Silicon etching with dopant-type selectivity

Abstract

The present invention provides an etching solution composition for silicon that yields an etching rate corresponding to the silicon dopant type, and a method for etching a surface having a first silicon region that is n-type and a second silicon region that differs from the first silicon region in terms of dopant type. [Solution] The etching solution composition provides an etching rate for silicon that corresponds to the silicon dopant type. The etching solution composition contains a base and an additive other than the base. The additive has 1 to 6 carbon atoms per molecule.

Description

[Technical Field]

[0001] Cross-references to related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 705,875, filed on 10 October 2024, which is incorporated herein by reference in its entirety.

[0002] This disclosure relates generally to the technical field of semiconductor device manufacturing, and more particularly to wet etching processes for semiconductors. [Background technology]

[0003] Semiconductor photolithography is a mature and sophisticated technique used to fabricate highly advanced, small-scale integrated electronic devices. The fundamental process in most photolithography operations is mask etching of semiconductor or dielectric structures. In mask etching, a photoresist is applied as a blanket layer to cover a semiconductor wafer or die portion of a wafer and cured by ultraviolet (UV) light projected through a carefully aligned optical mask. Through photopolymerization and / or photocrosslinking, selected areas of the photoresist layer solidify in a pattern defined by the optical mask upon curing, or degrade by UV light. A solvent is then used to remove uncured or degraded portions of the photoresist, leaving a pattern consisting of protected and unprotected regions.

[0004] Subsequent processing may vary depending on the embodiment. In plasma etching, an unprotected area of ​​the semiconductor wafer or die is exposed to high-energy reactants formed in the plasma. Such reactants convert the unprotected solid material into a gaseous residue. In wet (i.e., liquid-phase) etching, the unprotected area is exposed to a corrosive solution that dissolves unwanted materials, after which the soluble residue is washed away. In both embodiments, subsequent processing typically requires the removal of the entire hardened photoresist from the surface of the wafer or die. For this purpose, a well-formulated solvent composition can be used in the wet etching process.

[0005] For example, Patent Document 1 discloses an etching solution suitable for selective removal of polysilicon from silicon dioxide from microelectronic devices, comprising water; about 1% by mass of tetramethylammonium hydroxide (TMAH); about 15% to about 20% by mass of monoethanolamine (MEA); about 50% to about 59.5% by mass of ethylene glycol (EG); about 0.5% by mass of 8-hydroxyquinoline (8-HQ); and optionally a surfactant. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] United States Patent Publication No. 11,180,697 [Overview of the Initiative]

[0007] One aspect of this disclosure relates to an etching solution composition for silicon that provides an etching rate corresponding to the silicon dopant type. The etching solution composition comprises a base and an additive other than the base. The additive has 1 to 6 carbon atoms per molecule.

[0008] Another aspect of the present disclosure relates to a method for etching a surface having a first silicon region which is n-type and a second silicon region which differs from the first silicon region with respect to the dopant type. The method comprises exposing the surface to an etching solution composition which provides an etching rate with respect to silicon that corresponds to the dopant type. The etching solution composition comprises a base and an additive separate from the base, the additive having 1 to 6 carbon atoms per molecule.

[0009] This summary is provided to introduce, in a simplified form, a selection of concepts that will be further described in embodiments for carrying out the invention. This summary is not intended to identify any important or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The claimed subject matter is not limited to embodiments that resolve any or all of the defects described in any part of this disclosure. [Brief explanation of the drawing]

[0010] [Figure 1] This shows an exemplary lateral resection of an epitaxial p-type silicon (p-Si) layer. [Figure 2] This shows a method for the complete removal of the epitaxial p-type Si layer. [Figure 3] Table 1 of this disclosure shows the molecular structures of the compounds. [Figure 4] This describes an exemplary method for etching a surface having a first silicon region that is n-type and a second silicon region that differs from the first silicon region in terms of dopant type or dopant density. [Modes for carrying out the invention]

[0011] Wet etching can offer certain advantages over plasma etching for several applications in semiconductor manufacturing. For example, wet etching tools and chemicals are typically less expensive than those for plasma etching, resulting in lower operating costs. In contrast to plasma etching, wet etching is performed at lower temperatures, simplifying the processing of heat-sensitive materials and structures. Wet etching can also result in cleaner surfaces with less residue compared to plasma etching, which may require additional cleaning protocols due to residues and by-products from the etching gas. Furthermore, wet etching is inherently more isotropic, which can be advantageous in applications where isotropic etching is the most efficient process route to a particular form and / or device configuration, or in applications for undercutting sacrificial layers.

