TWI639730B - Etching liquid composition and etching method using the same - Google Patents

Abstract

An etchant composition comprising: an oxidizing agent, the oxidizing agent is contained in an amount of 5 to 15% by weight based on the total weight of the etchant composition; and a stabilizer, based on the total weight of the etchant composition, the stabilizer The content is 5 to 20%; the azole compound is 0.005 to 0.2% based on the total weight of the etchant composition; and the amine compound is based on the total weight of the etchant composition. The content of the amine compound is 5 to 20%; and the aqueous medium is such that the etching angle is between 30 and 60°, and the problem of excessive loss of the critical dimension of the copper/molybdenum multilayer metal is avoided.

Description

Etching liquid composition and etching method using the same

The present invention relates to an etchant composition, and more particularly to an etchant composition suitable for etching a copper/molybdenum composite metal layer.

In the current semiconductor manufacturing process, the patterning process usually forms a metal layer first, and forms a patterned resist layer on the metal layer to pattern the metal layer by etching. In the etching process, the dry etch process will produce a non-volatile compound, which is easy to cause residue and is not conducive to subsequent process operations. Therefore, the wet etching process is often used in the industry. Moreover, since the types of metals to be etched due to the demand are not the same, and the degree of etching required is also different, the industry currently selects appropriate acids or oxidants, respectively. Adjust the appropriate concentration of the etchant to obtain the best etching effect.

In addition, in response to the trend of large-scale flat-panel displays, in order to reduce the impedance of the wires, to improve the speed of signal transmission and simplify the manufacturing process of the driver IC, in recent years, copper or other materials with lower resistance than aluminum have been gradually adopted. As a wire material. Furthermore, the use of copper alone as a wire material affects the product due to poor adhesion between copper and the substrate (eg, glass substrate, silicon nitride, and amorphous silicon). Yield. Therefore, chromium (Cr), aluminum (Al), titanium (Ti), and molybdenum are now commonly used. Multilayer metal of (Mo), molybdenum/aluminum (Mo/Al), titanium/aluminum (Ti/Al), copper/molybdenum (Cu/Mo) and copper/molybdenum alloy (Cu/Mo alloy) or copper The multilayer metal is used as a wire material to solve the problem of poor product yield.

However, since the etching ability of the etching liquid for different metal materials is also different, the degree of etching of each layer of the metal material in the multilayer metal to be etched may vary depending on the kind of the metal. Taking the multilayer metal of copper/molybdenum and copper/molybdenum alloy as an example, the etching effect is difficult to control due to the difference in the etching ratio of the etching solution for copper and molybdenum.

Please refer to FIG. 1 , which is an electron microscope photograph of a surface of a copper/molybdenum multilayer metal etched by a conventional etching solution, which is 80,000 times, as shown in the figure, which is a complete etching of molybdenum by a conventional etching solution. The residue of molybdenum occurs. Referring to Fig. 2, an electron micrograph of a cross section of a copper/molybdenum multilayer metal etched by a conventional etching solution is magnified 30,000 times. As shown by the arrow in the figure, the undercut of the molybdenum layer may be absent after etching.

Please refer to FIG. 3 for the structural relationship between the photoresist layer 12 after the etching treatment, the metal layer 11 and the substrate 10. In addition to the above-mentioned defects, the conventional etching liquid is more likely to produce a copper/molybdenum multilayer metal having a critical dimension loss (CD loss) L that is too large, and a taper angle θ greater than or equal to 90 degrees.

Therefore, in order to solve the aforementioned problems, Taiwan Patent No. I231275 and Taiwan Patent Publication No. 200916605 have proposed etching liquid compositions for etching a plurality of layers of copper/molybdenum and copper/molybdenum alloys. The etchant compositions are all made by adding a fluorine component (eg, hydrofluoric aicd, ammonium fluoride, sodium fluoride). (sodium fluoride), potassium fluoride, ammonium bifluoride, potassium bifluoride or sodium bifluoride, to avoid the loss of molybdenum residue.

