

The present invention relates to a method of manufacturing a TFT array substrate for a liquid crystal display, an etching liquid composition used therein, and a method of forming a metal pattern using the etching liquid composition.

The process of forming a metal wiring on a substrate during the manufacture of a liquid crystal display device is usually performed by a metal film forming process such as sputtering, a photoresist coating process, a photoresist forming process in an optional region by exposure and development, And includes a cleaning process before and after the individual unit process, and the like. This etching process refers to a process of leaving a metal film in a selective region using a photoresist as a mask. Typically, dry etching using plasma or wet etching using an etching solution is used.

In a liquid crystal display device manufactured as described above, resistance of metal wiring has recently become a major concern. Since resistance is a major factor that causes RC signal delay, especially TFT-LCD (thin film transistor - liquid crystal display), it is important to increase panel size and realize high resolution.

Therefore, in order to realize a reduction in the RC delay signal which is indispensable for the enlargement of the TFT-LCD is essentially inde development of a low resistance material, that was mainly used conventionally chrome (Cr resistivity: 12.7 × 10 ^-8 Ωm), molybdenum ( (Specific resistance: 5 × 10 ^-8 Ωm), aluminum (Al resistivity: 2.65 × 10 ^-8 Ωm), and alloys thereof are difficult to be used for gate and data wiring used in a large-sized TFT LCD.

Under these circumstances, interest in copper films, one of the new low resistance metal films, is high. Copper films are known to have a lower resistance than aluminum and chrome films and have no environmental problems. On the other hand, studies on multi-metal films including a copper film are under way, and in particular, the metallic film that is exposed to light is a copper titanium film. This copper-titanium double-layer film has a known etchant and many new etchants have been disclosed. However, due to the special chemical properties of the titanium film, etching can not be performed unless fluorine ions are present.

However, if fluorine ions are contained in the etching solution, there are many elements that are etched together with the glass substrate and various silicon layers (the passivation layer made of the semiconductor layer and the silicon nitride film), thereby causing defective processes. Therefore, studies on molybdenum membranes, which are relatively weaker in acid resistance than titanium, are spreading.

Copper molybdenum films can be made with copper or molybdenum film thicknesses that are similar to or better than copper titanium films, and good processes can be achieved because fluorine ions do not need to be included in the etchant used in etching.

Korean Patent Laid-Open Publication No. 2004-0051502, which is a technique proposed by the present inventors as an etchant for a copper molybdenum film, discloses an additive comprising two kinds of additives including hydrogen peroxide water, organic acid, phosphate, and nitrogen (N) Deionized water. This etchant composition is easy to control the etch rate while etching copper and molybdenum film at the same time, has a good taper profile, good pattern linearity, low CD loss , The etching characteristics are maintained similar to the initial etching rate even when a large number of substrates are etched. Especially, since the etching has a characteristic of keeping the pH at about 2 to 4 while keeping the residue of the molybdenum film, .

However, it is known that the etching solution composition uses hydrogen peroxide as a peroxide, and hydrogen peroxide water is generally unstable due to the decomposition reaction as shown in the following reaction formula by the metal when the metal is included .

Cu + 2H ₂ O ₂ → Cu ^{2 +} + 2H ₂ O + O ₂ ↑

In addition, an etchant containing oxone as a copper film etchant has been proposed, but it has disadvantages such as instability of oxon itself and slow etching rate.

Disclosure of Invention Technical Problem [8] The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a semiconductor device which exhibits stable etching characteristics in etching a copper film, a copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) An etchant composition capable of etching a gate electrode, a gate line, a data electrode, and a data line in a batch manner, exhibiting an excellent etching profile and no etching residue, a method of forming a metal pattern using the same, and a TFT array And a method for manufacturing a substrate.

The present invention

Nitric acid (HNO _3),

A compound additive containing a nitrogen atom and a carboxyl group,

Phosphate-containing compound additive, and

Deionized water

Copper alloy film or copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayer film.

Further, according to the present invention,

Forming at least one of a copper film, a copper alloy film and a copper (or copper alloy) / molybdenum (or molybdenum alloy) multi-film on a substrate; And

A method of forming a metal pattern including a step of etching at least one of a copper film, a copper alloy film and a copper (or copper alloy) / molybdenum (or molybdenum alloy) multiple film formed in the above process using the etching composition of the present invention to provide.