[0012] Finally, wet etching can provide a greater relative etching rate (i.e., higher selectivity) for one material compared to another when multiple different materials are subjected to the same etching conditions simultaneously. Available etching solutions (etching compositions) can, for example, etch silicon and silicon oxide at rates that differ by several orders of magnitude. This feature provides functional selectivity for semiconductor etching versus dielectric etching. Other etching solutions can easily distinguish between dissimilar semiconductors (e.g., germanium (Ge) versus silicon (Si)). Yet another etching solution is available that gives a 17-fold difference in etching rate between 100 faces of silicon and 111 faces. Such selectivity can be utilized to reduce the number of mask alignment and curing steps required in a given manufacturing process, and / or to enable the selective removal of unprotected structures such as undercuts.

[0013] Here, the inventors of the present invention have sought to extend the selectivity of the wet etching process to semiconductor systems where the material differences between separate unprotected regions of a wafer or die are minimal. This includes semiconductor materials that expose the same crystal plane and differ only in dopant type.

[0014] Doping involves introducing impurities into a semiconductor. These impurities can generate space charges within the doped semiconductor, which alters the Fermi levels of electrons within the semiconductor relative to the valence band and conduction band.

[0015] The n-type doping process involves adding elements with more than four valence electrons to a silicon lattice. Common n-type dopants include phosphorus (P) and arsenic (As), both of which have five valence electrons per atom. In effect, each n-type dopant atom adds one electron to the conduction band of silicon.

[0016] The typical dopant density of n-type Si at low to moderate dopant levels is per cubic centimeter (cm³). 3 ) 10 per person 15 ~10 17 It consists of 1 atom. In many semiconductor applications such as integrated circuits and transistors, n-type silicon is doped in this range. The typical dopant density of n-type Si at high dopant levels is 1 cm³. 3 10 hits 18 ~10 20 These are individual atoms. Doping concentrations in this range can be used in applications requiring high electronic conductivity, such as certain types of power devices or certain high-speed transistors.

[0017] The p-type doping process involves adding elements with fewer than four valence electrons to a silicon lattice. Common p-type dopants include boron (B), gallium (Ga), and indium (In), all of which have three valence electrons per atom. In effect, each p-type dopant atom adds one hole to the silicon valence band.

[0018] The typical dopant density of p-type Si at low to medium dopant levels is 10 3 to 10 15 to 10 17 atoms per cm. In many semiconductor applications such as integrated circuits and transistors, p-type silicon is doped within this range. The typical dopant density of p-type Si at high dopant levels is 10 3 to 10 18 to 10 20 atoms per cm. In applications that require high hole conductivity, such as certain types of power devices or certain high-speed transistors, doping concentrations within this range can be used.

[0019] Dopants can be added to silicon by diffusion or ion implantation. In diffusion, the wafer is exposed to a gas containing dopant atoms at a high temperature (typically between 800 and 1200 °C). The dopant diffuses into the silicon wafer, gradually penetrating the surface and being incorporated into the silicon lattice. In ion implantation, dopant ions are accelerated in an electric field and directed towards the silicon wafer. The ions penetrate the surface and are embedded in the silicon lattice. This method allows for more precise control of the doping concentration and depth compared to diffusion. After the doping process, the wafer is typically subjected to a thermal annealing step. Thermal annealing includes a heating process that helps repair the damage caused by ion implantation and activates the dopants by allowing them to occupy their expected positions within the silicon lattice.

