CN103814432B - Increase the engraving method of copper/molybdenum alloy film of etching solution etching consumption - Google Patents

Abstract

The present invention relates to a kind of increase method of etching consumption of copper/molybdenum alloy film of manufacturing for TFT-LCD etching solution, according to method of the present invention, in the time using copper/molybdenum alloy film to carry out etching repeatedly with etching solution, can make the low etching characteristics such as its etching speed occurring, tapering curve, etching linearity be recovered, and can increase the etching consumption of etching solution, thereby can reduce significantly the manufacturing expense of TFT-LCD etc.

Description

Etching method of copper/molybdenum alloy film with increased etchant etching amount

technical field

The invention relates to an etching method for a copper/molybdenum alloy film of a TFT-LCD, which is characterized by increasing the amount of etching liquid used for etching.

Background technique

The microcircuits of semiconductor devices and liquid crystal display devices such as TFT-LCD are formed on conductive metal films such as aluminum, aluminum alloys, copper and copper alloys or insulating films such as silicon dioxide films and silicon nitride films formed on the substrate. Apply the photoresist accurately, and then pass through the patterned film, perform light irradiation and imaging, and make the required pattern photoresist image, using dry etching or wet etching, on the metal film or insulating film under the photoresist After the pattern is displayed, it is completed by a series of photolithography processes such as stripping and removing unnecessary photoresist.

The copper alloy used for the gate and data metal wiring of large TFT-LCD has low impedance and no environmental problems compared with the aluminum chromium wiring in the conventional technology. Copper has problems such as low adhesion to glass substrates and insulating films, and is easy to diffuse into silicon oxide films. Therefore, titanium, molybdenum, etc. are usually used as the lower thin film metal.

In addition, with the increase in size of TFT-LCD, the amount of etching solution used in wet etching is increasing. In order to reduce manufacturing costs, it is imperative to develop a technology that can reduce the amount of etching solution used.

In the prior art, hydrogen peroxide is disclosed in Korean Patent Publication No. 2003-0082375, Patent Publication No. 2004-0051502, Patent Publication No. 2006-0064881, Patent Publication No. 2006-0099089, etc. A copper/molybdenum alloy etchant for the substrate, but it only describes the composition characteristics of the etchant, which cannot satisfy the aforementioned purpose.

In this regard, the present inventors found that when an etching additive or an etching auxiliary agent was added to an etching solution for copper/molybdenum alloy whose etching characteristics were lowered due to repeated etching, the etching characteristics could be maintained. , thus completing the present invention.

Contents of the invention

The object of the present invention is to provide a method that can solve the problem that the same etchant is repeatedly used in the process of etching a copper/molybdenum alloy film, resulting in low etching characteristics, and can increase the amount of etchant used for etching.

In order to realize the object of the above invention, the etching method of the copper/molybdenum alloy film of the present invention comprises: in the etching process of the copper/molybdenum alloy film, before or after the etching solution reaches the end point of etching, in the etching solution, add More than one etching additive selected from the group consisting of inorganic acid, inorganic salt, organic acid and chelating agent, or adding an etching auxiliary agent composed of said etching additive, hydrogen peroxide and water, to make the etching of the etching solution Steps for increasing dosage.

The beneficial effect of the present invention is that, according to the method of the present invention, when using the etchant for the copper/molybdenum alloy film to etch repeatedly, the low etching characteristics such as the etching speed, the taper curve, and the etching straightness can be recovered. , and can increase the etching amount of etching solution, which can significantly reduce the manufacturing cost of TFT-LCD and the like.

Description of drawings

Fig. 1 is in etching solution, dissolves the copper/molybdenum alloy powder of 5000ppm, after copper/molybdenum alloy film etching, observes the photo of section with scanning electron microscope;

2 is a photograph of a cross-section observed with a scanning electron microscope after dissolving 7000 ppm of copper/molybdenum alloy powder and etching the copper/molybdenum alloy film in Embodiment 3 of the present invention.

detailed description

The terms used in the present invention are defined below.

The term "etching liquid" used in the present invention refers to a liquid used to reduce the thickness of a copper/molybdenum alloy film used in TFT-LCD or the like, or to form a pattern.

The term "etching additive" used in the present invention refers to a component having an effect of dissolving acidified metal ions among the components used in the etching solution.

