TW201306120A - Etching method, etching liquid used in the same and method of manufacturing semiconductor substrate product using the same - Google Patents

Abstract

An etching method, an etching liquid used in the same and a method of manufacturing a semiconductor substrate product using the same are provided, the etching method is a selective wet etching which first dissolves a layer including Ti, and effectively cleans and removes a residue produced by etching, ashing, and etc. The etching method is a method which applies a specific etching liquid to a semiconductor substrate containing a first layer including Ti and a second layer including at least one from Cu, SiO, SiN, SiOC and SiON, and then selectively etch the first layer. The specific etching liquid contains a basic compound including an organic amine compound and an oxidizing agent in an aqueous medium, wherein the pH of the specific etching liquid is from 7 to 14.

Description

Etching method, etching liquid therefor, and method of manufacturing semiconductor substrate product using the same

The present invention relates to a method of selectively etching a specific metal material, an etching solution therefor, and a method of manufacturing a semiconductor substrate product using the same.

The miniaturization and diversification of semiconductor components are increasing, and the processing methods thereof involve many aspects in each component structure or manufacturing step. In the etching of the substrate, various chemical species and processing conditions are proposed in accordance with the type and structure of the material of the substrate in both the dry etching and the wet etching, and further research and development are performed as much as possible.

Among them, a technique of precisely etching to form an element structure such as a complementary metal oxide semiconductor (CMOS) or a dynamic random access memory (DRAM) is important, and wet etching using a chemical liquid is exemplified as one of the techniques. For example, precision etching is required in the fabrication of circuit wiring or a substrate including a metal electrode material in a micro transistor circuit. Or the same in the fabrication of the electrode structure in the capacitor structure of the above DRAM. However, the conditions or chemical liquids for selectively etching the respective layers applied to the substrate including the metal electrode or the like have not been sufficiently studied.

There is an example in which a chemical liquid for etching a tantalum oxide constituting a device substrate is studied. For example, Patent Document 1 proposes a method of efficiently etching a thermal oxide film of a tantalum wafer using hydrofluoric acid and ammonium fluoride.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-177998

The inventors of the present invention have explored a chemical liquid which can selectively etch a layer containing Ti and an etching method using the same. Moreover, the following etching methods and development of chemical liquids for the same are the technical problems: in the wet etching step, the etching method can simultaneously clean and remove the plasma due to the semiconductor manufacturing process. The residue generated by etching or ashing can greatly improve the manufacturing efficiency.

That is, an object of the present invention is to provide an etching method capable of preferentially dissolving a layer containing Ti, and an etching method capable of effectively cleaning and removing residues due to etching, ashing, etc., and etching therefor. Liquid, a method of producing a semiconductor substrate product using the same.

The above problems can be solved by the following methods.

(1) An etching method for applying a specific etching liquid to a semiconductor substrate including a first layer containing Ti and a second layer containing at least one of Cu, SiO, SiN, SiOC, and SiON, and the first etching solution The layer is subjected to selective etching, characterized in that the specific etching liquid contains a basic compound containing an organic amine compound and an oxidizing agent in an aqueous medium, and has a pH of 7 to 14.

(2) The etching method according to (1), wherein the basic compound is a compound represented by the following formula (I): N(R) ₄ . OH.........Formula (I)

(R represents a substituent; a plurality of R may be different from each other).

(3) The etching method according to (1) or (2), wherein the basic compound is tetramethylammonium hydroxide, tetraethylammonium hydroxide, or tetrapropylammonium hydroxide.

(4) The etching method according to (1), wherein the oxidizing agent is hydrogen peroxide, ammonium persulfate, perboric acid, peracetic acid, periodic acid, perchloric acid or a combination thereof.

(5) The etching method according to (1), wherein a ratio (R1/R2) of the etching rate (R1) of the first layer to an etching rate (R2) of the second layer is 30 or more.

(6) The etching method according to the above aspect, wherein the semiconductor substrate includes a third layer containing W, and the third layer is exposed, and the first layer is applied by using an etching solution containing nitric acid. The selective etching is performed by selectively etching the first layer by applying the specific etching liquid in a state where the copper of the second layer is exposed.

(7) The etching method according to (1), wherein the etching is performed in a range of from 20 ° C to 80 ° C.