However, in the current trend of increasing emphasis on environmental protection and industrial safety, if the use of fluorine-containing components in the process not only increases the risk of industrial safety, but also must modify the existing process equipment, and must increase the treatment of fluorine-containing wastewater. With equipment, the cost of manufacturing is virtually increased. In addition, if the fluorine-containing component in the etching liquid composition corrodes the substrate in the TFT-LCD panel material (for example, glass substrate, silicon nitride, and amorphous silicon), Causes loss of yield and other material corrosion defects after product rework.

Therefore, there is still an urgent need in the industry to develop an etchant composition which does not contain fluorine and which does not have a loss of molybdenum residue after etching and has a good oblique angle.

The present invention provides an etchant composition which does not require the addition of a fluorine-containing compound or a mineral acid, the etchant composition comprising: an oxidant having a content of 5 to 15% based on the total weight of the etchant composition; a stabilizer of 5 to 20% by weight based on the total weight of the liquid composition; an azole compound having a content of 0.005 to 0.2% based on the total weight of the composition of the etching solution; based on the total weight of the composition of the etching solution An amine compound having a content of 5 to 20%; and an aqueous medium.

In order to make the etching method of the present invention have a good etching effect, the present invention provides an etching method, comprising: providing a substrate having a metal layer; A photoresist layer is formed on the metal layer, and the photoresist layer exposes a portion of the metal layer; the metal layer is etched using the etching liquid composition of the present invention.

In the etching method of the present invention, the metal layer is etched at a temperature of 20 to 40 °C. In a preferred embodiment, the metal layer is etched at a temperature of 30 to 35 °C.

In the etching method of the present invention, the metal layer can be etched by immersion or spraying.

In a specific embodiment of the etching method of the present invention, the material of the metal layer is copper/molybdenum or the material of the metal layer is copper/molybdenum alloy.

In one embodiment of the etching method of the present invention, the substrate is a glass substrate, a germanium wafer substrate, a polyimide substrate, or an epoxy copper foil substrate.

In one embodiment of the etchant composition and etching method of the present invention, the etchant composition has a pH of between 2 and 7. In a preferred embodiment, the etchant composition has a pH between 3.5 and 4.7.

In one embodiment of the etching solution composition and etching method of the present invention, the stabilizer is selected from the group consisting of alanine, glutamic acid, glycine, and glycolic acid. ), succinic acid, cystine, asparagine, malic acid, ethylenediaminetetraacetic acid (EDTA-4H), malonic acid (Malonic) Acid), iminodiacetic acid (IDA), lactic acid, nitrilotriacetic acid (NTA), phenylurea (Phenylurea), acetanilide and phenolsulfonic acid Acid) at least one of the group consisting of. For better implementation In one example, the stabilizer is selected from the group consisting of succinic acid, cystine, malic acid, ethylenediaminetetraacetic acid (EDTA-4H), malonic acid (Malonic acid). At least one of a group consisting of lactic acid, nitrilotriacetic acid (NTA), acetanilide, and phenolsulfonic acid.

In one embodiment of the etching solution composition and etching method of the present invention, the azole compound is selected from the group consisting of 1,2,4-triazole and 3-amino-1. At least one of the group consisting of 2,4-triazole (3-Amino-1H-1, 2,4-triazole) and aminotetrazole.

In one embodiment of the etching solution composition and etching method of the present invention, the amine compound is selected from the group consisting of Monoethanolamine, Isopropanol amine, 2-amino-2-methyl-1. At least one of the group consisting of 2-amino-2-methyl-1-propanol and tetramethylazanium hydroxide.

In one embodiment of the etchant composition and etching method of the present invention, the aqueous medium is deionized water.

In the etching liquid composition and etching method of the present invention, the etching liquid composition is fluorine-free and does not contain a mineral acid.

As is known from the prior art, the etching liquid composition of the present invention does not contain fluorine and does not contain inorganic acid, thereby not only reducing the risk of industrial safety, but also reducing the cost required for the wastewater treatment process.

The etching liquid composition of the invention not only has a wide operating temperature, but also can effectively avoid molybdenum residue without adding a fluorine-containing compound and a mineral acid, and the oblique angle of the multilayer metal is ideal. The range is more effective in reducing critical size losses.