The term "etching aid" used in the present invention refers to a solution containing a substance that helps to increase the amount of etching in addition to the etching additive.

The etching solution for copper/molybdenum alloy film used in TFT-LCD consists of hydrogen peroxide used as the main acidifying agent to acidify the copper/molybdenum alloy film, and as an etching additive to dissolve the acidified copper/molybdenum alloy film into ionic form in the solution , organic and inorganic substances that stabilize dissolved copper ions, etch inhibitors that control the etching rate and form a taper curve, and hydrogen peroxide stabilizers that prevent the decomposition reaction from being promoted by ionized metals.

Among the above components, hydrogen peroxide is used as the main component to acidify copper and molybdenum, and hydrogen peroxide below the ppb standard of metal impurities with a purity for semiconductor engineering is used, and its content is 5-40% by weight of the entire composition. %.

The etching additives in the above components have the ability to dissolve acidified metal ions, and use inorganic and organic substances. Organic substances such as acetic acid, butyric acid, citric acid, glycolic acid, oxalic acid, malonic acid, valeric acid, propionic acid, tartaric acid, succinic acid, gluconic acid and other water-soluble organic acids and chelating agents with both amino and carboxylic acid groups, Such as iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, aminotrimethylenephosphonic acid, 1-hydroxyethylene-1,1-diphosphoric acid, ethylenediaminetetramethylene Phosphoric acid, diethylene triamine pentamethylene phosphoric acid, sarcosine, alanine, glutamic acid, GABA and glycine, etc. Inorganic substances such as inorganic acids such as phosphoric acid, nitric acid, sulfuric acid and hydrofluoric acid, and inorganic salts such as phosphate, nitrate, sulfate and fluoride.

The etch inhibitors in the above components are substances used to adjust the etching rate and maintain the etching profile of the copper/molybdenum alloy film at an appropriate taper angle during etching, such as pyrazole, imidazole, 1,2,4-tri Azole, tetrazole, aminotetrazole, indole, purine, pyridine, pyrimidine, pyrrole, pyrrolidone and pyrroline and other cyclic amine compounds.

Above-mentioned hydrogen peroxide stabilizer can be phosphate, ethylene glycols, cyclic amines etc.

Below the etching spray chamber of the large-scale TFT-LCD manufacturing equipment, there is an etching solution tank that can be equipped with a certain amount of etching solution. After filling a certain amount of etching solution into the etching solution tank, use the same etching solution to perform repeated etching. However, when the same etchant is used repeatedly, there is a problem that the etching characteristics are lowered, and the number of times the etchant can be etched by the etchant is reduced. The number of times the etchant can be etched by the etching solution is the amount of etching when the etching characteristics such as the etching speed, taper curve, and etching straightness do not change when the same etching solution is repeatedly etched.

Large-scale TFT-LCD manufacturing equipment uses a large amount of etching solution. In order to reduce the amount of etching solution used, it is very important to increase the amount of etching. For this, the present invention provides a method that can increase the number of times of etching, that is, increase the etching amount of etching solution.

When the same etchant is used for repeated etching, the concentration of metal ions in the etchant will increase. In the copper/molybdenum alloy film etchant using hydrogen peroxide as an acidifying agent, it is necessary to suppress the acidification reduction reaction of metal ions and promote the reaction of hydrogen peroxide decomposition, so there is a need for substances to control the interaction between metal ions and hydrogen peroxide. reaction.

The inactivation of metal ions is due to the formation of substances and chelating agents in the etching solution by metal ions, which prevents metal ions from meeting hydrogen peroxide in a free state and performing acidification and reduction reactions. Metal ions that cannot form chelating agents react with hydrogen peroxide to decompose hydrogen peroxide, and the resulting reaction heat will further promote the reaction, causing the explosion of the etching solution. Therefore, metal ion chelation is a very important process in the etchant for copper/molybdenum alloy film. The chelation of metal ions may be an inorganic substance of an etching additive, an organic acid, a chelating agent, or the like, and is preferably deactivated in combination with a chelating agent.