(8) An etching solution for selectively etching a first layer containing Ti with respect to a second layer containing at least one of Cu, SiO, SiOC, and SiON, in an aqueous medium It contains a basic compound containing an organic amine compound and an oxidizing agent, and has a pH of 7 to 14.

(9) The etching solution according to (8), wherein a ratio (R1/R2) of the etching rate (R1) of the first layer to an etching rate (R2) of the second layer is 30 or more.

(10) The etching solution according to (8), wherein the concentration of the basic compound is 0.05% by mass to 50% by mass.

(11) The etching solution according to (8), wherein the concentration of the oxidizing agent is from 0.5% by mass to 20% by mass.

(12) The etching solution according to (8), which further comprises a water-soluble organic solvent.

(13) The etching solution according to (12), wherein the water-soluble organic solvent is a diol compound.

(14) A kit of etching liquids, wherein the etching liquid according to (8) is combined with an etching liquid containing nitric acid, and the semiconductor substrate comprises a third layer containing W, the first The first layer is selectively etched by applying the etchant containing nitric acid in a state where the three layers are exposed, and the first etchant is applied to the first layer in a state where the copper of the second layer is exposed. The layer is selectively etched.

(15) A method of producing a semiconductor substrate product, comprising the steps of: preparing a semiconductor substrate comprising a first layer containing Ti, and at least one of Cu, SiO, SiN, SiOC, and SiON; a second layer; and a step of selectively etching the first layer by applying a specific etching liquid to the semiconductor substrate; The specific etching solution is used for an etching solution containing a basic compound containing an organic amine compound and an oxidizing agent in an aqueous medium and having a pH of 7 to 14.

(16) The method for producing a semiconductor substrate according to the above aspect, wherein the semiconductor substrate further includes a semiconductor substrate further including a third layer including W, and the nitrile is contained in a state in which the third layer is exposed. The first layer is selectively etched by the etching liquid, and the first layer is selectively etched by applying the specific etching liquid while the copper of the second layer is exposed.

According to the etching method and the etching solution of the present invention, selective wet etching in which the layer containing Ti is preferentially dissolved can be performed, and the residue generated by etching, ashing, or the like can be effectively removed and removed.

According to the method for producing a semiconductor substrate of the present invention, a semiconductor substrate product having a specific structure according to the above-described manufacturing method can be produced by using the above-described excellent etching selectivity. Further, since the residue is excellent in removability, the removal step can be omitted, and the production of an extremely efficient semiconductor substrate can be performed.

Further, the following steps may be combined to perform processing of a semiconductor substrate having Cu and W on a circuit wiring, and efficient production of the device: a processing step using the etching liquid having protective properties against Cu, and using The layer of W has a protective treatment step of an etchant containing nitric acid.

In the etching method of the present invention, the etching liquid can be applied to a semiconductor substrate containing a first layer containing Ti and a specific second layer containing germanium compound or copper, thereby preferentially dissolving the first Floor. At this time, the residue on the substrate may be cleaned and removed simultaneously with the selective etching described above. That is, the selective etching in the semiconductor substrate and the cleaning of the substrate surface can be simultaneously achieved, which contributes to a large degree of improvement in the product quality of the device, and contributes to a large degree of improvement in manufacturing efficiency. The reason for such an excellent effect is still unclear, but it is considered as follows.

An oxidizing agent such as hydrogen peroxide, which is used as a necessity in the present invention, exhibits high solubility to a specific first layer containing Ti. Further, the high reactivity of the oxidizing agent also acts on the residue and the like, and exhibits high cleaning property. In addition, the basic compound containing a specific organic amine compound, which is used as a necessity, protects the surface of the second layer containing at least one of Cu, SiO, SiN, SiOC, and SiON to suppress and prevent the oxidizing agent. The resulting etching. Further, since the oxidizing agent and the basic compound can be adjusted to have a predetermined pH environment and function, the selective etching effect and the residue cleaning effect are exhibited at a high level due to the interaction between the two. Hereinafter, the present invention will be described in detail based on preferred embodiments thereof. In the present specification, when a constituent element is listed as a metal compound such as SiOC, it is a meaning of SiO _x C _y (x, y is an arbitrary composition). However, SiO _x or the like is sometimes described and described.

[etching step]

First, the etching step of the present invention is preferred according to FIGS. 1 and 2. The embodiment will be described.

