Etching composition and application thereof

Abstract

The invention provides an etching composition. The etching composition comprises an acid, an oxidizing agent, an organic solvent, a corrosion inhibitor and water. The invention provides a composition for removing spin-coating carbon by a wet method. The composition has good compatibility with metals, metal oxides, metal nitrides and dielectric media, can remove a spin-coating carbon layer under the condition of not damaging a bottom layer film, is high in removal rate, can be applied to a previous procedure and a subsequent procedure, is particularly used for recycling wafers, and has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the field of chemical mechanical polishing, and particularly to an etching composition and its uses. Background Art

[0002] Since the ArF lithography technology, the triple-layer process has been widely used. A typical planar printing triple-layer design includes a photoresist layer, a silicon-based anti-reflection layer, and a bottom anti-reflection coating (BARC). Due to the common phenomenon of line collapse after development in high aspect ratio patterns, continuously decreasing pattern sizes require thinner photoresist films. Therefore, it is necessary to use this triple-layer process to improve the pattern transfer performance after etching. BARC is an organic polymer solution that is spin-coated and baked at high temperature to form a carbon hard mask equivalent to the amorphous carbon film produced by the CVD process. Compared with the traditional chemical vapor deposition process, the spin process has a lower cost of ownership, fewer defects, and better alignment accuracy.

[0003] However, due to the strong stability of BARC, great challenges are faced in its removal. As the critical dimension (CD) decreases in multiple patterning steps at advanced nodes (such as 10 nm and above), the spin-coated carbon in the triple-layer technology has a cross-linked structure after high-temperature baking and has high corrosion resistance. Therefore, it is necessary to break chemical bonds to dissolve and remove the material after treatment with the composition.

[0004] After patterning on the wafer and during the wafer scrap and recycling process, it is necessary to remove the spin-coated BARC layer. The traditional technique is to etch and remove it with plasma (such as O2 or CF4). As the critical dimension (CD) continues to shrink, dry etching also faces many problems, such as etching the substrate, having limited reworkability of the wafer under dry etching, or incomplete etching. After plasma etching, usually a final wet cleaning step to remove residues is required. Currently, some research has been carried out on wet etching of BARC in the industry, but there are also many problems, such as the etching rate of BARC not being fast enough, directly stripping BARC, or damaging other layer materials on the wafer. Summary of the Invention

[0005] In order to overcome the above technical deficiencies, the purpose of the present invention is to provide an etching composition that can have good compatibility with metals, metal oxides, metal nitrides, and dielectrics, remove the spin-coated carbon layer without damaging the underlying film, and has a fast removal rate.

[0006] Specifically, the present invention discloses an etching composition, comprising: an acid, an oxidant, an organic solvent, a corrosion inhibitor, and water.

[0007] Preferably, the acid is selected from one or more of phosphoric acid, sulfuric acid, acetic acid, silicic acid, sulfonic acid, methanesulfonic acid, sulfamic acid, trifluoromethanesulfonic acid; the mass percentage content of the acid is 60 wt% - 95 wt%.

[0008] Preferably, the mass percentage content of the acid is 70 wt% - 90 wt%.

[0009] Preferably, the oxidant is selected from one or more of hydroxylamine, hydroxylamine sulfate, nitric acid, periodic acid, peracetic acid, hydrogen peroxide, ammonium persulfate, cumene hydroperoxide, tert-butyl hydroperoxide.

[0010] Preferably, the mass percentage content of the oxidant is 0.1 wt% - 10 wt%.

[0011] Preferably, the organic solvent is selected from one or more of 1,3-propanediol, ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ether, dipropylene glycol methyl ether, methyl tert-butyl ether, acetone, dimethyl sulfone, dimethyl sulfoxide, diethyl sulfoxide, diphenyl sulfoxide, sulfolane, N-methylformamide, dimethylformamide, N-methylacetamide, dimethylacetamide, 1-methyl-2-pyrrolidone, 2-pyrrolidone.

[0012] Preferably, the mass percentage content of the organic solvent is 1 wt% - 10 wt%.

[0013] Preferably, the corrosion inhibitor is selected from one or more of nitrilotriacetic acid, iminodiacetic acid, diethylenetriaminepentaacetic acid, hydroxyethyl ethylenediaminetriacetic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid.

[0014] Preferably, the mass percentage content of the corrosion inhibitor is 0.1 wt% - 5 wt%.

[0015] Preferably, it further includes a fluoride, and the fluoride is selected from one or more of hydrogen fluoride, ammonium fluoride, ammonium bifluoride, ammonium fluoroborate, fluoroboric acid, fluorosilicic acid, ammonium fluorosilicate; the mass percentage content of the fluoride is 0.01 wt% - 3 wt%.

