Composition suitable for microelectronic device to selectively remove silicon germanium relative to silicon from silicon germanium / silicon lamination

Abstract

The invention relates to a composition suitable for a microelectronic device to selectively remove silicon germanium relative to silicon from a silicon germanium / silicon lamination and application. The composition comprises the following components in percentage by mass: 0.0001-10wt% of polyalkyleneimine, 0.0001-10wt% of a cosolvent, 0.0001-10wt% of an antioxidant and the 0.001 to 10 wt% of fluoride; 0.1 to 70 wt% of an oxidant; 0.01 to 50 wt% of a buffer composition; 0.00001 to 1 wt% of a silicon inhibitor; 0.0001 to 1 wt% of a silicon germanium etching stabilizer; 0.0001 to 20 weight percent of a defoaming agent; and the balance of water. The inventive compositions are useful for selectively removing silicon germanium relative to silicon from microelectronic devices having silicon and silicon germanium stacks thereon during fabrication of the microelectronic devices.

Description

Technical Field

[0001] The invention belongs to the field of electronic chemicals, and in particular relates to a composition suitable for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device. Background Art

[0002] With the rapid development of semiconductor technology, chip manufacturing processes are gradually moving towards the nanoscale, which poses unprecedented challenges to the performance, power consumption and stability of devices. In this context, GAA MOSFET achieves all-round control of channel charge by surrounding the channel material with the gate, significantly improving the mobility of the device, reducing power consumption, and reducing leakage current.

[0003] The GAA process is an advanced semiconductor manufacturing process, and the Si / SiGe heterostructure is a transistor structure with excellent performance used in the process. In order to achieve high performance and stability of the transistor, the size and shape of the nanowires need to be precisely controlled, and SiGe is often used as a sacrificial layer. By precisely controlling the etching process of the SiGe sacrificial layer, the size and shape of the nanowires or nanosheets can be precisely controlled. However, the application of SiGe nanolayers in the GAA process is not smooth sailing, and its etching technology has become one of the key factors restricting the improvement of device performance. The core difficulty of SiGe nanolayer etching technology lies in precisely controlling the depth, shape and uniformity of etching to ensure that the performance of the channel material is not affected. Due to the difference in etching rates between SiGe and Si, and the change in the germanium content in the SiGe alloy, the selectivity of the etching process becomes difficult to control. At the same time, in order to ensure the performance and stability of the device, the uniformity of etching is also crucial. Therefore, the purpose of SiGe nanolayer etching technology is not only to precisely control the shape and size of the channel material, but also to optimize the etching process parameters and improve the high selectivity and uniformity of etching to meet the manufacturing needs of high-performance semiconductor devices.

[0004] Therefore, there is a need in the art for an etching composition, which aims to provide a better etching process control for etching sacrificial layer SiGe, while improving the high selectivity and uniformity of SiGe nanolayer etching. Summary of the invention

[0005] Although the existing chemical wet etching technology can achieve the removal of silicon germanium to a certain extent, it is difficult to accurately control the removal rate of silicon germanium with the existing technology, and the selectivity relative to silicon is also poor. This is mainly because the chemical properties of silicon and germanium are similar, and it is difficult for traditional chemical reagents to make an accurate choice between the two. In addition, the existing technology also has great difficulties in processing complex three-dimensional structures, which can easily lead to uneven etching and affect the quality of the device. Therefore, how to develop a new, highly selective silicon germanium etching technology is an urgent problem to be solved in the current field of semiconductor manufacturing technology.

[0006] To solve the above problems, the present invention provides an etching composition suitable for selectively removing silicon germanium from a silicon germanium / silicon stack relative to silicon in a microelectronic device. The etching is performed using a specific composition, which comprises: a polyalkylene imine, a fluoride, an oxidant, a buffer composition, a silicon inhibitor, a SiGe etching stabilizer and a defoaming agent. The composition can achieve high selective etching of silicon germanium, wherein the etching selectivity of silicon germanium relative to silicon is greater than 50, preferably greater than 100, more preferably greater than 150, and most preferably greater than 200.

[0007] It has been found that the main object of the present invention is achieved by a composition for selectively etching a sacrificial layer comprising silicon germanium from under a silicon germanium / silicon stack structure in a microelectronic device, the composition comprising: (A) a polyalkylene imine selected from: Linear polyethyleneimine (PEI); Among them, the preferred PEI molecular weight is 600-7w, the more preferred molecular weight is 800-6w, and the most preferred molecular weight is 2k-2w.