In addition,

(a) forming a gate electrode on a substrate;

(b) forming a gate insulating layer on the substrate including the gate electrode;

(c) forming a semiconductor layer on the gate insulating layer;

(d) forming source and drain electrodes on the semiconductor layer; And

(e) forming a pixel electrode connected to the drain electrode

The method comprising the steps of:

In the step (a), a polysilicon film, a copper alloy film, or a copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayer film is formed and etched with the etchant composition of the present invention to form a gate electrode. (Or copper alloy) / molybdenum (or molybdenum alloy) multilayers are formed on the surface of the substrate, and the source and drain electrodes are formed by etching with the etchant composition of the present invention, A method of manufacturing a TFT array substrate is provided.

When etching the copper film, the copper alloy film or the copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayers using the etchant composition of the present invention, unlike the etchants conventionally using hydrogen peroxide as the main oxidizing agent, No etching residues are generated, and no problems such as electrical shorts, poor wiring, and reduced luminance are caused. In addition, the gate electrode, the gate wiring, the data electrode, and the data wiring can be etched in a batch, thereby simplifying the process and maximizing the process yield.

The present invention

Nitric acid (HNO _3),

A compound containing a nitrogen atom and a carboxy group,

A phosphate-containing compound, and

Deionized water

A copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayer film.

The nitric acid (HNO ₃ ) contained in the etchant composition of the present invention is a main component for etching a copper film, a copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) 1 to 25% by weight. If less than 1% by weight is included, the etching rate is too slow to cause unetch. If the etching rate is more than 25% by weight, the etching rate Is too fast to be controlled in the process.

The compound containing a nitrogen atom and a carboxyl group contained in the etching solution of the present invention is a main component for etching a copper film, a copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) And preferably 0.1 to 10% by weight of the composition. If the content of the compound containing a nitrogen atom and a carboxyl group is less than 0.1 wt%, the copper film is difficult to etch, and if it exceeds 10 wt%, the pH is lowered, And thus it is not easy to apply to the process. The proper pH at which the copper and copper alloy films can be etched is 0.5 to 4.5.

The compound containing a nitrogen atom and a carboxyl group of the present invention can be used without any particular limitation as long as it has a degree of purity for semiconductor processing and the metal impurity is not more than ppb.

Herein, the compound having a nitrogen atom and a carboxyl group is preferably water-soluble. Specifically, the compound having an amino group, an aminobutyric acid group, a glutamic acid group, a glycine series, at least one compound selected from the group consisting of iminodiacetic acid series, nitrilotriacetic acid series and sarcosine series can be used. It is preferably a iminodiacetic acid-based compound.

The phosphate-containing compound contained in the etchant of the present invention can control the etch rate of the copper film, the copper alloy film or the copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayers and reduce the seed loss of the pattern, . The role of this component is very important, and it is preferable that 0.1 to 10% by weight is included in the composition of the present invention. If it is contained in an amount of less than 0.1% by weight, the etching rate of copper may be very fast and the side etching may be increased. If the etching rate is more than 10% by weight, the etch rate of copper may be very slow. Therefore, when the content is out of the range of 0.1 to 10 wt%, it is difficult to control the etching rate, and the width of a desired pattern can not be obtained, so that there is a high probability of defects and a problem of mass production due to a small process margin .

The phosphate-containing compound is not particularly limited and various kinds can be used. Examples thereof include KH ₂ PO ₄ , K ₂ HPO ₄ , K ₃ PO ₄ , NaH ₂ PO ₄ , Na ₂ HPO ₄ and Na ₃ PO ₄ And at least one selected from the group consisting of

The deionized water contained in the etchant of the present invention can be used for semiconductor processing, preferably 18 MΩ / cm or more, and the deionized water content can be adjusted to the content of other components.

The compound containing nitric acid (HNO ₃ ), a compound containing a nitrogen atom and a carboxyl group, and a phosphate used in the present invention can be prepared by a commonly known method and preferably has a purity for semiconductor processing Do.

The etchant composition of the present invention comprises, relative to the total weight of the composition,

Nitric acid (HNO ₃₎ 1 to 25% by weight,

0.1 to 10% by weight of a compound containing a nitrogen atom and a carboxyl group,

0.1 to 10% by weight of a phosphate-containing compound, and

Deionized water 55 to 98.8 wt%

.

The etchant composition of the present invention may further comprise one or more additives known in the art to improve the etching performance. As the additive, a surfactant, a metal ion sequestering agent, and a corrosion inhibitor may be used.

