Preparation method of germanium-silicon etching liquid
By preparing a silicon germanium etching solution containing fluoride, oxidant and inhibitor, the problem of poor etching performance in GAA MOSFET is solved, and high selective etching of silicon-germanium alloy is achieved, improving etching efficiency and selectivity.
Patent Information
- Application Number
- CN202311854466.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2025-07-01
AI Technical Summary
The existing silicon germanium etching fluid has poor etching performance on the sacrificial layer and channel layer in GAA MOSFETs, and has poor defects in selecting them.
A silicon germanium etching solution is prepared, containing 0.1%-5% fluoride, 5%-25% oxidant, 0.5%-2% inhibitor and water. The nanowires formed by selective etching of the sacrificial layer are removed to selectively accelerate the oxidation rate and oxide removal rate of the silicon-germanium alloy, while slowing or slightly accelerating the oxidation rate and oxide removal rate of the silicon.
High selective etching of silicon-germanium alloys in GAA MOSFETs is achieved, with a selection ratio of up to 30-45, ensuring the selectivity and efficiency of the etching process.
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Abstract
Description
Technical Field
[0001] The present invention relates to a preparation method of a germanium-silicon etching solution. Background Art
[0002] With the reduction in the size, increase in speed and function of ultra-high density integrated circuits, the technology node of integrated circuits has shrunk to below 10 nm, and the precise control of various electrical characteristics of semiconductor devices has become more challenging. Compared with the planar gate MOSFET structure, the fin field-effect transistor (FinFET) enhances the gate's control ability over the channel region by wrapping the gate around three sides of the fin-shaped channel. The GAA MOSFET is similar to the FinFET, but since the gate electrode completely surrounds the channel, it has a higher potential for electrostatic control over the channel.
[0003] In a GAA MOSFET, a typical manufacturing method for the channel region includes epitaxially growing a stack of a channel layer and a sacrificial layer (epi-stack) on top of a bulk substrate. The sacrificial layer and the channel layer are composed of two different materials (alternating silicon (Si) and silicon-germanium alloy (SiGe) layers), and then the sacrificial layer is removed by selective etching to form nanowires in the channel region. According to process requirements, in a GAA MOSFET structure, due to the different deposited materials of the sacrificial layer and the channel layer, a selective etching solution of Si / SiGe or SiGe / Si is required. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the defects that the existing germanium-silicon etching solution has poor etching performance and low selectivity ratio for the materials (alternating silicon (Si) and silicon-germanium alloy (SiGe) layers) of the sacrificial layer and the channel layer in a GAA MOSFET, and to provide a preparation method of a germanium-silicon etching solution. The germanium-silicon etching solution prepared by the preparation method of the present invention can be used to selectively etch and remove the sacrificial layer to form nanowires in the channel region in a GAA MOSFET. More specifically, it can be used to selectively accelerate the oxidation rate of the silicon-germanium alloy and the oxide removal rate, while slowing down or slightly accelerating the oxidation rate of silicon and the oxide removal rate from the alternating silicon (Si) and silicon-germanium alloy (SiGe) layers of the gate electrode.
[0005] The present invention solves the above technical problems through the following technical solutions.
[0006] The present invention provides a germanium-silicon etching solution, which comprises the following components by mass fraction: 0.1% - 5% of fluoride, 5% - 25% of oxidant, 0.5% - 2% of inhibitor and water; the sum of the components is 100%, and the mass fraction is the mass percentage of the mass of each component in the total mass of each component.
[0007] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the fluoride is a fluoride conventionally used in the art, such as one or more of compounds including hydrofluoric acid, ammonium fluoride, tetramethylammonium fluoride, ammonium bifluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride, fluorosulfonic acid, fluoboric acid, ammonium bifluoride, hexafluorosilicic acid, hexafluorosilicate, triethylamine trihydrofluoride, pyridine hydrofluoride, etc., and more preferably hydrofluoric acid.
[0008] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the mass fraction of the fluoride can be 0.1%-5% (such as 0.1%, 1%, 2.5%, 5%).
[0009] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the oxidant is an oxidant conventionally used in the art, preferably one or more of hydrogen peroxide, peracetic acid, perboric acid, ammonium persulfate, nitric acid or periodic acid, and more preferably hydrogen peroxide.
[0010] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the mass fraction of the oxidant can be 5%-25% (such as 5%, 10%, 15%, 20% or 25%).
[0011] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the inhibitor is an amino acid, preferably one or more of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine or histidine, and more preferably alanine.
[0012] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the mass fraction of the inhibitor can be 0.5%-1% (such as 1%).
[0013] In a certain embodiment of the present invention, the germanium-silicon etching solution may further include components with the following mass fractions: 0.01%-5% complexing agent, 0.01%-1% nonionic surfactant.