[0020] Certain portions of the semiconductor device can include intrinsic silicon (i-Si) where the concentration of conduction band electrons is equal to the concentration of valence band holes. In some examples, this type of silicon is extremely pure and may not be subject to any n-type or p-type doping processes (i.e., undoped or “not doped”). In other examples, the i-Si may be “intrinsically doped,” i.e., the n-type dopants and p-type dopants are present at approximately equal (and typically low) concentrations such that the Fermi level of electrons in the silicon is approximately the same as that of undoped silicon. As used herein, the term “dopant type” includes p-type, n-type, i-type, and undoped silicon.

[0021] Amorphous silicon (a-Si) is a non-crystalline form of silicon that is different from the crystalline silicon used in most semiconductor applications. Amorphous silicon lacks a long-range periodic atomic arrangement and exhibits somewhat different electrical properties compared to crystalline silicon. For example, amorphous silicon has a larger bandgap than crystalline silicon. Amorphous silicon is typically deposited as a thin film using techniques such as CVD or PE-CVD. Amorphous silicon is often deposited in thin layers and is thus suitable for use in flexible substrates and various electronic devices. Generally speaking, it is possible to dope a-Si. However, in the studies reported in this disclosure, the a-Si was intrinsic (i-Si). [

[0022] [ [ One of ordinary skill in the art will appreciate that the dopant density in silicon for the manufacture of integrated circuits rarely exceeds 0.01 wt%. Thus, for example, selective etching of p-type silicon (p-Si) in the presence of n-type silicon (n-Si) is more difficult compared to selective etching of all atoms being chemically different materials. Referring now to the drawings, FIGS. 1 and 2 illustrate exemplary uses of the etching liquid compositions and methods disclosed herein. [

[0023] [ [Figure 1 shows an exemplary lateral resection of an epitaxial p-Si layer 102 formed on a SiGe layer 104. An epitaxial n-Si layer 106 is formed on top of the epitaxial p-Si layer. Etching is achieved by a wet etching process in which the surfaces of the p-Si and n-Si are simultaneously exposed to the etching solution composition. As shown in the figure, the n-Si withstands etching with only very slight dimensional changes, while the width of the p-Si layer is significantly reduced.

[0024] Figure 2 shows an embodiment of the complete removal of the epitaxial p-Si layer 202, which is formed covering the epitaxial n-Si layer 206 formed on the SiGe layer 204. Since the etching solution composition etches the p-Si much faster than it etches the n-Si, layer 206 is preserved in this process.

[0025] As described above, wet etching uses a specific etching solution composition to remove material from unprotected areas of a wafer or die. The etching solution composition is selected based on the etching rate of the material in question relative to one or more coexisting materials that may also be present on the surface being etched. In this disclosure, the material in question is a semiconductor of a specific dopant type or dopant level. Exemplary coexisting materials may be the same semiconductor with different dopant types, or the same dopant type but with higher or lower dopant densities. Other coexisting materials include the same semiconductor exhibiting different crystal planes (e.g., (100) vs. (111)), different semiconductors (e.g., Ge vs. Si), dielectrics such as silicon oxide (SiO2) and silicon nitride (Si3N4), cured photoresists (including one or more crosslinked polymers), and various additional structures formed on the semiconductor wafer or die surface (e.g., metallic or epitaxial semiconductor structures). Such structures may include, among others, aluminum, copper, tungsten, molybdenum, cobalt, tantalum, and gold.

[0026] [Table 1]

[0027] Table 1 shows embodiments of etching solution compositions 1 to 9 of the series of examples, along with comparative etching solution compositions C1 to C4. Each of the etching solution compositions of the examples and comparative examples is an aqueous solution. The amount of water in each etching solution composition may exceed 90% by mass.

[0028] Each of the etching solution compositions in Table 1 contains a specific compound as a solute in an aqueous solution. Figure 3 shows the molecular structures of the compounds used in the etching solution compositions of the examples and comparative examples. TMAH represents tetramethylammonium hydroxide. DEHA represents N,N-diethylhydroxylamine. DMHD represents 2,5-dimethyl-2,5-hexanediol. TETA represents triethylenetetraamine. TAEA represents tris(2-aminoethyl)amine, and DETA represents diethylenetriamine.