[0008] Furthermore, the amount of PEI is 0.0001-10 wt%, preferably 0.0005-5 wt%, more preferably 0.001-2 wt%, and most preferably 0.01-1 wt%.

[0009] (B) One or more fluoride etchants containing fluoride anions, preferably selected from at least one of hydrofluoric acid, ammonium fluoride, ammonium bifluoride, fluoroboric acid, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride and fluorosilicates.

[0010] If the etchant is ammonium fluoride, the etchant may be about 0.001-10 wt %, preferably 0.002-5 wt %, more preferably 0.005-2 wt %, and most preferably 0.01-0.8 wt %, based on the total weight of the composition.

[0011] (C) one or more oxidants selected from peroxides, persulfates, percarbonates and mixtures thereof; including but not limited to: potassium permanganate, potassium dichromate, sodium periodate, sodium perbromate, potassium persulfate, hydrogen peroxide, peracetic acid, calcium peroxide, barium peroxide, sodium percarbonate, sodium perborate, ozone, oxygen, potassium bromate, potassium chlorate, calcium hypochlorite, potassium ferrate, permanganic acid, cerium ammonium nitrate, iodine pentoxide, lead tetroxide, selenium dioxide, antimony trioxide, manganese dioxide, chromium trioxide, vanadium pentoxide, silver oxide and combinations or mixtures thereof. Peroxides, persulfates, percarbonates and mixtures thereof, wherein the preferred oxidants are hydrogen peroxide and peracetic acid, and hydrogen peroxide is most preferred.

[0012] Further, the amount of the oxidant is about 0.1-70 wt%, preferably 1-60 wt%, more preferably 5-30 wt%, most preferably 10-20 wt%.

[0013] (D) one or more buffer compositions suitable for buffering the pH of the composition within the range of 1 to 7, selected from sodium dihydrogen phosphate-disodium hydrogen phosphate, dipotassium hydrogen phosphate-potassium dihydrogen phosphate, acetic acid-ammonium acetate, citric acid-ammonium citrate, and glycine-hydrochloric acid buffer systems, preferably acetic acid-ammonium acetate and citric acid-ammonium citrate buffer systems, and most preferably citric acid-ammonium citrate buffer system.

[0014] Furthermore, the pH of the etching composition is preferably in the range of 1 to 7, most preferably in the range of 3 to 5. Furthermore, the buffer system composition is used in an amount of 0.01-50 wt %, preferably 0.05-30 wt %, more preferably 0.1-20 wt %, and most preferably 0.5-10 wt %.

[0015] (E) One or more silicon inhibitors. It is found that by using fatty alcohol polyoxyethylene ether as a silicon inhibitor, the etching selectivity of SiGe on Si is significantly improved compared with the conventional etching composition. The present invention is selected from fatty alcohol polyoxyethylene ether having the following formula: RO-(CH2CH2O)ₙ-H, Wherein R represents a hydrocarbon group, which can be a saturated or unsaturated hydrocarbon group. n is the addition number of the polyoxyethylene group, indicating the length of the polyoxyethylene chain, which can be different integers depending on the type of compound and the production process.

[0016] These hydrocarbon groups may be straight-chain hydrocarbon groups or branched hydrocarbon groups.

[0017] Fatty alcohol polyoxyethylene ether (AEO series) includes but is not limited to: -AEO-7, R is C 1 2 -C1 6 Compounds containing coconut oil alcohol and n is about 7; -AEO-9, R is C 1 2 -C 1 4 A compound having a secondary alkyl group of alkyl and n is about 9; -AEO-10, R is C 1 2 -C 1 8 Compounds having a fatty alcohol group and n being about 10; -AEO-15 (Peregal 15), a compound wherein R is a C12-C18 fatty alcohol and n is about 15; - AEO-22, a compound wherein R is a C12-C18 fatty alcohol and n is about 22; - C12-14AEO-3, a compound in which R is a C12-C18 fatty alcohol and n is about 3; - and mixtures thereof Further, the amount of the silicon inhibitor used is 0.00001-1 wt %, preferably 0.0001-0.5 wt %, more preferably 0.0005-0.1 wt %, and most preferably 0.001-0.01 wt %.

[0018] (F) One or more SiGe etch stabilizers It was found that by using a combination of silicon inhibitors and SiGe etching stabilizers, precise control of the size and shape of the SiGe nanowire or nanosheet sacrificial layer on the Si / SiGe heterostructure can be achieved, ensuring the performance and stability of the device and guaranteeing the uniformity of etching.