[0014] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the complexing agent is a complexing agent conventionally used in the art, which can be an organic acid, preferably one or more of ethylenediaminetetraacetic acid (EDTA), lactic acid, benzoic acid, glycolic acid, malonic acid, maleic acid, salicylic acid, glyceric acid, oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, malic acid, methanesulfonic acid, ethanesulfonic acid, 2-hydroxyethanesulfonic acid, tartaric acid, citric acid, citrulline, gallic acid and pyrogallic acid, and more preferably EDTA.
[0015] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the mass fraction of the complexing agent can be 0.5%-2% (for example, 1%).
[0016] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the non-ionic surfactant is a non-ionic surfactant EO-PO polymer commonly used in the art, and the EO-PO polymer is a polyoxyethylene polyoxypropylene block polymer; preferably one or more of EO-PO polymer L42, EO-PO polymer L43 or EO-PO polymer L44, and preferably EO-PO polymer L42.
[0017] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the mass fraction of the non-ionic surfactant can be 0.1%-1% (for example, 0.5%).
[0018] In a certain embodiment of the present invention, in the germanium-silicon etching solution, the water is one or more of deionized water, distilled water, pure water or ultrapure water, and preferably deionized water.
[0019] In a certain embodiment of the present invention, the germanium-silicon etching solution comprises the following components in mass fractions: 0.5%-5% hydrofluoric acid, 5%-25% hydrogen peroxide, 0.05-2% ethylenediaminetetraacetic acid, 0.01%-5% alanine, 0.1%-1% EO-PO polymer L42 and water.
[0020] In certain preferred embodiments of the present invention, the germanium-silicon etching solution comprises the following components:
[0021] (1) 0.1% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant and the balance water;
[0022] (2) 1% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant and the balance water;
[0023] (3) 2.5% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant and the balance water;
[0024] (4) 5% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant and the balance water;
[0025] (5) 1% fluoride, 5% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant and the balance water;
[0026] (6) 1% fluoride, 10% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water;
[0027] (7) 1% fluoride, 20% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water;
[0028] (8) 1% fluoride, 25% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water;
[0029] In components (1) to (8), the fluoride, the oxidant, the complexing agent, the inhibitor, the non-ionic surfactant, and water are the same as those described above.
[0030] In a certain embodiment of the present invention, the germanium-silicon etching solution preferably consists of the following components by mass fraction: 0.1% - 5% of the above-mentioned fluoride, 10% - 50% of the above-mentioned oxidant, 0.01 - 5% of the above-mentioned complexing agent, 0.01 - 5% of the above-mentioned inhibitor, 0.01 - 1% of the above-mentioned non-ionic surfactant, and the balance of the above-mentioned water.
[0031] In certain preferred embodiments of the present invention, the germanium-silicon etching solution consists of the following components:
[0032] (1) 0.1% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water;
[0033] (2) 1% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water;
[0034] (3) 2.5% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water;
[0035] (4) 5% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water;
[0036] (5) 1% hydrofluoric acid, 5% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water;
[0037] (6) 1% hydrofluoric acid, 10% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water;
[0038] (7) 1% hydrofluoric acid, 20% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water;
[0039] (8) 1% hydrofluoric acid, 25% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water.
[0040] The present invention also provides a preparation method of the above-mentioned germanium-silicon etching solution, which includes the following steps: mixing the components of the germanium-silicon etching solution to obtain the germanium-silicon etching solution.
[0041] In a certain embodiment of the present invention, the temperature of the preparation method is room temperature.
[0042] The present invention also provides an application of the above-mentioned germanium-silicon etching solution in selectively etching the sacrificial layer in a GAA MOSFET structure.
[0043] In a certain embodiment of the present invention, the application can selectively accelerate the oxidation rate of the silicon-germanium alloy and the oxide removal rate, while slowing down or slightly accelerating the oxidation rate of silicon and the oxide removal rate; it has a high selectivity ratio for etching silicon-germanium alloy / Si.
[0044] In a certain embodiment of the present invention, the selective etching ratio of the silicon-germanium alloy / Si during the etching process can be 30 - 45, such as 35 - 39; preferably 36, 37, 38, 39.
[0045] On the basis of not violating the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.
[0046] The reagents and raw materials used in the present invention are all commercially available. Among them, the EO-PO polymer L42 is purchased from Nantong Jinlai Chemical Co., Ltd.
[0047] The positive and progressive effects of the present invention are as follows: The germanium-silicon etching solution prepared by the present invention can be used in GAA MOSFETs to selectively etch and remove the sacrificial layer to form nanowires in the channel region, and can selectively accelerate the oxidation rate of the silicon-germanium alloy and the oxide removal rate; at the same time, slow down or slightly accelerate the oxidation rate of silicon and the oxide removal rate; it has a high selectivity ratio for etching silicon-germanium alloy / Si. Detailed Embodiments
[0048] The present invention will be further illustrated below by way of examples, but the present invention is not limited to the scope of the examples described herein. The experimental methods without specific conditions mentioned in the following examples are carried out according to conventional methods and conditions, or selected according to the product specifications.