Further, according to the present invention,

Forming at least one of a copper film, a copper alloy film and a copper (or copper alloy) / molybdenum (or molybdenum alloy) multi-film on a substrate; And

A method of forming a metal pattern including a step of etching at least one of a copper film, a copper alloy film and a copper (or copper alloy) / molybdenum (or molybdenum alloy) multiple film formed in the above process using the etching composition of the present invention .

The method of forming the metal pattern may be usefully used in the field of manufacturing TFT array substrates for liquid crystal displays.

In addition,

(a) forming a gate electrode on a substrate;

(b) forming a gate insulating layer on the substrate including the gate electrode;

(c) forming a semiconductor layer on the gate insulating layer;

(d) forming source and drain electrodes on the semiconductor layer; And

(e) forming a pixel electrode connected to the drain electrode

The method comprising the steps of:

In the step (a), a polysilicon film, a copper alloy film, or a copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayer film is formed and etched with the etchant composition of the present invention to form a gate electrode. (Or a copper alloy) / molybdenum (or molybdenum alloy) multilayer film is formed on the surface of the substrate, and then the source and drain electrodes are formed by etching with the etchant composition of the present invention, To a method of manufacturing a TFT array substrate.

(Or copper alloy) / molybdenum (or molybdenum alloy) multilayer film is formed on the source / drain (not shown) of the gate electrode and the data line of the gate electrode of the TFT TFT array substrate, as described in the above- (Or copper alloy) / molybdenum (or molybdenum alloy) multi-layered film is used as the source / drain wiring of the TFT TFT array substrate, Membrane. Therefore, the method of forming a metal pattern using the etching solution of the present invention can be usefully used for enlarging a TFT-LCD.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples and comparative examples are provided for illustrating the present invention, and the present invention is not limited by the following examples and comparative examples, and various modifications and changes may be made.

Example  1 to 3: Etchant  Preparation and Characterization of Compositions

(1) Preparation of composition

10 kg of an etchant containing nitric acid, iminodiacetic acid, sodium phosphate monobasic and deionized water was prepared according to the composition ratios (based on the total weight of the total composition) described in Table 1 below.

(2) Etch characteristics  exam

The test piece was obtained by depositing a copper film on a glass substrate by a sputtering method.

The etchant (Examples 1 to 3) prepared in a spray-type etching system (model name: ETCHER (TFT), manufactured by KCTech) was placed and heated to 30 ° C. and then the temperature reached 30 ± 0.1 ° C. The etching process was performed. The total etch time was 50% over etch based on end point detection (EPD). Substrate was injected and injection was started. When etching was completed, the substrate was taken out, washed with deionized water, dried using a hot air dryer, and photoresist was removed using a photoresist stripper. After cleaning and drying, the etching characteristics were evaluated using an electronic scanning microscope (SEM (Model: S-4700, manufactured by HITACHI), and the results are shown in Table 1 below. (FIG. 1) and a photograph of the surface of the substrate after the strip (FIG. 2) were respectively taken using a scanning electron microscope.

Nitric acid (HNO ₃₎ / iminodiacetic acid / sodium phosphate first / deionized water Etch characteristics Side etching
(탆) Etch residue Example 1 3.0 / 1.0 / 0.7 / 95.3 0.4 none Example 2 9.0 / 2.0 / 2.0 / 87.0 0.6 none Example 3 20.0 / 1.0 / 5.0 / 74.0 0.8 none Unit: wt%

As shown in Table 1, Fig. 1 and Fig. 2, it can be seen that the etchant composition of the example according to the present invention has excellent etching properties (see Fig. 1) and no etching residue (see Fig. 2) there was.

Comparative Example  1 to 4: Etchant  Preparation and Characterization of Compositions

The etching solutions were prepared in the same manner as in Example 1 except that the composition ratios shown in the following Table 2 were used, and etching processes were performed in the same manner, and the respective etching characteristics were evaluated and shown in Table 2 below.

Nitric acid (HNO ₃₎ / iminodiacetic acid / sodium phosphate first / deionized water Etch characteristics Side etching
(탆) Etch residue Comparative Example 1 3.0 / 1.0 / 0 / 96.0 1.7 none Comparative Example 2 9.0 / 2.0 / 0 / 89.0 2.2 none Comparative Example 3 20.0 / 1.0 / 0 / 79.0 3.1 none Comparative Example 4 0/5/3 / 92.0 No etching No etching Unit: wt%

As shown in Table 2, it is difficult to control the etching rate of the etching solutions of Comparative Examples 1 to 3 which do not contain such compounds as compared with Examples 1 to 3 containing a phosphate-containing compound, It can be seen that there is a disadvantage, and when the etching solution of Comparative Example 4 containing no nitric acid is used, it can be confirmed that the etching is not performed .