[0029] Each of the etching solution compositions in Table 1 contains a base (i.e., an alkaline component). Since the same base, i.e., 1% by mass of TMAH, was used in all the etching solution compositions of the examples and comparative examples herein, the base is not indicated in the table column. The amount of base is not particularly limited, and base concentrations ranging from 0.01% by mass to about 20% by mass are assumed. More preferably, the amount of base may be less than 10% by mass in some examples to avoid excessive corrosiveness. Furthermore, as an example of this disclosure, the lower limit of the amount of base may be 0.1% by mass or more, or 0.5% by mass or more. The upper limit of the amount of base may be 15% by mass or less, or 10% by mass or less. Bases other than TMAH may be used. Generally speaking, the base must be readily soluble in water. Alternative bases include other quaternary ammonium bases, such as tetraalkylammonium hydroxides, including tetraethylammonium hydroxide (TEAH). Sodium hydroxide and potassium hydroxide can also be used, but these bases should be used with caution as they may introduce mobile cations into silicon under wet etching conditions.

[0030] Each of the etching solution compositions in the examples of Table 1, as a preferred example of the present art, contains one or more additives separate from the bases introduced above. In some examples, at least one additive may contain an amine. The term "amine" should be interpreted broadly. The amine may be primary, secondary, or tertiary. The group of atoms bonded to the nitrogen atom in the amine may be saturated, unsaturated, aliphatic, or aromatic, provided that it is stable at the pH of the etching solution composition. In this disclosure, "amine" is a genus that includes monoamines, diamines, triamines, and polyamines. The amine may be monofunctional, difunctional, or polyfunctional. Examples of functional groups compatible with the amine group and consistent with this disclosure include hydroxyl groups, ether groups, and amide groups. Thus, the term "amine" may be used, for example, to refer to a molecule having at least one amine group and one or more alcohol groups. Alternatively, one alcohol group may be directly bonded to the amine-nitrogen atom of the amine, and the resulting hydroxylamine can still be called an "amine." Similar to the bases in the etching solution compositions of the examples herein, the amines must be readily soluble in water at the pH of the etching solution composition.

[0031] Each of the etching solution compositions 1 to 9 in the examples yields an etching rate for silicon corresponding to the silicon dopant type. The sensitivity to the dopant type is evident in the fourth, fifth, and sixth columns of Table 1. Column 4 shows the etching rate for n-Si (in nanometers per minute (nm / min)), and column 5 shows the corresponding etching rate for amorphous silicon (a-Si) films. Column 6 shows the ratio of these rates.

[0032] The etching rates shown in Table 1 were determined as follows: An n-type Si epitaxial film was grown on a silicon germanium (SiGe) wafer by chemical vapor deposition (CVD). An a-Si film was grown on a SiO2-coated substrate by CVD. The wafers coated with each film were divided into several test samples of approximately 1 to 10 square centimeters. The film thickness of each test sample was measured by ellipsometry or XRF.

[0033] For each test sample, 100 ml (mL) of aqueous hydrofluoric acid (HF, 0.5 mass%) was poured into the first plastic cup and magnetically stirred at 300 rpm at 25°C. The same volume of etching solution composition was poured into the second plastic cup and magnetically stirred at 300 rpm at 55°C. 100 mL of deionized water was poured into the third and fourth plastic cups and magnetically stirred at 300 rpm at 25°C. Each test sample was placed in the first cup for 60 seconds, then transferred to the third cup for 5 seconds, then to the second cup for 60 seconds, and finally to the fourth cup for 5 seconds. The samples were then dried, and the film thickness was measured repeatedly using an ellipsometer or XRF.