[0019] -Polyacrylic acid (PAA) By using polyacrylic acid (PAA), SiGe etching in a silicon / silicon germanium stack structure has significantly increased uniformity and selectivity compared to prior art etching compositions.

[0020] Furthermore, the molecular weight of the PAA is 5000-450,0000, preferably 10,000-300,0000, and most preferably 50,000-150,000.

[0021] -Polyethylene glycol (PEG) The etching composition may optionally contain polyethylene glycol (PEG), which can further improve the etching uniformity and stability of SiGe on a-Si.

[0022] Furthermore, the PEG molecular weight is preferably a non-volatile viscous liquid with a molecular weight lower than 700, and PEG-400 is most preferred.

[0023] -Polyvinylpyrrolidone (PVP) The etching composition may optionally contain polyvinylpyrrolidone (PVP). P The uniformity of SiGe etching on Si can also be further improved.

[0024] Furthermore, the viscosity K value of the PVP is 8-100, preferably 10-40, and most preferably 12-20.

[0025] Furthermore, the SiGe etching stabilizer is used in an amount of 0.0001-1 wt %, most preferably 0.001-0.01 wt %.

[0026] (G) one or more defoaming agents selected from non-silicon defoaming agents such as fatty alcohols, fatty acids and fatty acid esters, and amides.

[0027] Furthermore, the fatty alcohol defoaming agent includes, but is not limited to, heptanol, octanol, nonanol, decanol, oleyl alcohol, coconut alcohol, ricinoleyl alcohol and mixtures thereof.

[0028] Furthermore, the fatty acid defoaming agent includes, but is not limited to, heptanoic acid, caprylic acid, nonanoic acid, capric acid, stearic acid, lauric acid, palmitic acid, oleic acid, myristic acid, arachidic acid, eicosapentaenoic acid, and mixtures thereof.

[0029] Furthermore, fatty acid ester defoamers include, but are not limited to, propylene glycol fatty acid esters, butyl alcohol fatty acid esters, hexanol fatty acid esters, hexanol fatty acid esters, fatty alcohol phosphates, stearin, ethyl oleate, ethyl laurate, polyglycerol fatty acid esters, and mixtures thereof.

[0030] Furthermore, amide defoamers include, but are not limited to, distearylethylenediamine, stearic acid fatty alcohol amide, N,N-dimethyldodecylamide, lauryl amide propyl betaine, cocamidopropyl betaine, polyamide, polyoxyethylene alkyl amide and mixtures thereof.

[0031] Furthermore, the defoaming agent is used in an amount of 0.0001-20wt%, preferably 0.001-15wt%.

[0032] (H) Water, the remainder in each case to a total of 100% by weight of the composition.

[0033] All are based on the total weight of the composition, wherein the etching composition pH is preferably in the range of 1 to 7, most preferably in the range of 3 to 5. And wherein the wt% of the individual components in each case add up to 100 wt%. The present invention also provides a method for selectively etching silicon germanium in a silicon / silicon germanium stack using the above composition, the steps of which are as follows: The composition is contacted with a microelectronic device comprising a silicon / silicon germanium stack at a temperature of 20° C. to 70° C. to complete etching of the silicon germanium layer.

[0034] Furthermore, the contact time is less than 24 hours, preferably 1-60 minutes.

[0035] Furthermore, the contact temperature is preferably 20-70°C, more preferably 25-60°C.

[0036] Further, the SiGe / Si etching selectivity ratio is >50, preferably >100, more preferably >150, and most preferably >200.

[0037] Furthermore, the etching rate of Si is less than 10Å / min, preferably less than 5Å / min, and more preferably less than 1Å / min.

[0038] Furthermore, the rate of removing silicon germanium can be adjusted by increasing or decreasing etching conditions, such as component content and temperature.

[0039] Further, before etching, the entire device structure is cleaned with an aqueous solution containing 0.5 wt% HF at room temperature for about 30s-240s, preferably 60s, and more preferably 30s. After etching is completed, the etching solution can be easily removed from the microelectronic device by rinsing, washing or other removal steps. For example, the etching solution can be removed by rinsing with a rinsing solution such as deionized water or an organic solvent, and / or drying (such as spin drying, N2, steam drying, etc.).

[0040] The etching composition of the present invention is suitable for microelectronic devices including silicon and silicon germanium, preferably SiGe25, and in particular layers containing or consisting of SiGe alloys (such as high-K materials, low-K materials).