1 is a scanning electron microscope (SEM) image of a copper film etched using the etching solution composition according to Example 1 of the present invention.

2 is a scanning electron microscope (SEM) image of a surface of a substrate after etching a copper film using the etching solution composition according to Example 1 of the present invention.

Claims (11)

(a) forming a gate electrode on a substrate; (b) forming a gate insulating layer on the substrate including the gate electrode; (c) forming a semiconductor layer on the gate insulating layer; (d) forming source and drain electrodes on the semiconductor layer; And (e) forming a pixel electrode connected to the drain electrode The method comprising the steps of: In the step (a), a copper film, a copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) multi-film is formed and etched with an etchant composition to form a gate electrode. In the step (d) (Or copper alloy) / molybdenum (or molybdenum alloy) multi-layer film is formed on the surface of the substrate, and then etched with the etchant composition to form source and drain electrodes, The etchant composition comprises 1 to 25% by weight of nitric acid (HNO ₃ ), 0.1 to 10% by weight of a compound containing a nitrogen atom and a carboxy group, 0.1 to 10% by weight of a compound containing a phosphate, and deionized water 55 To 98.8% by weight based on the total weight of the liquid crystal composition. [4] The method of claim 1, wherein the compound containing a nitrogen atom and a carboxyl group is selected from the group consisting of alanine, aminobutyric acid, glutamic acid, glycine, iminodiacetic acid, , A nitrilotriacetic acid series compound, and a sarcosine series compound. The method for manufacturing a TFT array substrate for a liquid crystal display device according to claim 1, The phosphorous-containing compound according to claim 1, wherein the phosphate-containing compound is selected from the group consisting of KH ₂ PO ₄ , K ₂ HPO ₄ , K ₃ PO ₄ , NaH ₂ PO ₄ , Na ₂ HPO ₄ , and Na ₃ PO ₄ Of the total thickness of the TFT array substrate. delete With respect to the total composition weight, of nitric acid (HNO ₃₎ 1 to 25% by weight, 0.1 to 10% by weight of a compound containing a nitrogen atom and a carboxyl group, 0.1 to 10% by weight of a phosphate-containing compound, and Deionized water 55 to 98.8 wt% A copper alloy film or a copper (or copper alloy) / molybdenum (or molybdenum alloy) multilayer film. [7] The method of claim 5, wherein the compound containing a nitrogen atom and a carboxyl group is selected from the group consisting of alanine, aminobutyric acid, glutamic acid, glycine, iminodiacetic acid, A copper alloy film or a copper (or a copper alloy) / molybdenum (or a molybdenum (or a molybdenum alloy)), which is at least one selected from the group consisting of a nitrile compound, a nitrilotriacetic acid compound and a sarcosine compound. Alloy) multilayer etchant composition. The phosphorous-containing compound according to claim 5, wherein the phosphate-containing compound is selected from the group consisting of KH ₂ PO ₄ , K ₂ HPO ₄ , K ₃ PO ₄ , NaH ₂ PO ₄ , Na ₂ HPO ₄ , and Na ₃ PO ₄ (Or copper alloy) / molybdenum (or molybdenum alloy) multilayer film, wherein the copper film, copper alloy film or copper (or copper alloy) / molybdenum (or molybdenum alloy) delete A copper film, a copper alloy film, or a copper (or copper alloy) / molybdenum (or a copper alloy) film, characterized in that it further comprises at least one additive selected from the group consisting of a surfactant, a sequestering agent and a corrosion inhibitor Molybdenum alloy) multilayer etchant composition. Forming at least one of a copper film, a copper alloy film and a copper (or copper alloy) / molybdenum (or molybdenum alloy) multi-film on a substrate; And A step of etching at least one of a copper film, a copper alloy film and a copper (or copper alloy) / molybdenum (or molybdenum alloy) multi-film formed in the above process using the etching solution composition of any one of claims 5 to 7 and claim 9 ≪ / RTI > The method of forming a metal pattern according to claim 10, wherein the metal pattern is formed on a TFT array substrate for a liquid crystal display.

Images