[0034] Under conventional wet etching chemical reactions, n-type Si is etched somewhat more rapidly than other dopant-type silicon. This is confirmed in the comparative examples in Table 1. However, etching compositions 1-9 of the examples produce the opposite effect, namely, a lower etching rate for n-type Si than for a-Si, which is considered to be intrinsically doped silicon (i-Si). Therefore, using the etching compositions of the examples herein, the etching rate is lower for n-type silicon than for intrinsically doped silicon, or lower for n-type silicon than for other dopant-type silicon.

[0035] In the etching solution compositions 1 to 9 of the examples in Table 1, each additive has 1 to 6 carbon atoms per molecule. While this disclosure does not tie to any particular theory, it is thought that at least one additive in the etching solution compositions of the examples improves the etching rates of p-Si and a-Si, while having little effect on the etching rate of n-type Si. Additives having 7 or more carbon atoms per molecule, even if readily soluble in water, may strongly adsorb to the hydrophobic surface of silicon, potentially negating the rate-improving effect. For example, DETA, triethanolamine, and TETA appear to be associated with good selectivity in some compositions.

[0036] Some of the etching solution compositions in Table 1 contain two or more additives separate from the base and distinct from each other. In examples containing multiple additives, at least two of the additives may have 1 to 6 carbon atoms per molecule for the reasons mentioned above. In some examples, at least one of the additives may be a corrosion inhibitor such as an N,N-disubstituted hydroxylamine, and in etching solution compositions 1, 2, 4, 5, and 6, the additive is DEHA. In etching solution composition 3 of the examples, 1-butanol is the additive. Other branched and unbranched alcohols and polyols may also be used as additives. Some etching solution compositions may contain other corrosion inhibitors in addition to the specified additives, but their characteristics are not essential.

[0037] Figure 4 shows an exemplary embodiment of method 400 for etching a surface having a first silicon region that is n-type and a second silicon region that differs from the first silicon region in terms of dopant type or dopant density.

[0038] In method 400, step 401A, a photoresist is applied to the surface. In step 401B, a mask is positioned on the surface. In step 401C, the photoresist is cured by UV exposure through the mask, such that the cured photoresist does not extend over the first or second silicon region. In step 401D, the uncured photoresist is removed from the surface.

[0039] In 401E, the surface is exposed to an etching solution composition that yields an etching rate for silicon corresponding to the dopant type. The etching solution composition comprises a base and an additive separate from the base. As shown by the etching solution compositions of the examples herein, the additive may have 1 to 6 carbon atoms per molecule. In some examples, the etching rate of the composition is lower for a first n-type silicon than for silicon of another dopant type, such as a second region. Examples of other dopant types include one or more of p-type, intrinsically doped, amorphous, and / or undoped.

[0040] In some examples, the base includes a quaternary ammonium base such as TMAH or TEAH. In some examples, the additive includes an amine. In some examples, the etching solution composition may include two or more additives that are distinct from the base and distinct from each other. In some examples, at least two additives may have 1 to 6 carbon atoms per molecule. In some examples, the amine or other additive may include an N,N-disubstituted hydroxylamine such as DEHA.

[0041] In 401F, the surface is rinsed. In some examples, the rinsing solution may contain water. In some examples, the rinsing solution may contain an alcohol such as isopropyl alcohol. Optionally, after rinsing and properly drying the surface, one or more dry etching processes may be performed as needed.

[0042] No aspect of this disclosure should be construed as restrictive, as numerous modifications, extensions, and omissions are equally likely. For example, while the method in Figure 4 demonstrates selective etching after circuit patterning, selective etching by the methods herein may also be useful before patterning or between separate patterning procedures. The foregoing description specifically refers to etching compositions having selectivity based on dopant type, but the same or similar etching compositions may exhibit selectivity of etching rate based on dopant density, such as normal dopant density versus high dopant density versus degenerate doping. Furthermore, the same or similar etching compositions may exhibit sensitivity of etching rate based on dopant depth, such as deep doping versus shallow doping.