[0049] Preparation Examples 1-8 and Comparative Example 1
[0050] Preparation of Germanium-Silicon Etchant
[0051] Preparation raw materials: 40 wt% hydrofluoric acid, 35% hydrogen peroxide, EDTA, alanine, EO-PO polymer L42, deionized water.
[0052] At room temperature, according to the feeding amounts in Table 2, add the inhibitor, non-ionic surfactant and deionized water into a container, and then slowly add the diluted hydrofluoric acid aqueous solution (10%) and 35% hydrogen peroxide in sequence, and stir mechanically until evenly mixed to obtain the germanium-silicon etchant.
[0053] Table 1 Types of raw material components of germanium-silicon etchant
[0054] Fluoride Oxidizing agent Complexing agent Inhibitor Nonionic surfactant Water 1 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water 2 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water 3 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water 4 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water 5 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water 6 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water 7 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water 8 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water Control example Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water
[0055] Table 2 Feeding amounts of raw material components of germanium-silicon etchant
[0056]
[0057] Table 3 Mass percentage of raw material components of germanium-silicon etchant
[0058]
[0059]
[0060] "Remainder" in the table means 100% minus the mass percentage of other components in each example.
[0061] Application Examples
[0062] 1. Germanium-Silicon Etching Rate
[0063] Etching rate test sample: Silicon-germanium alloy (30% Ge) epitaxial wafer 4*4 cm.
[0064] Etching conditions: 30 °C, stirring and soaking at 200 r / min.
[0065] Etching time: 10 minutes
[0066] Etching container: Quartz cell.
[0067] Velocity measurement method: Use a thin film thickness measurement device (NANO VIEW, SEMG-1000) to measure the thickness of the sample to be tested before and after etching. The etching rate is calculated by dividing the difference between the initial thickness and the thickness after etching by the etching time (in minutes). The selectivity ratio represents the ratio of the germanium-silicon etching rate (SiGe E / R) to the silicon etching rate (Si E / R). The thickness is measured by an ellipsometer, model (J.A.Woollam spectroscopic ellipsometer Theta-SE)
[0068] 2. Si etching rate
[0069] Sample for etching rate detection: Silicon wafer 4*4 cm
[0070] Etching conditions: 30°C, stirring and soaking at 200 r / min
[0071] Etching time: 1 hour
[0072] Etching container: Quartz cell
[0073] Velocity measurement method: Use a thin film thickness measurement device (NANO VIEW, SEMG-1000) to measure the thickness of the sample to be tested before and after etching. The etching rate is calculated by dividing the difference between the initial thickness and the thickness after etching by the etching time (in minutes). The selectivity ratio represents the ratio of the germanium-silicon etching rate (SiGe E / R) to the silicon etching rate (Si E / R). The thickness is measured by an ellipsometer, model (J.A.Woollam spectroscopic ellipsometer Theta-SE)
[0074] The etching rates of the germanium-silicon etching solutions of Examples 1-8 and Comparative Example 1 are shown in Table 3
[0075] Table 3
[0076] SiGe E / R (A / min) Si E / R (A / min) Selectivity ratio 1 63 1.7 37 2 66 1.8 37 3 68 1.8 38 4 67 1.7 39 5 71 1.9 37 6 69 1.8 38 7 69 1.9 36 8 70 1.8 39 Control example 1 95 3.5 27
[0077] As can be seen from Table 3, the germanium-silicon etching solution of the present invention combines hydrogen peroxide and fluoride, which not only ensures the etching rate but also has a high selectivity ratio. During the wet etching process of silicon-germanium alloy and Si, the oxidant first oxidizes the silicon-germanium alloy and Si, and then the fluorine source removes these oxides. The inhibitor can accelerate the oxidation rate of the silicon-germanium alloy and the oxide removal rate, slow down or slightly accelerate the oxidation rate of Si and the oxide removal rate, and the inhibitor is a weak oxidant, which has a stronger oxidation effect on the silicon-germanium alloy than on Si, which further increases the selectivity for the silicon-germanium alloy
Claims
1. A preparation method of a germanium-silicon etching solution, characterized in that, It includes the following steps: Mix the following components to obtain a germanium-silicon etching solution; the germanium-silicon etching solution includes components with the following mass fractions: 0.1%-5% fluoride, 5%-25% oxidant, 0.5%-2% inhibitor, and water; the sum of the components is 100%, and the mass fraction is the mass percentage of each component's mass in the total mass of all components.
2. The preparation method of the germanium-silicon etching solution according to claim 1, wherein The temperature of the mixing is room temperature.
