Germanium-silicon etching solution

Abstract

The invention discloses a germanium-silicon etching solution. The germanium-silicon etching liquid comprises the following components in percentage by mass: 0.1%-5% of fluoride, 5%-25% of an oxidizing agent, 0.5%-2% of an inhibitor and water. The germanium-silicon etching liquid disclosed by the invention has a good etching rate on a silicon material; and the germanium-silicon etching solution can slow down or slightly accelerate the oxidation rate of silicon and the removal rate of oxide while accelerating the oxidation rate of the silicon-germanium alloy and the removal rate of the oxide, and has a relatively high selection ratio.

Description

Technical Field

[0001] The present invention relates to a germanium-silicon etching solution. Background Art

[0002] With the reduction of the size, improvement of the speed and function of ultra-high density integrated circuits, the technology node of integrated circuits has been reduced 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 deposition materials of the sacrificial layer and the channel layer, a Si / SiGe or SiGe / Si selective etching solution is required. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of poor etching performance and low selectivity ratio of the existing germanium-silicon etching solution for the materials of the sacrificial layer and the channel layer (alternating silicon (Si) and silicon-germanium alloy (SiGe) layers) in a GAA MOSFET, and provide a germanium-silicon etching solution. The germanium-silicon etching solution of the present invention can be used in a GAA MOSFET to selectively etch and remove the sacrificial layer to form nanowires in the channel region. More specifically, it can be used to selectively accelerate the oxidation rate and oxide removal rate of the silicon-germanium alloy, while slowing down or slightly accelerating the oxidation rate and oxide removal rate of silicon 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% or 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 by mass fraction: 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] For components (1) to (8), the fluoride, the oxidant, the complexing agent, the inhibitor, the non-ionic surfactant, and water are as 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 application for 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 of the present invention can be used in GAA MOSFETs to selectively etch and remove the sacrificial layer to form nanowires in the channel region, which 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 noted 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 Etching Solution

[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 etching solution.

[0053] Table 1 Types of raw material components of germanium-silicon etching solution

[0054] Fluoride Oxidizing agent Complexing agent Inhibitor Non-ionic 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 Comparative example 1 Hydrofluoric acid Hydrogen peroxide EDTA Alanine EO-PO polymer L42 Deionized water

[0055] Table 2 Feeding amounts of raw material components of germanium-silicon etching solution

[0056]

[0057]

[0058] Table 3 Mass percentage contents of raw material components of germanium-silicon etching solution

[0059]

[0060] "The balance" in the table means, in each example, 100% minus the mass percentage of other components.

[0061] Application Examples

[0062] 1. Germanium-Silicon Etching Rate

[0063] Etching rate test sample: 4*4 cm silicon-germanium alloy (30% Ge) epitaxial wafer.

[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 to be tested for etching rate: 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 4

[0075] Table 4

[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 Comparative 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 fluoride 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 germanium-silicon etching solution, characterized in that, The described germanium-silicon etching solution comprises components with the following mass fractions: 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 each component's mass in the total mass of all components.

2. The germanium-silicon etching solution according to claim 1, characterized in that, In the described germanium-silicon etching solution, the fluoride is one or more of hydrofluoric acid, ammonium fluoride, tetramethylammonium fluoride, ammonium bifluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride, fluorosulfonic acid, fluoroboric acid, ammonium bifluoride, hexafluorosilicic acid, hexafluorosilicate, triethylamine trihydrofluoride or pyridine hydrofluoride; And / or, in the described germanium-silicon etching solution, the oxidant is one or more of hydrogen peroxide, peracetic acid, perboric acid, ammonium persulfate, nitric acid or periodic acid; And / or, in the described 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 / or, in the described germanium-silicon etching solution, the water is preferably one or more of deionized water, distilled water or ultrapure water, more preferably deionized water.

3. The germanium-silicon etching solution according to claim 2, wherein, In the described germanium-silicon etching solution, the fluoride is hydrofluoric acid; And / or, in the described germanium-silicon etching solution, the oxidant is hydrogen peroxide; And / or, in the described germanium-silicon etching solution, the inhibitor is alanine.

4. In the germanium-silicon etching solution according to claim 1, it is characterized in that, In the described germanium-silicon etching solution, the mass fraction of the fluoride is 0.1%-5%, preferably 0.1%, 1%, 2.5% or 5%; And / or, in the described germanium-silicon etching solution, the mass fraction of the oxidant is 5%-25%, preferably 5%, 10%, 15%, 20% or 25%; And / or, in the described germanium-silicon etching solution, the mass fraction of the inhibitor is 0.5%-1%, preferably 1%.

5. The germanium-silicon etching solution according to claim 1, wherein The described germanium-silicon etching solution further comprises components with the following mass fractions: 0.01%-5% of complexing agent and 0.01%-1% of non-ionic surfactant.

6. The germanium-silicon etching solution according to claim 5, wherein, In the described germanium-silicon etching solution, the mass fraction of the complexing agent is 0.5%-2%, preferably 1%; And / or, in the described germanium-silicon etching solution, the mass fraction of the non-ionic surfactant is 0.1%-1%, preferably 0.5%; And / or, in the described germanium-silicon etching solution, 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, in the germanium-silicon etching solution, 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 germanium-silicon etching solution according to claim 1, characterized in that, The germanium-silicon etching solution comprises the following components in mass fractions: 0.1%-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 germanium-silicon etching solution according to any one of claims 1-6, characterized in that The 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 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 germanium-silicon etching solution according to any one of claims 1-6, characterized in that, The germanium-silicon etching solution consists of the following components in mass fractions: 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 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 germanium-silicon etching solution according to claim 1, characterized in that, The 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.

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