[0041] It should be understood that the term "silicon" as a material deposited on a microelectronic device includes, but is not limited to, amorphous silicon, crystalline silicon, polycrystalline silicon, p-type doped silicon, n-type doped silicon, and the like.

[0042] The "silicon germanium containing layer" or "SiGe layer" used in the present invention corresponds to a layer containing or consisting of a silicon germanium alloy known in the art and represented by the formula SixGey, where x+y=1.00. SiGe25 here means that y is 0.25.

[0043] As defined in the present invention, "high-K materials" (materials with high dielectric constants) are generally used to replace traditional silicon dioxide (SiO2) as the dielectric layer of capacitors. The high-K material can be hafnium dioxide (HfO2), hafnium oxynitride (HfON), zirconium dioxide (ZrO2), zirconium oxynitride (ZrON), aluminum oxide (Al2O3), aluminum oxynitride (AlON), hafnium silicon oxide (HfSiO2), hafnium aluminum oxide (HfAlO), zirconium silicon oxide (ZrSiO2), tantalum dioxide (Ta2O5), aluminum oxide, titanium oxide (TiO2), aluminum-doped hafnium dioxide, bismuth strontium titanium (BST) or platinum zirconium titanium (PZT).

[0044] As defined herein, "low-K dielectric materials" (materials with a dielectric constant <3.5) correspond to any material used as a dielectric material in a layered microelectronic device. Examples include silicon-containing organic polymers, silicon-containing hybrid organic / inorganic materials, organosilicate glass (OSG), TEOS, fluorinated silicate glass (FSG), silicon dioxide, and carbon-doped oxide (CDO) glass. It should be understood that low-K dielectric materials may have different densities and different porosities.

[0045] The beneficial effects of the present invention are as follows: 1. In the acidic etching solution, by adding fatty alcohol polyoxyethylene ether as a silicon inhibitor, the fatty alcohol polyoxyethylene ether forms a passivation film with the silicon surface through chemical reaction, which further improves the inhibitory effect on silicon, thereby ensuring the integrity and performance of the silicon nanolayer after etching. At the same time, the polyoxyethylene group has good hydrophilicity and dispersibility, which can disperse the particles generated during the etching process in the etching solution to prevent their agglomeration and deposition, which helps to obtain a smoother and flatter etching surface.

[0046] 2. Specific functional groups (such as hydroxyl, carboxyl, etc.) in SiGe stabilizer molecules can chemically adsorb with atoms or ions on the surface of SiGe materials. This adsorption can reduce the direct contact between active components (such as fluorides, oxidants, etc.) in the etching solution and the SiGe surface, thereby reducing the etching rate. It effectively enhances the stability and controllability of SiGe materials during the etching process and reduces abnormal reactions and losses of SiGe during the etching process. At the same time, these stabilizers can improve the fluidity of the etching solution, making it easier to penetrate into the tiny gaps of the structure. This helps to achieve a more uniform and in-depth etching effect and improve the accuracy and consistency of etching.

[0047] In summary, the present invention provides an efficient, reliable and controllable solution for the silicon germanium / silicon stack etching process in the manufacture of microelectronic devices through the dual guarantees of highly selective etching and SiGe etching stability, thereby effectively improving the yield and performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 SEM image of the etching structure of Si / SiGe25 laminated structure sheet using the formula of comparative example 1; Figure 2 SEM image of the etching structure of Si / SiGe25 stacked structure sheet using the recipe of Example 2; Figure 3 SEM image of the etching structure of Si / SiGe25 stacked structure wafer using the recipe of Example 5. DETAILED DESCRIPTION The embodiments of the present invention will be described in detail below with reference to examples. The following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention.

[0049] (1) Preparation: According to the components and contents in the table below, weigh the corresponding raw materials by percentage calculation to prepare different selective etching solutions, with water as the balance.

[0050] (2) Etching conditions: 30°C, 300 r / min stirring and soaking for 1-30 min.

[0051] (3) Etching test piece: Si (110), SiGe25 The formulations and test data of the embodiments and comparative examples are shown in Tables 1-5. Table 1 Etching solution formula ratio and test data of different silicon inhibitors

[0052] Table 2 Etching solution formula ratio and test data of different silicon germanium etching stabilizers

[0053] Table 3 Etching rate and selectivity of SiGe with different contents

[0054] Depend on Figure 1 (Comparative Example 1 Formulation) and Figure 2 (Formula of Example 2) shows that in an acidic etching solution, the aSi etching rate can be reduced by adding fatty alcohol polyoxyethylene ether, which leads to a higher SiGe / aSi selectivity. At the same time, the polyoxyethylene group has good hydrophilicity and dispersibility, and can disperse the particles generated during the etching process in the etching solution to prevent them from agglomerating and depositing, which helps to obtain a smoother and flatter etching surface. Figure 3 (Formula of Example 5) It can be seen that adding SiGe stabilizer with specific functional groups helps to achieve a more uniform and in-depth etching effect and improve the accuracy and consistency of etching.