[0043] Again, while the aspects of this disclosure are not intended to be tied to any particular theory, the main chemical effect of dopant type and dopant density may be that it affects the space charge generated within the semiconductor material when the semiconductor surface reaches electrostatic equilibrium with the etching solution composition. Such equilibrium causes charge to accumulate at the interface between the semiconductor surface and the solution, depending on the dopant type, dopant density, and dopant depth. The relative etching rate reported in this disclosure as a function of dopant type is likely to be attributable to the changes in surface chemistry resulting from the accumulated surface charge and is therefore likely to be extendable to dopant depth and dopant density.

[0044] This disclosure is presented with reference, by example, to the accompanying drawings. Components, process stages, and other elements that may be substantially identical in one or more of the drawings are synchronously identified and described with minimal repetition. However, it should be noted that synchronously identified elements may differ to some extent. Furthermore, it should be noted that the drawings are schematic and not generally drawn to scale. Rather, the various drawing scales, aspect ratios, and number of components shown in the drawings may be intentionally distorted to make certain features or relationships easier to understand.

[0045] The configurations and / or methods described herein are illustrative in nature and numerous variations are possible; therefore, it will be understood that these particular embodiments or examples should not be considered limiting. The specific routines or methods described herein may represent one or more of any number of processing strategies. Thus, the various operations illustrated and / or described may be performed in the order illustrated and / or described, in other orders, in parallel, or omitted. Similarly, the order of the processes described above may be changed. In some examples, the terms “about” and “approximately” extend x to include any value within the range of 0.9x to 1.1x when applied to a numerical value x; and in some examples, these terms extend x to include any value within the range of 0.95x to 1.05x.

[0046] Furthermore, unless otherwise specified, each configuration and parameter disclosed herein may be in any combination. Furthermore, unless otherwise specified, the upper and lower limits of the values ​​disclosed herein may be in any combination. In addition, in this specification, "comprise" may be replaced with "consist essentially of" and "consist of" as needed. Also, unless otherwise specified, in this specification, parts by mass or mass percent are used. In this specification, the amount used may be the content, and the content may be the amount used.

[0047] The subject matter of this disclosure includes all novel, non-obvious, and partial combinations of the various processes, systems, and configurations disclosed herein, as well as other features, functions, operations, and / or characteristics, and all of their equivalents.

[0048] This disclosure also discloses embodiments as illustrated below. <1> An etching solution composition that provides an etching rate corresponding to the dopant type of silicon, Bases and An additive other than the aforementioned base and Includes, The additive is an etching solution composition having 1 to 6 carbon atoms per molecule. <2> The etching rate is lower for n-type silicon than for intrinsically doped silicon, or lower for n-type silicon than for silicon of another dopant type. <1> The etching solution composition described above. <3> The aforementioned base includes a quaternary ammonium base. <1> The etching solution composition described above. <4> The aforementioned additive contains an amine. <1> The etching solution composition described above. <5> The additive is a first additive, and the etching solution composition further comprises a second additive, which is different from the base and different from the first additive. <1> The etching solution composition described above. <6> The second additive has 1 to 6 carbon atoms per molecule. <5> The etching solution composition described above. <7> The second additive comprises an amine or an alcohol. <5> The etching solution composition described above. <8> A method for etching a surface having a first silicon region which is n-type and a second silicon region which differs from the first silicon region with respect to the dopant type, The etching solution composition provides an etching rate for silicon according to the dopant type, and comprises a base and an additive other than the base, wherein the additive is exposed to the etching solution composition having 1 to 6 carbon atoms per molecule. A method that includes this. <9> The etching rate for the n-type silicon is lower than that of other dopant-type silicon. <8> Methods used. <10> The process involves applying a photoresist to the aforementioned surface, Aligning the mask on the aforementioned surface, The curing of the photoresist via the mask is performed such that the cured photoresist does not extend over the first silicon region or the second silicon region. To remove the uncured photoresist and Further including, <8> Methods used. <11> The process further includes rinsing the surface and / or performing a dry etching process. <8> Methods used. <12> The aforementioned base includes a quaternary ammonium base. <8> Methods used. <13> The aforementioned additive contains an amine. <8> Methods used. <14> The additive is a first additive, and the etching solution composition further comprises a second additive, which is different from the base and different from the first additive. <8> Methods used. <15> The second additive has 1 to 6 carbon atoms per molecule. <14> Methods used. <16> The first additive comprises an amine or an alcohol. <14> Methods used. <17> An etching solution composition that provides an etching rate corresponding to the dopant type of silicon, Bases and A first additive, distinct from the aforementioned base, having 1 to 6 carbon atoms per molecule, A second additive, distinct from the aforementioned base and the first additive, having 1 to 6 carbon atoms per molecule, An etching solution composition containing the following: <18> The aforementioned base includes a quaternary ammonium base. <17> The etching solution composition described above. <19> The first additive contains an amine, <17> The etching solution composition described above. <20> The first additive comprises an amine or an alcohol, and the second additive comprises an amine or an alcohol. <17> The etching solution composition described above. [Explanation of Symbols]