[0016] Preferably, it further includes a surfactant, and the surfactant is an alkynol compound; the mass percentage content of the surfactant is 0% - 0.5 wt%.

[0017] The present invention also discloses a use of the etching composition as described above in any one for wet removal of spin-coated carbon.

[0018] After adopting the above technical solution, compared with the prior art, the following beneficial effects are achieved: the composition can have good compatibility with metals, metal oxides, metal nitrides and dielectrics, remove the spin-coated carbon layer without damaging the underlying film, has a fast removal rate, and can be applied in both the previous process and the subsequent process. The etching composition of the present invention is also particularly suitable for the recycling of wafers and has broad application prospects. Description of the Drawings

[0019] Figure 1 It is a SEM test picture of the surface of the wafer base layer before etching in Example 15 of the present invention;

[0020] Figure 2 It is a SEM test picture of the surface of the wafer base layer after etching in Example 15 of the present invention. Detailed Embodiments

[0021] The advantages of the present invention are further elaborated below in conjunction with the drawings and specific embodiments.

[0022] The etching compositions of Examples 1-15 and Comparative Examples 1-9 of the present invention are prepared according to the components and contents shown in Table 1, and the components can be mixed. Among them, the content unit of each compound is wt%.

[0023] Table 1 Components and Contents of the Etching Compositions of Examples 1-15 and Comparative Examples 1-9

[0024]

[0025]

[0026]

[0027] In order to further measure the performance of the above etching composition, some examples and comparative examples are selected for performance testing:

[0028] (1) The test methods for the etching rates of spin-on carbon (SOC), amorphous-Si, TiO, TiN, TEOS, and SiGe are as follows: the etching rate of SOC The etching composition liquid is placed on a mini-SWT (mini single-chip microcomputer) machine table and heated to the operating temperature (40-60 °C), and then the SOC wafer is placed therein and cleaned for 60 s. Then, the etching rate is calculated by measuring the thickness change before and after cleaning through an ellipsometer.

[0029] The etching rate of amorphous silicon or TiO or TEOS or SiGe Place the etching composition solution on a mini - SWT (mini - single - chip microcomputer) stage and heat it to the operating temperature (40°C - 60°C). Then place an Amorphous - Si or TiO or TEOS or SiGe wafer in it and wash for 5 minutes. Then measure the thickness change before and after washing by an ellipsometer to calculate the etching rate.

[0030] Etching rate of TiN Place the etching composition solution on a mini - SWT (mini - single - chip microcomputer) stage and heat it to the operating temperature (40°C - 60°C). Then place a TiN wafer in it and wash for 5 minutes. Then measure the change in the resistance value (Rs) of the wafer before and after washing by a Napson four - point probe to calculate the etching rate.

[0031] The above etching test results are listed in Table 2.

[0032] Table 2 Etching test results of Examples 1 - 15 and Comparative Examples 1 - 9

[0033]

[0034]

[0035]

[0036]

[0037] From the results of the examples and Comparative Examples 1 and 2 in Table 2, it can be seen that: The etching composition of the present invention can etch the spin - coated carbon layer at a rate of at least and has good compatibility with amorphous silicon, metal oxides, metal nitrides, silicon - germanium doped layers, and silicon oxide, showing advantages in the field of semiconductor chip manufacturing. Common hydrofluoric acid and SC1 solutions will cause the peeling of the SOC layer. From the results of Example 7 and Comparative Examples 3 and 4, and Example 15 and Comparative Example 5, it can be verified that when the acid content of the composition is too low, or when there is no oxidant, the etching of SOC will be greatly restricted, or even no etching will occur. The result of Comparative Example 6 reflects that organic solvents are necessary for the dissolution and etching of SOC. To explore the recommended use temperature of the composition of the present invention, the test results of Example 9, Comparative Example 8, and Comparative Example 9 at 40°C, 25°C, and 60°C respectively show that the etching composition of the present invention can etch SOC at 25°C to 60°C, and the temperature only affects its etching rate.

[0038] In addition, to further illustrate the etching stability of the etching composition of the present invention, under the same experimental conditions and experimental temperature, the etching rate of the etching composition solution of the present invention on spin - coated carbon at different times is shown in Table 3.

[0039] Table 3 Test Results of Example 9

[0040]

[0041]

[0042] As can be seen from the data in Table 3, the dissolution rate of the SOC layer by the etching composition of the present invention remains stable within 120 hours, indicating that the etching composition in the present invention has excellent stability.

[0043] (2) Use an X-ray photoelectron spectrometer (XPS) to test the adsorption of the composition on the wafer surface. Since the corrosion inhibitor contains N element, the adsorption of the composition on the wafer surface is judged by the content of N element before and after on the wafer surface. Test the adsorption of the wafer surface before and after etching by the etching composition of Example 15. The XPS test results are shown in Table 4.