[0055] The above experimental data show that the etching selectivity and etching uniformity can be improved by adding compounds such as silicon inhibitors and SiGe etching stabilizers. It can be seen from Examples 5, 6 and 7 that the SiGe25 / Si etching selectivity ratio is as high as 230 when the silicon inhibitor and SiGe etching stabilizer are used together.

[0056] The foregoing description is primarily for illustrative purposes. Although the present invention has been shown and described with respect to exemplary embodiments thereof, it will be appreciated by those skilled in the art that the foregoing and various other changes, omissions and additions may be made in its form and details without departing from the spirit and scope of the present invention.

Claims

1. A composition suitable for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device, characterized in that The composition comprises the following components by mass fraction: Polyalkylene imine 0.0001-10 wt%; Fluoride 0.001-10 wt%; Oxidant 0.1-70 wt%; Buffer composition 0.01-50wt%; Silicon inhibitor 0.00001-1wt%; Silicon germanium etching stabilizer 0.0001-1wt%; Defoaming agent 0.0001-20wt%; The balance is water; Preferably, the composition comprises the following components by mass fraction: Polyalkylene imine 0.0005-5 wt%; Fluoride 0.002-5 wt%; Oxidant 1-60 wt%; Buffer composition 0.05-30 wt%; Silicon inhibitor 0.0001-0.5 wt%; Silicon germanium etching stabilizer 0.001-0.01 wt%; Defoaming agent 0.001-15wt%; The balance is water.

2. The composition for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to claim 1, characterized in that: The polyalkylene imine is polyethylene imine; The preferred PEI molecular weight is 600-7w, more preferably 800-6w, and most preferably 2k-2w.

3. The composition for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to claim 1, characterized in that: The fluoride is selected from at least one of hydrofluoric acid, ammonium fluoride, ammonium bifluoride, fluoroboric acid, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride and fluorosilicate; and the oxidant is hydrogen peroxide.

4. The composition for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to claim 1, characterized in that: The buffer composition is an optional amine-containing compound and a polyfunctional organic acid.

5. The composition for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to claim 4, characterized in that: The buffer composition is an acetic acid-ammonium acetate buffer system or a citric acid-ammonium citrate buffer system.

6. The composition for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to claim 5, characterized in that: The pH value of the composition is 1-7, preferably 3-5.

7. A composition suitable for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to any one of claims 1 to 6, characterized in that: The silicon inhibitor is selected from fatty alcohol polyoxyethylene ethers having the following formula: RO(CH2CH2O)nH, Wherein R represents a hydrocarbon group, which can be a saturated or unsaturated C12~C18 hydrocarbon group; the hydrocarbon group is a straight-chain hydrocarbon group or a branched hydrocarbon group; n is the number of ethylene oxide additions.

8. A composition suitable for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to any one of claims 1 to 7, characterized in that: The silicon germanium etching stabilizer is polyacrylic acid, polyethylene glycol, polyvinyl pyrrolidone and a combination thereof; The defoaming agent is selected from non-silicon defoaming agents such as fatty alcohols, fatty acids, fatty acid esters, and amides.

9. Use of the composition for selectively removing silicon germanium relative to silicon from a silicon germanium / silicon stack in a microelectronic device according to claims 1 to 8, characterized in that: The composition is used in a process containing a Si / SiGe heterostructure. The composition is used in a method for increasing the etching rate of silicon germanium relative to silicon in a composite semiconductor device containing silicon and silicon germanium. The method comprises the following steps: A composite semiconductor device comprising a silicon germanium / silicon stack is contacted with a composition according to any one of claims 1 to 8; and the semiconductor device is rinsed after the silicon germanium is at least partially removed, wherein the etching selectivity of silicon germanium relative to silicon is >50, preferably >100, more preferably >150, and most preferably >200.

10. The use according to claim 11, characterized in that The method further comprises the step of drying the microelectronic device; The contacting step is performed at a temperature of 25°C to 70°C.

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