[0049] 102 Epitaxial p-Si layer 10⁴ SiGe layer 106 Epitaxial n-Si layer 202 Epitaxial p-Si layer 204 SiGe layer 206 Epitaxial n-Si layer 400(401A~401F) Method

Claims

1. An etching solution composition that provides an etching rate corresponding to the dopant type of silicon, Bases and An additive other than the aforementioned base and Includes, The additive is an etching solution composition having 1 to 6 carbon atoms per molecule.

2. The etching solution composition according to claim 1, wherein the etching rate is lower for n-type silicon than that of intrinsically doped silicon, or lower for n-type silicon than that of silicon of another dopant type.

3. The etching solution composition according to claim 1, wherein the base comprises a quaternary ammonium base.

4. The etching solution composition according to claim 1, wherein the additive comprises an amine.

5. The etching solution composition according to claim 1, wherein the additive is a first additive, and the etching solution composition further comprises a second additive which is different from the base and different from the first additive.

6. The etching solution composition according to claim 5, wherein the second additive has 1 to 6 carbon atoms per molecule.

7. The etching solution composition according to claim 5, wherein the second additive comprises an amine or an alcohol.

8. A method for etching a surface having a first silicon region which is n-type and a second silicon region which differs from the first silicon region with respect to the dopant type, The etching solution composition provides an etching rate for silicon according to the dopant type, and comprises a base and an additive other than the base, wherein the additive is exposed to the etching solution composition having 1 to 6 carbon atoms per molecule. A method that includes this.

9. The method according to claim 8, wherein the etching rate is lower for the n-type silicon than for another dopant-type silicon.

10. The process involves applying a photoresist to the aforementioned surface, Aligning the mask on the aforementioned surface, The curing of the photoresist via the mask is performed such that the cured photoresist does not extend over the first silicon region or the second silicon region. To remove the uncured photoresist and The method according to claim 8, further comprising:

11. The method according to claim 8, further comprising rinsing the surface and / or performing a dry etching process.

12. The method according to claim 8, wherein the base includes a quaternary ammonium base.

13. The method according to claim 8, wherein the additive comprises an amine.

14. The method according to claim 8, wherein the additive is a first additive, and the etching solution composition further comprises a second additive which is different from the base and different from the first additive.

15. The method according to claim 14, wherein the second additive has 1 to 6 carbon atoms per molecule.

16. The method according to claim 14, wherein the first additive comprises an amine or an alcohol.

17. An etching solution composition that provides an etching rate corresponding to the dopant type of silicon, Bases and A first additive, distinct from the aforementioned base, having 1 to 6 carbon atoms per molecule, A second additive, which is separate from the base and separate from the first additive, and has 1 to 6 carbon atoms per molecule, An etching solution composition containing the following:

18. The etching solution composition according to claim 17, wherein the base comprises a quaternary ammonium base.

19. The etching solution composition according to claim 17, wherein the first additive comprises an amine.

20. The etching solution composition according to claim 17, wherein the first additive comprises an amine or an alcohol, and the second additive comprises an amine or an alcohol.

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