Etching characteristics such as metal etching rate, taper curve, and etching straightness depend on the ratio of etching additives and etching inhibitors in the etching liquid composition for copper/molybdenum alloy films. When the etching additive is more than the etching inhibitor, the etching speed is fast and the CD (critical dimension) becomes larger; when the etching additive is less than the etching inhibitor, the etching speed is slow and the taper becomes larger. When the taper exceeds a certain value, uneven metal straightness will appear, residues will occur, and defects such as spots will occur, making the product unusable. Therefore, in the process of using the etchant, the ratio of the etchant additive and the etchant inhibitor is maintained uniformly, which is closely related to the number of times the etchant can be used for the copper/molybdenum alloy film, that is, the amount of the etchant used.

When the same etching solution is used for repeated etching, the etching additive inside the etching solution can form etched and ionized metal ions and chelating agents, so that the amount of additional etching additive for etching can be continuously reduced. That is, among the etching additives in the etchant, the free etching additives involved in new etching decrease, but the etching additives used to form chelating agents increase. On the contrary, the etching inhibitor is only used in the process of controlling the etching rate to form a uniform taper angle, so even if etching is repeated, its composition hardly decreases.

Therefore, when using the same etchant to etch repeatedly to increase the metal ions in the etchant, compared with the etching additives participating in the etching, the ratio of the etching inhibitor that controls the etching rate is more, and the etching taper angle will increase, so that The increase of etching speed and the problem of etching straightness occur (as shown in Figure 1). It can be seen that the change in the ratio of the etching additive to the etching inhibitor will reduce the number of times the etching solution is used, that is, the amount used, so that the etching cannot continue.

In order to solve the above-mentioned problems, the present invention adds an etching additive that decreases due to repeated etching, and maintains the ratio of the etching additive and the etching inhibitor in the etching solution in a state where the etching characteristics can be exhibited. In order to maintain a certain metal acidifying power, in addition to the above-mentioned etching additives, the present invention also adds an etching auxiliary agent containing hydrogen peroxide and water to the etching solution, thereby increasing the amount of etching.

The invention includes: in the etching process of copper/molybdenum alloy film, before or after the etching solution reaches the end point of etching, in the etching solution, a group consisting of inorganic acid, inorganic salt, organic acid and chelating agent is added One or more etching additives selected in the above method, or adding an etching auxiliary agent composed of the etching additive, hydrogen peroxide and water to increase the etching amount of the etching solution.

In the present invention, the "etching end point" refers to the point at which etching is completed, which can be visually recognized by those skilled in the art.

The method of the present invention is applicable to the etchant for the copper/molybdenum alloy film, the composition of the etchant and the foregoing description thereof.

In the method of the present invention, the "etching additive" used refers to a substance that can form metal ions and chelate, and can be selected from the group consisting of inorganic acids, inorganic salts, organic acids and chelating agents. Specific examples of inorganic acids, inorganic salts, organic acids, and chelating agents are as described above.

In the method of the present invention, the "etching aid" used refers to an aqueous solution composed of an etching additive, hydrogen peroxide, and water. Since the etching aid contains hydrogen peroxide, it can maintain a certain acidifying power of the metal, and it is easier to add than the etching additive. The content of hydrogen peroxide is the same as the content of hydrogen peroxide in the etching solution before etching, or can be increased or decreased within the range of ±20% compared with the content of hydrogen peroxide in the etching solution.

In one embodiment of the present invention, the etching aid is composed of 5-40% by weight of hydrogen peroxide, 1-10% by weight of one or more etching additives and the rest of water, preferably deionized water.

The content of the etching additive in the etching aid is preferably higher than the content of the etching additive in the etching solution before etching. The etching aid is an additional composition added to the etching solution. Therefore, when the content of the etching additive is greater than that of the etching solution, a greater increase in the amount of etching can be achieved even if the amount of the etching aid added is small.

Copper/molybdenum alloy film etchant liquid is made of hydrogen peroxide, various kinds of etching additives, etching inhibitors and hydrogen peroxide stabilizer etc., on the contrary, in the method of the present invention, used etching additive or etching auxiliary agent its composition It is more simple, especially does not use etching inhibitors with high unit price but relatively low manufacturing competitiveness, so it can improve the competitiveness of TFT-LCD manufacturing. In addition, when the same amount of etching solution is added to the etching additive or etching auxiliary agent used in the present invention, the amount of etching can be effectively increased.