3. The preparation method of the germanium-silicon etching solution according to claim 1, characterized in that, The fluoride is one or more of hydrofluoric acid, ammonium fluoride, tetramethylammonium fluoride, ammonium bifluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride, fluorosulfonic acid, fluoboric acid, ammonium bifluoride, hexafluorosilicic acid, hexafluorosilicate, triethylamine trihydrofluoride, or pyridine hydrofluoride, preferably hydrofluoric acid; And / or, the oxidant is one or more of hydrogen peroxide, peracetic acid, perboric acid, ammonium persulfate, nitric acid, or periodic acid, preferably hydrogen peroxide; And / or, the inhibitor is an amino acid, preferably one or more of glycine, alanine, valine, leucine, isoleucine, methionine, proline, tryptophan, serine, tyrosine, cysteine, phenylalanine, asparagine, glutamine, threonine, aspartic acid, glutamic acid, lysine, arginine, or histidine, preferably alanine; And / or, the water is preferably one or more of deionized water, distilled water, or ultrapure water, more preferably deionized water.
4. The preparation method of the germanium-silicon etching solution according to claim 1, characterized in that The mass fraction of the fluoride is 0.1%-5%, preferably 0.1%, 1%, 2.5%, or 5%; And / or, the mass fraction of the oxidant is 5%-25%, preferably 5%, 10%, 15%, 20%, or 25%; And / or, the mass fraction of the inhibitor is 0.5%-1%, preferably 1%.
5. The preparation method of the germanium-silicon etching solution according to claim 1, characterized in that, The germanium-silicon etching solution may further include components with the following mass fractions: 0.01%-5% complexing agent and 0.01%-1% non-ionic surfactant.
6. The preparation method of the germanium-silicon etching solution according to claim 5, characterized in that, The mass fraction of the complexing agent is 0.5%-2%, preferably 1%; And / or, the mass fraction of the non-ionic surfactant is 0.1%-1%, preferably 0.5%; And / or, the complexing agent is preferably one or more of ethylenediaminetetraacetic acid, lactic acid, benzoic acid, glycolic acid, malonic acid, maleic acid, salicylic acid, glyceric acid, oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, malic acid, methanesulfonic acid, ethanesulfonic acid, hydroxyethanesulfonic acid, tartaric acid, citric acid, citrulline, gallic acid, or pyrogallic acid, more preferably ethylenediaminetetraacetic acid; And / or, the non-ionic surfactant is preferably a polyoxyethylene-polyoxypropylene block polymer; more preferably one or more of EO-PO polymer L42, EO-PO polymer L43, or EO-PO polymer L44, and most preferably EO-PO polymer L42.
7. The preparation method of the germanium-silicon etching solution according to claim 1, wherein The germanium-silicon etching solution includes components with the following mass fractions: 0.5%-5% hydrofluoric acid, 5%-25% hydrogen peroxide, 0.05-2% ethylenediaminetetraacetic acid, 0.01-5% alanine, 0.1-1% EO-PO polymer L42, and water.
8. The method for preparing a germanium-silicon etching solution according to any one of claims 1-6, characterized in that, The described germanium-silicon etching solution comprises any one of the following components: (1) 0.1% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; (2) 1% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; (3) 2.5% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; (4) 5% fluoride, 15% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; (5) 1% fluoride, 5% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; (6) 1% fluoride, 10% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; (7) 1% fluoride, 20% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; (8) 1% fluoride, 25% oxidant, 1% complexing agent, 1% inhibitor, 0.5% non-ionic surfactant, and the balance water; In components (1) to (8), the fluoride, the oxidant, the inhibitor, and the water are all as described in any one of claims 1-6; the complexing agent and the non-ionic surfactant are both as described in claim 6.
9. The preparation method of the germanium-silicon etching solution according to any one of claims 1-6, characterized in that, The described germanium-silicon etching solution consists of the following components by mass fraction: 0.1%-5% fluoride, 5%-25% oxidant, 0.01%-5% complexing agent, 0.01%-5% inhibitor, 0.01-1% non-ionic surfactant, and the balance water; The fluoride, the oxidant, the inhibitor, and the water are all as described in any one of claims 1-6; the complexing agent and the non-ionic surfactant are both as described in claim 6.
10. The preparation method of the germanium-silicon etching solution according to claim 1, characterized in that, The described germanium-silicon etching solution consists of the following components: (1) 0.1% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water; (2) 1% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water; (3) 2.5% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water; (4) 5% hydrofluoric acid, 15% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water; (5) 1% hydrofluoric acid, 5% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water; (6) 1% hydrofluoric acid, 10% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water; (7) 1% hydrofluoric acid, 20% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water; (8) 1% hydrofluoric acid, 25% hydrogen peroxide, 1% EDTA, 1% alanine, 0.5% EO-PO polymer L42, and the balance deionized water.