[0044] Table 4 XPS Result Analysis of Example 15

[0045]

[0046] From the contents of N, S, and F in Table 4, it can be seen that there is no increase in the content of these elements on the SOC surface after etching with the etching composition in Example 15, indicating that no adsorption is formed on the surface. In addition, from the changes in the contents of C and Si before and after etching in the XPS results, it can also be proved that after the SOC layer is etched by the composition, the spin-coated carbon layer has been removed, exposing the underlying substrate.

[0047] (3) Observe the etching thickness of the etching composition of Example 15 of the present invention on the SOC wafer through a Hitachi SU8220 scanning electron microscope (SEM). The measured SEM images are as Figure 1 、 Figure 2 shown. Among them, Figure 1 is the SEM image of the SOC layer surface before etching, Figure 2 is the SEM image of the SOC layer surface after etching. By comparing Figure 1 、 Figure 2 it can be seen that the SOC layer on the upper layer of the substrate can be quickly dissolved and removed after being treated with the etching composition of the present invention.

[0048] In summary, the positive and progressive effects of the present invention are as follows: The present invention provides a composition for wet removal of spin-coated carbon. The composition can have good compatibility with metals, metal oxides, metal nitrides, and dielectrics, remove the spin-coated carbon layer without damaging the underlying film, has a fast removal rate, and can be applied in both the front-end process and the back-end process. The composition of the present invention is also particularly suitable for the recycling of wafers and has broad application prospects.

[0049] It should be noted that the embodiments of the present invention have better implementability and do not impose any form of limitation on the present invention. Any person skilled in the art may use the technical content disclosed above to modify or transform it into equivalent effective embodiments. However, as long as the content does not deviate from the technical solution of the present invention, any modification, equivalent change or modification made to the above embodiments based on the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. An etching composition, characterized in that, Comprising: an acid, an oxidizing agent, an organic solvent, a corrosion inhibitor, and water.

2. The etching composition according to claim 1, characterized in that the acid is selected from one or more of phosphoric acid, sulfuric acid, acetic acid, silicic acid, sulfonic acid, methanesulfonic acid, sulfamic acid, trifluoromethanesulfonic acid; the mass percentage content of the acid is 60 wt% - 95 wt%.

3. The etching composition according to claim 2, characterized in that the mass percentage content of the acid is 70 wt% - 90 wt%.

4. The etching composition according to claim 1, characterized in that the oxidizing agent is selected from one or more of hydroxylamine, hydroxylamine sulfate, nitric acid, periodic acid, peracetic acid, hydrogen peroxide, ammonium persulfate, cumene hydroperoxide, tert-butyl hydroperoxide.

5. The etching composition according to claim 1, characterized in that the mass percentage content of the oxidizing agent is 0.1 wt% - 10 wt%.

6. The etching composition according to claim 1, characterized in that the organic solvent is selected from one or more of 1,3-propanediol, ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol methyl ether acetate, diethylene glycol methyl ether, dipropylene glycol methyl ether, methyl tert-butyl ether, acetone, dimethyl sulfone, dimethyl sulfoxide, diethyl sulfoxide, diphenyl sulfoxide, sulfolane, N-methylformamide, dimethylformamide, N-methylacetamide, dimethylacetamide, 1-methyl-2-pyrrolidone, 2-pyrrolidone.

7. The etching composition according to claim 1, characterized in that the mass percentage content of the organic solvent is 1 wt% - 10 wt%.

8. The etching composition according to claim 1, characterized in that the corrosion inhibitor is selected from one or more of nitrilotriacetic acid, iminodiacetic acid, diethylenetriaminepentaacetic acid, hydroxyethyl ethylenediaminetriacetic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylenephosphonic acid, hexamethylenediaminetetramethylenephosphonic acid, ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid.

9. The etching composition according to claim 1, characterized in that the mass percentage content of the corrosion inhibitor is 0.1 wt% - 5 wt%.

10. The etching composition according to claim 1, characterized in that it further comprises a fluoride, and the fluoride is selected from one or more of hydrogen fluoride, ammonium fluoride, ammonium bifluoride, ammonium fluoroborate, fluoroboric acid, fluorosilicic acid, ammonium fluorosilicate; the mass percentage content of the fluoride is 0.01 wt% - 3 wt%.

11. The etching composition according to claim 1, characterized in that it further comprises a surfactant, and the surfactant is an alkynol compound; the mass percentage content of the surfactant is 0% - 0.5 wt%.

12. A use of the etching composition according to any one of claims 1 - 11 for wet removal of spin-coated carbon.

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