Fig. 1 is a view showing a semiconductor substrate before etching. In the manufacturing example of the present embodiment, the SiOC layer 3 and the SiON layer 2 are disposed on the tantalum wafer (not shown), and the TiN layer 1 is formed on the upper side. At this time, a via window 5 is formed on the composite layer, and a Cu layer 4 is formed on the bottom of the via window 5. The TiN layer is removed by applying the etching liquid (not shown) of this embodiment to the substrate 10 in this state. This etching liquid also has the cleaning property of the residue G generated by plasma etching, ashing, or the like, and can effectively remove the residue G. As a result, the substrate 20 in a state where the TiN film and the residue G are removed as shown in FIG. 2 can be obtained. It goes without saying that in the present invention, the etching and cleaning states as shown are ideal, but the residual of the TiN layer or the residue, or the more or less corrosion of the second layer is required according to the requirements of the manufactured semiconductor element. The quality and the like are tolerable, and the present invention is not limited by the description.

In addition, the germanium substrate or the semiconductor substrate is used in the sense of not only the germanium wafer but also the entire substrate structure in which the circuit structure is formed. The member of the substrate refers to a member constituting the above-described ruthenium substrate, and may include one material or a plurality of materials. The processed semiconductor substrate is sometimes referred to as a semiconductor substrate product, and a wafer and a processed product thereof which are further processed and divided as necessary are referred to as a semiconductor element. The orientation of the substrate is not particularly limited. In FIG. 1, the opposite side (TiN side) from the germanium wafer is referred to as "upper" or "top", and the germanium wafer side (SiOC side) is referred to. It is "down" or "bottom".

[矽 etching solution]

Next, a preferred embodiment of the ruthenium etching solution of the present invention will be described. The etching solution of this embodiment contains a specific oxidizing agent and a basic compound. Hereinafter, each component including any one will be described. In addition, in the present specification, a liquid containing a specific component includes, in addition to a liquid composition containing the component, a meaning as a kit, that is, mixing each component or a liquid, powder, or the like containing the same before use. And use.

(oxidant)

The oxidizing agent may, for example, be hydrogen peroxide, ammonium persulfate, perboric acid, peracetic acid, periodic acid, perchloric acid or a combination thereof, and among them, hydrogen peroxide is particularly preferred.

The oxidizing agent is preferably contained in an amount of 0.5% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, even more preferably 2% by mass based on the total mass of the etching liquid of the present embodiment. Mass%~10% by mass. By setting it as the said upper limit or less, it is preferable to suppress the excess etching of a 2nd layer further. It is preferable from the viewpoint of setting the above lower limit value or more to etch the first layer at a sufficient speed.

(alkaline compound)

The basic compound is not particularly limited as long as it contains an organic amine compound, and is preferably a compound having a primary amine to a quaternary amine (ammonium) in the structure. For example, an alkylamine having 1 to 6 carbon atoms, an aromatic amine having 6 to 12 carbon atoms, a secondary amine having 2 to 6 carbon atoms, a tertiary amine having 3 to 6 carbon atoms, and carbon can be cited. The number is 4 to 16 quaternary ammonium or a salt thereof, 2-aminoethanol, hydrazine carbonate, and the like.

Among them, preferred are the compounds represented by the following formula (I).

N(R) ₄ . OH.........Formula (I)

R represents a substituent. A plurality of Rs may also be different from each other. R preferably includes an alkyl group, an alkenyl group, an alkynyl group, an aryl group or an aralkyl group, and a preferred range thereof is the same as the substituent T described below. Among them, a particularly preferred compound is tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH). Moreover, it is of course no problem to use these compounds in combination.

The basic compound is preferably contained in an amount of 0.05% by mass to 50% by mass, more preferably 0.05% by mass to 20% by mass, based on the total mass of the etching liquid of the present embodiment, and more preferably It is contained in an amount of 0.5% by mass to 15% by mass, particularly preferably 0.5% by mass to 10% by mass. From the viewpoint of avoiding the problem that the basic compound itself inhibits the etching of the metal layer, it is preferably set to be equal to or less than the above upper limit. From the viewpoint of sufficiently suppressing the etching of the second layer, it is preferable to set it to the above lower limit value or more.

In terms of the relationship with the oxidizing agent, it is preferred to use 0.5 parts by mass to 50 parts by mass of the basic compound, and more preferably 10 parts by mass to 40 parts by mass, based on 100 parts by mass of the oxidizing agent. By using the amount of both in an appropriate relationship, good etching property and residue removal property can be achieved, and high etching selectivity can be achieved at the same time.