10‧‧‧Substrate

11‧‧‧metal layer

12‧‧‧Photoresist layer

L‧‧‧Key size loss

Θ‧‧‧bevel angle

Fig. 1 is an electron micrograph of a surface of a copper/molybdenum multilayer metal etched by a conventional etching solution, and an electron microscope photograph of a surface of a copper/molybdenum multilayer metal which is etched by a conventional etching solution is enlarged by 30,000 times. FIG. 3 is a schematic view showing the structure of the photoresist layer, the metal layer and the substrate after the etching process; and FIG. 4 is an electron microscope photograph of the surface of the copper/molybdenum multilayer metal etched by the etching solution of the embodiment 16 of the present invention; And Fig. 5 is an electron micrograph at a magnification of 50,000 times that of the copper/molybdenum multilayer metal etched by the etching solution of the embodiment 16 of the present invention.

The embodiments of the present invention are further described by the specific embodiments thereof, and those skilled in the art can understand the other advantages and effects of the present invention from the disclosure of the present disclosure. The embodiment of the present invention is shown below, but the present invention is not limited to these embodiments.

Meanwhile, "excluding" as used in the specification means that the content is less than 10 ppm or 0 based on the total weight of the etching liquid.

The etching liquid composition of the present invention comprises: 5 to 15% of an oxidizing agent, 5 to 20% of a stabilizer, and 0.005 to a total weight of the etching liquid composition. 0.2% azole compound, 5 to 20% amine compound, and deionized water.

In the etching liquid composition of the present invention, there is no particular limitation on the selection of the oxidizing agent. In the following examples, in the case of hydrogen peroxide, molybdenum is etched with the hydrogen peroxide and copper is oxidized to copper oxide. In the etching liquid composition of the present invention, the content of the oxidizing agent is from 5 to 15%, and if the concentration of the oxidizing agent is too low, the rate of etching is affected, and the etching is not completely performed.

In the etching liquid composition of the present invention, a compound having a chelate copper ion is selected, and a stabilizer compound which is generally suitable has a ketone group (C=O) and other lone pair electrons, and other specific examples. An amino acid such as the following: an organic acid having no nitrogen and having two carboxyl groups; an organic acid having two carboxyl groups and two groups of lone pairs of electrons at different positions in the molecule or phenylurea. An exemplary stabilizer is selected from the group consisting of alanine, glutamic acid, glycine, glycolic acid, succinic acid, cystine, Asparagine, malic acid, ethylenediaminetetraacetic acid (EDTA-4H), malonic acid, iminodiacetic acid (IDA), lactic acid ( At least one of a group consisting of lactic acid), nitrilotriacetic acid (NTA), phenylurea (Phenylurea), acetanilide, and phenolsulfonic acid for chelation etching The free copper ions in the liquid composition enhance the stability of the oxidant, reduce the rate of decomposition of oxygen, and prolong the service life of the composition of the etching solution.

In the etchant composition of the present invention, by the azole compound Suppression of side etching (especially copper side etching) that may occur in the etching process, which reduces critical dimension losses. In a specific embodiment, the azole compound is selected from the group consisting of 1,2,4-triazole, 3-amino-1,2,4-triazole (3-Amino-1H). -1,2,4-triazole) and at least one of the group consisting of aminotetrazole.

In the etchant composition of the present invention, the pH of the etchant composition is adjusted by the amine compound, and the pH of the etchant composition of the present invention is between 2 and 7, and the copper can be effectively controlled. The etching rate with molybdenum enables the bevel angle to be between 30 and 60°, and the loss of molybdenum residue can be avoided.

Further, the present invention can simplify the composition of the etching liquid, can obtain excellent results without adding a fluorine-containing compound, and the etching liquid composition of the present invention does not contain a mineral acid.

The etching method of the present invention comprises: providing a substrate having a metal layer; forming a photoresist layer on the metal layer to expose a portion of the metal layer; adjusting a temperature of the etching composition of the present invention, and etching the solution The metal layer is etched at a temperature of the composition of 20 to 40 °C.