In the manufacture of large TFT-LCDs, the amount of etching used to maintain the etching characteristics can be determined by measuring the concentration of ionized metal ions in the etching solution to determine the number of times the etching is repeated in the etching solution. Therefore, when the etching concentration of the etching solution reaches the predetermined etching amount (limit usage amount), add a certain amount of etching additive or etching auxiliary agent of the present invention, and then increase the concentration of etchable metal ions, and then reach the predetermined etching amount. , can repeatedly add etching additives or etching aids. This process can be repeated until the etching inhibitor in the etching solution can exhibit the etching properties. The second number is related to the etchant tank of the etching equipment and the amount of etching, and can be determined based on repeated evaluations.

In the method of the present invention, the etching additive or etching auxiliary agent can be divided or added continuously according to a certain amount, that is to say, until the etching inhibitor in the etching solution can exert its characteristics, it can be divided or added according to a certain amount. It is added continuously to increase the etching amount of etching solution.

Next, in order to describe the implementation mode adopted in the present invention in more detail, it is only an example of the present invention, and the content of the present invention is not limited thereto.

Embodiment Embodiment 1-3: the manufacture of etching auxiliary agent

Etching aids (Examples 1-3) and copper/molybdenum alloy film etching solution (reference example) were manufactured according to Table 1, and the component contents in Table 1 below are values in % by weight.

Table 1

Embodiment 1-4 and comparative example 1-2: etching evaluation

In order to evaluate the effectiveness of the method of the present invention, in the following manner, after adding the solutions of Examples 1-3 to the etching solution during etching, the etching characteristics were compared with those of the comparative examples. Specifically, copper/molybdenum alloys were deposited on After the molybdenum alloy is deposited Copper, photolithographic engineering was carried out on the above test piece, using patterned glass. Etching is carried out on equipment that can be sprayed (Mini-etcherME-001), and the reference examples in Table 1 can be used for the etching solution. During etching, the end point of etching was observed with naked eyes, and CD (critical dimension) loss, taper angle, and etching straightness of etching characteristics were observed with a scanning electron microscope (Hitachi Group, S-4800).

While adding copper/molybdenum alloy to the etchant, perform etching evaluation. When the metal concentration that can cause loss of etching properties such as CD (critical dimension) loss, taper angle, and etching straightness is 5000ppm or more, add Examples 1-3 solution, copper/molybdenum alloy was additionally added, and the etching evaluation was performed to confirm the etching characteristics. For comparison, no solution was added in Comparative Example 1, and an etching solution (Reference Example 1) was added in Comparative Example 2. The measurement results are shown in Table 2.

Table 2

When the metal content at which the etching solution loses its etching properties is 5000ppm, add 10% of the solutions and etching solutions of Examples 1-3 and Reference Example, and when adding copper/molybdenum alloy, the results of etching evaluation show, as shown in the table above As mentioned above, compared with Comparative Example 1 without any addition and Comparative Example 2 with etching solution added, in Example 1-3 with addition of Example 1-3, the content of the copper/molybdenum alloy that can maintain the etching characteristics is increased. In addition, as shown in Example 4, when the solution of Example 3 is divided into two additions, the amount of etching can be further increased.

From the above results, it can be seen that when using the etching solution for copper/molybdenum alloy film, in the etching process, adding the etching auxiliary agent of the present invention in the etching solution can maintain the etching characteristics and increase the etching amount of the etching solution.

Claims (5)

1. an engraving method for copper/molybdenum alloy film, is characterized in that, comprising: in the etching of copper/molybdenum alloy filmIn engineering, when the concentration of etching solution reaches determined etching consumption, described determined etching consumption is that the limit is used useAmount, in described etching solution, separately or add continuously by hydrogen peroxide, iminodiacetic acid and water and formEtching adjuvant, make etching solution etching consumption increase step.

2. copper/molybdenum alloy film engraving method according to claim 1, is characterized in that, described etching is auxiliaryAuxiliary agent also comprises sulfuric acid.

3. copper/molybdenum alloy film engraving method according to claim 1, is characterized in that, described etching is auxiliaryAuxiliary agent also comprises glycolic.

4. copper/molybdenum alloy film engraving method according to claim 1, is characterized in that, described etching is auxiliaryAuxiliary agent is made up of hydrogen peroxide, the iminodiacetic acid of 1-10 % by weight and the water of surplus of 5-40 % by weight.

5. copper/molybdenum alloy film engraving method according to claim 1, is characterized in that, adds for erosionThe gross weight of carving liquid, content is the described etching adjuvant of 5-50 % by weight.