In addition, in the present specification, when the term "compound" is added to the end and is referred to by a specific name or chemical formula, it is also used in addition to the compound itself to include a salt, a complex thereof, and an ion thereof. meaning. And it also has the following meaning: within the range having the desired effect, It contains a derivative which is modified in a predetermined form. Further, in the present specification, the term "substituent" is used in the term "substituent" to mean a specific atomic group, and the substituent may have any substituent. It is also synonymous with compounds that are not indicated as substituted or unsubstituted. Preferred substituents include the following substituents T.

(substituent T)

The substituent T is an alkyl group (preferably an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a pentyl group, a heptyl group, or a 1-ethylpentyl group). , benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl (preferably an alkenyl group having 2 to 20 carbon atoms, such as a vinyl group, an allyl group, an oleyl group, etc.) , alkynyl (preferably an alkynyl group having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl, etc.), cycloalkyl (preferably having 3 to 3 carbon atoms) a cycloalkyl group of 20, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), an aryl group (preferably an aryl group having 6 to 26 carbon atoms, such as phenyl, 1) a -naphthyl group, a 4-methoxyphenyl group, a 2-chlorophenyl group, a 3-methylphenyl group or the like), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, for example, 2 Pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc.), alkoxy (preferably an alkane having 1 to 20 carbon atoms) An oxy group such as a methoxy group, an ethoxy group, an isopropoxy group or a benzyloxy group, or an aryloxy group (preferably an aryloxy group having 6 to 26 carbon atoms, such as a phenoxy group, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), alkoxycarbonyl (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, such as ethoxylated) Alkyl group, 2-ethylhexyloxycarbonyl group, etc.), an amine group (preferably an amine group having 0 to 20 carbon atoms, such as an amine group, N,N-dimethylamine a group, a N,N-diethylamino group, an N-ethylamino group, an anilino group, etc.), a sulfonylamino group (preferably a sulfonylamino group having 0 to 20 carbon atoms, such as N, N) - dimethylsulfonylamino, N-phenylsulfonamide, etc., sulfhydryl (preferably a fluorenyl group having 1 to 20 carbon atoms, such as ethyl, propyl, butyl, benzyl Sulfhydryl or the like, an anthraceneoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, such as an ethyloxy group, a benzyloxy group, etc.), an amine methyl group (preferably a carbon atom) The number is 1 to 20 aminomethyl sulfhydryl groups, such as N,N-dimethylamine carbaryl, N-phenylamine carbhydryl group, etc., fluorenylamino group (preferably, the number of carbon atoms is 1~) a mercapto group of 20, such as an ethyl decylamino group, a benzhydrylamino group, a cyano group, or a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), more preferably an alkane a base, an alkenyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an amine group, a decylamino group, a cyano group or a halogen atom, and particularly preferably an alkyl group or an alkenyl group. A heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an amine group, a decylamino group or a cyano group.

[aqueous medium]

The etching liquid of the present invention is an aqueous liquid composition in which an aqueous medium is used as a medium. The aqueous medium refers to water and an aqueous solution in which soluble solutes are dissolved in water. The solute is a meaning other than the essential component, and any component may be separately specified as needed. The solute referred to herein is, for example, a salt of an inorganic compound such as an alcohol or sodium chloride. However, in the case of applying a solute, the amount thereof is preferably controlled within a range in which the desired effect of the present invention is remarkable. Further, the above-mentioned water-based composition means that the aqueous medium is the main medium, and it is preferable that more than half of the medium other than the solid matter is an aqueous medium, more preferably 70% by mass or more, and particularly preferably 90% by mass or more.

[pH]

In the present invention, the pH of the etching solution is adjusted to 7 to 14, preferably 9 to 14, more preferably 10 to 13. By setting it as the said lower limit or more, the compound containing Ti can be etched at high speed, and it is set as the above-mentioned upper-limit- Etching is therefore preferred. Further, in the present invention, the pH is not particularly limited, and is obtained by using the apparatus and conditions for measurement in the examples.