In the etching method of the present invention, there is no particular limitation on the manner of etching the metal layer, and the metal layer may be etched by dipping or spraying.

Example Example 1 Preparation of Etching Solution Composition of the Present Invention

Dissolving 5 wt% of hydrogen peroxide, 10 wt% of glycine, 1 wt% of imine diacetic acid, 0.5 wt% of glutamic acid, 0.01 wt% of aminotetrazole and 5 wt% of monoethanolamine in deionized water In 5, the etching liquid composition of Example 1 of the present invention was obtained.

Examples 2 to 20 Preparation of etching liquid composition of the present invention

The procedure of Example 1 was repeated except that the composition shown in Table 1 was used, and the etching liquid compositions of Examples 2 to 20 were prepared in accordance with the contents shown in Table 2.

Example 21 etching method of the present invention

Forming a molybdenum metal film on the glass substrate, and forming a copper metal film on the molybdenum metal to obtain a substrate having a metal layer composed of a plurality of layers of copper/molybdenum, and forming an exposed portion of the metal on the metal layer The photoresist layer of the layer.

The temperature of the etching liquid compositions of Examples 1 to 20 was adjusted, and then the metal layer obtained by the foregoing method was etched by the etching liquid compositions of Examples 1 to 20 at the temperatures as shown in Table 2, respectively. The substrate. The etching rate of the metal layer of the substrate after etching by the etching liquid composition of the present invention was measured by a film thickness measuring instrument (KLA-Tencor, model Alpha-Step IQ Surface Profiler), and scanned electron microscope (Scanning Electron) Microscope, SEM) The substrate and metal layer appearance, metal layer bevel angle and critical dimension (CD) loss were observed, and the results are reported in Table 2. The magnification was 80,000 times by a scanning electron microscope, and the appearance of the sample substrate was visually observed to have a molybdenum residue. Evaluate as follows:

◎: Good, the substrate was good in appearance, and the surface was completely free of molybdenum.

○: Preferably, 1% or more of the substrate surface has molybdenum remaining on the total area of the predetermined etching.

△: It is acceptable that 2% or more of the surface of the substrate has molybdenum remaining on the total area of the predetermined etching.

×: Poor, 2% or more of the surface of the substrate has molybdenum remaining based on the total area of the predetermined etching.

Since the visual observation in the embodiment of the present invention also includes the appearance evaluation of the substrate, it is not recommended to delete the marks of "◎", "○", "△", and "×".

Please refer to FIG. 4 , which is an electron micrograph of the surface of the copper/molybdenum multilayer metal etched by the etching solution of the embodiment 16 of the present invention, and the etchant composition of the embodiment 16 of the present invention is taken as an example. After the etching solution composition is etched, there is no loss of molybdenum residue on the surface of the substrate. Further, as is clear from Table 2, after etching using the etching liquid compositions of Examples 1 to 20 of the present invention, the substrate was not deficient in molybdenum residue.

As shown in the results of Table 2, etching using the etching liquid compositions of Examples 1 to 20 of the present invention can effectively control the bevel angle of the multilayer metal so that the bevel angle of the etching is between 30° and 60°. . From this, it can be seen that the etching liquid composition of the present invention can maintain a relatively high level of etching rate without adding a fluorine-containing compound or a mineral acid. Further, referring to Fig. 5, an electron micrograph of a cross section of the copper/molybdenum multilayer metal etched by the etching liquid composition of the embodiment 16 of the present invention is magnified 50,000 times, and the copper/molybdenum multilayer metal etched by the etching liquid composition of the present invention is known. In the middle, the molybdenum layer does not suffer from undercut problems as described in the prior art.

Referring to Table 2, on average, the etching liquid composition of the present invention has a better operational effect between 30 ° C and 35 ° C, and does not affect the composition of the etching liquid of the present invention in an environment of 20 ° C to 40 ° C. The normal operation of the object has a wide operating temperature range. In addition to this, the etching solution composition of the present invention further controls the critical dimension loss to be in the range of only 0.5 to 1 micrometer (μm) on one side. It can be seen from the prior art that the etching liquid composition of the present invention not only has a wider operating temperature than the conventional etching liquid composition, but also effectively reduces the control key dimension loss (CD loss).