(other ingredients) . pH adjuster

In the present embodiment, the pH of the etching solution is adjusted to the above range, and it is preferred to use a pH adjusting agent for the adjustment. The pH adjuster is a basic compound described in the above [Basic Compound] in order to increase the pH, and a mineral acid such as hydrochloric acid, nitric acid, sulfuric acid or phosphoric acid, or formic acid, acetic acid or C, in order to lower the pH. Acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methyl Caproic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid Organic acids such as phthalic acid, malic acid, tartaric acid, citric acid, and lactic acid.

The amount of the pH adjuster used is not particularly limited, and may be used in an amount necessary to adjust the pH to the above range.

Further, a water-soluble organic solvent may be further added to the ruthenium etching liquid of the present invention. The so-called water-soluble organic solvent is capable of mixing with water in any ratio. Organic solvent. This is effective in that the uniform etching property in the plane of the wafer can be further improved.

Examples of the water-soluble organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, and cyclohexane. Alcohol, sorbitol, xylitol, 2-methyl-2,4-pentanediol, 1,3-butanediol, 1,4-butanediol and other alcohol compound solvents, including alkylene glycol alkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol, polyethylene glycol, propylene glycol monomethyl ether An ether compound solvent of dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether, or the like.

Preferred among these are an alcohol compound solvent having 2 to 15 carbon atoms, an alcohol-ether compound solvent having 2 to 15 carbon atoms, and more preferably an alcohol compound having 2 or more hydroxyl groups having 2 to 10 carbon atoms. A solvent and an alcohol-ether compound solvent having a carbon number of 2 to 10 and having two or more hydroxyl groups. Particularly preferred are alkanediol alkyl ethers having a carbon number of 3-8. The water-soluble organic solvent may be used singly or in combination of two or more kinds as appropriate. Further, in the present specification, a compound having a hydroxyl group (-OH) and an ether group (-O-) in the molecule is, in principle, included in an ether compound (not referred to as an alcohol compound), and specifically has a hydroxyl group. A compound which is both an ether group and an ether group is sometimes referred to as an alcohol-ether compound.

Among them, propylene glycol and dipropylene glycol are particularly preferred. The amount of addition is preferably from 0.1% by mass to 70% by mass, and more preferably from 10% by mass to 50% by mass based on the total amount of the etching liquid. By setting the amount to be equal to or higher than the above lower limit, the uniformity of the above etching can be effectively improved.

In the present invention, it is very effective to add the above water-soluble organic solvent Agent. By this addition, the excellent selective etching effect is remarkable, and a high etching effect can be obtained in various constitutional aspects.

[etching conditions]

In the present embodiment, the conditions for performing the etching are not particularly limited, and the spray type (monolithic) etching may be a batch type (immersion type) etching. In the spray etching, the semiconductor substrate is transferred or rotated in a predetermined direction, and an etching liquid is ejected in the space to bring the etching liquid into contact with the semiconductor substrate. On the other hand, in the batch etching, the semiconductor substrate is immersed in a liquid bath containing an etching liquid, and the semiconductor substrate is brought into contact with the etching liquid in the liquid bath. These etching methods may be suitably used depending on the structure or material of the element.

As the ambient temperature for etching, in the case of a spray type, it is preferred to set the ejection space to 15 ° C to 100 ° C, and more preferably 20 ° C to 80 ° C. As for the etching liquid, it is preferably set to 20 ° C to 80 ° C, and more preferably set to 30 ° C to 70 ° C. By setting it as the said lower limit or more, it is preferable to ensure the sufficient etching rate with respect to a metal layer. By setting it as the said upper limit or less, the selectivity of etching can be ensured, and it is preferable. The supply rate of the etching liquid is not particularly limited, but is preferably 0.05 L/min to 1 L/min, more preferably 0.1 L/min to 0.5 L/min. By setting it as the said lower limit or more, it is preferable to ensure the uniformity in the surface of an etching. By setting it as the said upper limit or less, it is preferable to ensure stable selectivity at the time of continuous process. When the semiconductor substrate is rotated, it varies depending on its size, etc., and is preferably rotated at 50 rpm to 400 rpm from the viewpoint of the above.

In the case of a batch type, it is preferred to set the liquid bath to 20 ° C~ 80 ° C, more preferably set to 30 ° C ~ 70 ° C. By setting it as the said lower limit or more, it is preferable to ensure an etching speed. By setting it as the said upper limit or less, the selectivity of etching can be ensured, and it is preferable. The immersion time of the semiconductor substrate is not particularly limited, but is preferably 0.5 minutes to 30 minutes, and more preferably 1 minute to 10 minutes. By setting it as the said lower limit or more, it is preferable to ensure the uniformity in the surface of an etching. By setting it as the said upper limit or less, it is preferable to ensure stable selectivity at the time of continuous process.

[residue]

In the manufacturing process of a semiconductor element, there is a step of etching a metal layer or the like on a semiconductor substrate by plasma etching using a resist pattern or the like as a mask. Specifically, the metal layer, the semiconductor layer, the insulating layer, and the like are etched to pattern the metal layer or the semiconductor layer, or an opening such as a via hole or a wiring trench is formed in the insulating layer. In the above plasma etching, a residue derived from a resist used as a mask or a metal layer, a semiconductor layer, or an insulating layer to be etched is generated on the semiconductor substrate. In the present invention, the residue generated by plasma etching as described above is referred to as "plasma etching residue".

Moreover, the resist pattern used as a mask is removed after etching. The removal of the resist pattern can be carried out as described above: a wet method using a stripper solution, or a dry method using ashing (the ashing uses, for example, plasma, ozone, etc.). In the above ashing, a residue obtained by deterioration of the plasma etching residue generated by plasma etching or a residue derived from the removed resist is generated on the semiconductor substrate. In the present invention, the residue generated by ashing as described above is referred to as "ashing residue". Moreover, as a plasma etching residue and The general name of the residue to be cleaned and removed on the semiconductor substrate such as the ash residue may be simply referred to as "residue".

As the plasma etching residue or the ashing residue of the post-etching residue (Post Etch Residue), it is preferable to wash and remove using the cleaning composition. The etching liquid of this embodiment can also be applied as a cleaning liquid for removing the plasma etching residue and/or the ashing residue. Among them, it is preferable to remove the plasma etching residue and the ash residue after the plasma ashing after the plasma etching.

[processed object]

The material to be etched by applying the etching liquid of the present embodiment may be any one, and is applied to a semiconductor substrate including a layer including a first layer of Ti including Cu, SiO, SiN, SiOC, and SiON. At least one type of second layer. Here, SiO is a thermal oxide film containing ruthenium and SiO ₂ , and is SiOx.

. Tier 1

The first layer is preferably etched at a high etch rate, with TiN being particularly preferred. The thickness of the first layer is not particularly limited, and is substantially 0.005 μm to 0.3 μm when considering a normal element configuration. The etching rate [R1] of the first layer is not particularly limited, and is preferably 50 Å/min to 500 Å/min in consideration of production efficiency.

. Level 2

The second layer is preferably controlled to a low etch rate. The thickness of the second layer is not particularly limited, and is substantially 0.005 μm to 0.5 μm when considering a normal element configuration. The etching rate of the second layer [R2] is not particularly limited. In terms of production efficiency, it is preferably 0.001 Å/min to 10 Å/min.

In the selective etching of the first layer, the etching rate ratio ([R1]/[R2]) is not particularly limited, and it is preferably 50 or more on the premise that an element which is required to have high selectivity is used. More preferably, it is 10~5000, further better is 30~3000, and the best is 50~2500.

In the present embodiment, it is preferred to further carry out the step of etching the third layer containing W by using an etching solution containing nitric acid in combination. In other words, a semiconductor substrate including the third layer including W is prepared as the semiconductor substrate 30, and an etching liquid containing nitric acid is applied in a state where the third layer is exposed (see FIG. 3). It is sometimes referred to as the A step. In the step A of the present embodiment, the first layer containing Ti is selectively etched without etching W, and the processed substrate 40 is formed (see Fig. 4). Subsequent step B is a step of treatment using a specific etching solution comprising an oxidizing agent and a basic compound as described in detail above. Here, in the second layer, a substrate on which copper is exposed is specifically targeted (FIG. 1). In the present embodiment, the first layer is selectively etched by applying the specific etching solution here (Fig. 2).

As the above-mentioned steps A and B, any of the steps may be preceded, and if necessary, the steps A and B may be applied repeatedly to produce a semiconductor substrate having a desired morphology.