In another aspect, the etchant composition of the present invention has a pH between 2 and 7 Between, preferably between 3.5 and 4.7, it is weakly acidic, thus facilitating the stability of the oxidant, thereby avoiding the decay of the oxidant and prolonging the service life of the overall etchant composition.

In summary, the etching liquid composition of the present invention can effectively control the oblique angle of the multilayer metal without adding a fluorine-containing compound, and the absence of molybdenum residue does not occur on the substrate, and has wider operation. The temperature range can also effectively reduce the critical dimension loss. In addition, the effect of prolonging the service life of the overall etching solution composition can be achieved by adjusting the composition of the etching solution of the present invention to be weakly acidic. In addition, since the metal etching solution composition of the present invention does not contain a fluorine compound or an inorganic acid, it does not corrode the glass substrate, tantalum nitride and amorphous ruthenium, and at the same time takes product yield, safety and environmental protection, and reduces the rework The risk of a defect.

The above-described embodiments are merely illustrative of the principles of the invention and its effects, and are not intended to limit the invention. Modifications and variations of the above-described embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should be as set forth in the scope of the claims, and the technical contents disclosed in the present invention should still be obtained without affecting the effects and the objects that can be achieved by the present invention. Can cover the scope.

Claims (14)

An etchant composition for a patterning process of a metal layer of copper/molybdenum or an alloy thereof, comprising: an oxidizing agent, the oxidizing agent content being 5 to 15% based on the total weight of the etching liquid composition; The stabilizer is contained in an amount of 5 to 20% based on the total weight of the etchant composition; and the azole compound is 0.005 to 0.2 based on the total weight of the etchant composition. %; an amine compound having a content of the amine compound of 5 to 20% based on the total weight of the etching liquid composition; and an aqueous medium; wherein the etching liquid composition is fluorine-free and inorganic acid, and The pH range is between 2 and 7. The etchant composition as described in claim 1 has a pH of from 3.5 to 4.7. The etchant composition according to claim 1, wherein the stabilizer is selected from the group consisting of alanine, glutamic acid, glycine, glycolic acid, and amber. Succinic acid, cystine, asparagine, malic acid, ethylenediaminetetraacetic acid (EDTA-4H), malonic acid, Iminodiacetic acid (IDA), lactic acid, nitrilotriacetic acid (NTA), phenylurea (Phenylurea), acetamidine At least one of the group consisting of acetamine and phenolsulfonic acid. The etching solution composition according to claim 1, wherein the azole compound is selected from the group consisting of 1,2,4-triazole and 3-amino-1,2. At least one of the group consisting of 4-Amino-1H-1, 2,4-triazole and aminotetrazole. The etching solution composition according to claim 1, wherein the amine compound is selected from the group consisting of Monoethanolamine, Isopropanol amine, 2-amino-2-methyl-1- At least one of the group consisting of 2-amino-2-methyl-1-propanol and tetramethylazanium hydroxide. The etching liquid composition according to claim 1, wherein the oxidizing agent is hydrogen peroxide. The etchant composition of claim 1, wherein the aqueous medium is deionized water. An etching method comprising: forming a photoresist layer on a substrate having a metal layer, and exposing a portion of the metal layer to the photoresist layer; and using the method according to any one of claims 1 to 7 The etchant composition etches the metal layer. The etching method of claim 8, wherein the step of etching the metal layer is performed at a temperature of from 20 ° C to 40 ° C. An etching method as described in claim 8, wherein the etching The step of engraving the metal layer is done by soaking. The etching method of claim 8, wherein the step of etching the metal layer is performed by spraying. The etching method according to claim 8, wherein the material of the metal layer is copper/molybdenum (Cu/Mo). The etching method according to claim 8, wherein the material for forming the metal layer is a copper/molybdenum alloy (Cu/Mo alloy). The etching method according to claim 8, wherein the substrate is a glass substrate, a germanium wafer substrate, a polyimide substrate or an epoxy copper foil substrate.