[Manufacture of semiconductor substrate products]

In the present embodiment, it is preferable to manufacture a semiconductor substrate product having a desired structure by forming a semiconductor substrate on which the first layer and the second layer are formed on a germanium wafer, and The semiconductor substrate is applied with an etching solution to selectively dissolve the first layer (B). At this time, the etching solution uses the specific etching liquid. Preferably, the semiconductor substrate is subjected to dry etching or dry ashing before the etching step, and the residue generated in the step is removed. This operation has been explained. Further, it is also possible to perform etching while using an etching solution containing nitric acid while protecting W (step A). In each step in the manufacture of a semiconductor substrate product, each processing method generally applied to such a product can also be applied.

In the above description, it is particularly preferred in the present invention to contain 0.1% to 3% of TMAH, TEAH or TPAH as a basic compound, and 2% to 10% of hydrogen peroxide as an oxidizing agent as a water-soluble organic solvent. The propylene glycol and dipropylene glycol are treated in a liquid of 10% to 50% at 30 ° C to 70 ° C. For the purpose of improving the stability of the treatment and the improvement of the yield, the treatment time is particularly preferably from 1 minute to 10 minutes. Further, the substrate containing Cu is treated under such conditions, and a combination of a method of treating a substrate containing W at a temperature of 30 ° C to 70 ° C using a nitric acid having a concentration of 50% or more is preferable as a condition for producing a semiconductor substrate product. .

[Example] <Example 1, Comparative Example 1>

The etching liquid was prepared by containing the components shown in Table 1 (mass%) shown in Table 1 below.

<etching test>

Test wafer: a semiconductor substrate on which a TiN layer, an SiOC layer, or a Cu layer for evaluation of a test is prepared in a state of being arranged on a germanium wafer (test Examination). An evaluation test was carried out by etching under the following conditions by a monolithic apparatus (SPS-Europe B.V., manufactured by POLOS (trade name)).

. Chemical solution temperature: 80 ° C

. Spray volume: 1 L/min.

. Wafer speed is 500 rpm

[Wiring of wiring]

The surface of the etched wafer was observed by SEM, and the removability of the residue (plasma etching residue and ashing residue) was evaluated.

AA: The residue is completely removed.

A: The residue is substantially completely removed.

B: a poorly dissolved substance remaining in the residue.

C: The residue was hardly removed.

[Measurement of pH]

The pH in the table is a value measured by F-51 (trade name) manufactured by HORIBA at room temperature (25 ° C).

As shown in the above table, in the comparative example, the selective etching and cleaning properties of TiN could not be achieved. On the other hand, the ruthenium etching solution (samples 101 to 140) of the present invention exhibits a high etching rate for TiN, and exhibits high etching selectivity without causing damage to SiOC and Cu. Further, the dry etching residue is excellent in removability, and the manufacturing quality and manufacturing efficiency (productivity) of the semiconductor substrate having a specific structure can be greatly improved.

<Example 2>

A substrate in which a metal layer and a ruthenium compound layer shown in Table 2 were placed in addition to TiN, SiOC, and Cu was prepared, and etching was performed in the same manner as in Test 124 (Test 201). The results are shown in the upper table of Table 2, and the etching selection ratios are collectively shown in the table below Table 2 together with the results of TiN, SiOC, Cu, and SiOx described above.

<Example 2A>

The evaluation liquid 124 was changed in temperature and evaluated. The selection ratios are summarized in the table below Table 2A.

As shown in the above table, according to the present invention, it is understood that a good etching rate and selectivity are obtained in a predetermined combination among TiN/SiOC and TiN/Cu. It was confirmed that a particularly high selectivity was not obtained for SiOx.

<Example 3>

As described below, an etching test using a nitric acid etching solution and a combination of the above-described specific etching liquid containing hydrogen peroxide and a basic compound is performed.

First, 69% by mass of concentrated nitric acid was prepared. Etching using the concentrated nitric acid was carried out in the same manner as in Example 1 except that the wafer including the W layer was used instead of the Cu layer. The etching speed of W, SiON, and SiOC is approximately 0 Å/min. On the other hand, it was confirmed that TiN was selectively etched at a rate of 100 Å/min. In addition, the etching property of concentrated nitric acid was similarly confirmed about the Cu layer, and as a result, it was found that an extremely high etching rate of about 1,000 Å/min to 5,000 Å/min was exhibited.

Further, after the chemical liquid (124) used in Example 1 and nitric acid were used to form a three-layer structure of the first layer (Cu), the second layer (W), and the third layer (Cu), the treatment was carried out. As a result of evaluation of the electrical characteristics of the wafer, problems such as an increase in the resistance value and insulation were not observed in the evaluation of the electrical characteristics of the wirings. From this, it is understood that an element having a W electrode and a Cu electrode can be suitably produced by a combination of a nitric acid etching solution and the specific etching liquid.

1‧‧‧TiN layer

2‧‧‧SiON layer

3‧‧‧SiOC layer

4‧‧‧Cu layer

5‧‧‧layer window

10, 20, 30, 40‧‧‧ substrates

14‧‧‧W layer

G‧‧‧ residue

Fig. 1 is a cross-sectional view schematically showing an example of a manufacturing process (before etching) of a semiconductor substrate in an embodiment of the present invention.

Fig. 2 is a cross-sectional view schematically showing an example of a manufacturing step (after etching) of a semiconductor substrate in an embodiment of the present invention.

Fig. 3 is a cross-sectional view schematically showing another example of the manufacturing steps (before etching) of the semiconductor substrate in the embodiment of the present invention.

4 is a cross-sectional view schematically showing another example of the manufacturing steps (after etching) of the semiconductor substrate in the embodiment of the present invention.

Claims (16)

An etching method for applying a specific etching liquid to a semiconductor substrate including a first layer containing Ti and a second layer containing at least one of Cu, SiO, SiN, SiOC, and SiON to select the first layer The method of etching is characterized in that the specific etching liquid contains a basic compound containing an organic amine compound and an oxidizing agent in an aqueous medium, and has a pH of 7 to 14. The etching method according to claim 1, wherein the basic compound is a compound represented by the following formula (I): N(R) ₄ . OH... Formula (I) (R represents a substituent; a plurality of R may be different from each other). The etching method according to claim 1 or 2, wherein the basic compound is tetramethylammonium hydroxide, tetraethylammonium hydroxide or tetrapropylammonium hydroxide. The etching method according to claim 1, wherein the oxidizing agent is hydrogen peroxide, ammonium persulfate, perboric acid, peracetic acid, periodic acid, perchloric acid or a combination thereof. The etching method according to claim 1, wherein a ratio (R1/R2) of the etching rate (R1) of the first layer to an etching rate (R2) of the second layer is 30 or more. The etching method according to claim 1, wherein The semiconductor substrate includes a third layer including W, and the third layer is exposed, and the first layer is selectively etched by using an etching solution containing nitric acid, and the copper of the second layer is exposed. The first layer is selectively etched by applying the specific etchant. The etching method according to claim 1, wherein the etching is performed in a range of from 20 ° C to 80 ° C. An etchant which selectively etches a first layer containing Ti with respect to a second layer containing at least one of Cu, SiO, SiOC, and SiON, and contains an organic solvent in an aqueous medium. The basic compound of the amine compound and the oxidizing agent have a pH of 7 to 14. The etching solution according to claim 8, wherein the ratio (R1/R2) of the etching rate (R1) of the first layer to the etching rate (R2) of the second layer is 30 or more. The etching solution according to claim 8, wherein the concentration of the basic compound is 0.05% by mass to 50% by mass. The etching solution according to claim 8, wherein the concentration of the oxidizing agent is 0.5% by mass to 20% by mass. The etching solution according to claim 8, which further comprises a water-soluble organic solvent. The etching solution according to claim 12, wherein the water-soluble organic solvent is a diol compound. A kit for etching liquid, which is a kit for combining an etchant as described in claim 8 of the patent application with an etchant containing nitric acid. The semiconductor substrate includes a third layer including W. The third layer is exposed, and the first layer is selectively etched by using the etching solution containing nitric acid, and the copper of the second layer is exposed. The first layer is selectively etched by applying the specific etching solution. A method for producing a semiconductor substrate product, comprising the steps of: preparing a semiconductor substrate comprising a first layer containing Ti, and a second layer containing at least one of Cu, SiO, SiN, SiOC, and SiON; And a step of selectively etching the first layer by applying a specific etching liquid to the semiconductor substrate; the specific etching liquid is used in an aqueous medium containing a basic compound containing an organic amine compound and an oxidizing agent, and the pH thereof is 7~14 etching solution. The method for producing a semiconductor substrate according to claim 15, wherein the semiconductor substrate further includes a semiconductor substrate including a third layer of W, and the nitrile is contained in a state in which the third layer is exposed. The first layer is selectively etched by the etching liquid, and the first layer is selectively etched by applying the specific etching liquid while the copper of the second layer is exposed.