COMPOSITION AND PROCESS FOR ELECTIVELY ETCHING A HARD MASK AND/OR AN ETCH-STOP LAYER IN THE PRESENCE OF LAYERS OF LOW-K MATERIALS, COPPER, COBALT AND/OR TUNGSTEN

Abstract

Described herein is a method of using a cleaning composition in combination with one or more oxidants for removing post-etch or post-ash residue from the surface of a semiconductor substrate and/or for oxidative etching or partially oxidative etching of a layer or mask. Also described herein is the cleaning composition and a method of using the cleaning composition for removing post-etch or post-ash residue from the surface of a semiconductor substrate. Also described herein is a wet-etch composition including the cleaning composition and one or more oxidants as well as a method of using the wet-etch composition. Also described herein are a process for the manufacture of a semiconductor device from a semiconductor substrate and a kit including the cleaning composition and one or more oxidants.

Claims

1. A method of using a cleaning composition comprising at least the following components: (A) as solubilizer, one or more compounds of formula I: ##STR00007## wherein R.sup.1 is selected from the group consisting of branched and unbranched alkyl having 1, 2, 3 or 4 carbon atoms; (B) one or more corrosion inhibitors, selected from the group consisting of benzotriazoles which are unsubstituted or substituted once or twice independently by branched or unbranched alkyl having 1, 2, 3 or 4 carbon atoms, aminoalkyl wherein the alkyl is branched or unbranched and has 1, 2, 3 or 4 carbon atoms, phenyl, thiophenyl, halogen, hydroxy, nitro and/or thiol, and mixtures thereof; (C) one or more polar, non-protogenic organic solvents wherein the one, or at least one of the more, or all of the more, polar, non-protogenic organic solvents (C) are selected from the group consisting of an alkyl sulfone compound of formula IV: ##STR00008## wherein R.sup.5 is a branched or unbranched alkyl group having 1 to 5 carbon atoms, R.sup.6 is a branched or unbranched alkyl group having 1 to 5 carbon atoms, or R.sup.5 and R.sup.6 together form a branched or unbranched alkylene group having 3 to 5 carbon atoms, wherein one or two carbon atoms of said alkylene group can independently be substituted by —O—R.sup.7, wherein R.sup.7 is a branched or unbranched alkyl group having 1 to 4 carbon atoms; dimethyl formamide, dimethyl sulfoxide, dimethyl acetamide, N-methylpyrrolidone, propylene carbonate, tetrahydrofuran, 2-imidazolidinone which is substituted once or twice by a branched or unbranched alkyl group having 1 to 4 carbon atoms and mixtures thereof; and (D) water, the method comprising using the cleaning composition in combination with one or more oxidants, wherein the one or more oxidants are selected from the group consisting of hydrogen peroxide, peroxide urea, peroxydisulfuric acid, ammonium persulfate, peroxymonosulfuric acid, pyrosulfuric acid, ozone and mixtures thereof for removing post-etch or post-ash residue from the surface of a semiconductor substrate and/or for etching or partially etching of a layer or mask comprising or consisting of a material selected from the group consisting of Ti, TiN, Ta, TaN, Al and HfO.sub.x and/or a layer or mask comprising or consisting of a material selected from the group consisting of tungsten carbide and tungsten nitride.

2. The method of use according to claim 1, wherein the one, or at least one of the more, or all of the more, polar, non-protogenic organic solvents (C) is an alkyl sulfone compound of formula IV.

3. The method of use according to claim 1, wherein the cleaning composition further comprises: (F) a buffering system which is suitable to buffer the pH of the cleaning composition in the range of from 6 to 9; and/or (G) one or more chelating agents, and/or (H) one or more surfactants.

4. The method of use according to claim 1, wherein in the cleaning composition the one or at least one of the more solubilizers (A) is or comprises 4-methylmorpholine-4-oxide, and/or the one or at least one of the more corrosion inhibitors (B) is selected from the group consisting of benzotriazoles which are unsubstituted or substituted once or twice independently by branched or unbranched alkyl having 1, 2, 3 or 4 carbon atoms and/or by halogen, and mixtures thereof; and/or the one or at least one of the more polar, non-protogenic organic solvents (C) is selected from the group consisting of dimethyl formamide, dimethyl sulfoxide, dimethyl acetamide, N-methylpyrrolidone, propylene carbonate, sulfolane, tetrahydrofuran and mixtures thereof, and/or the total amount of etchants comprising fluoride anions is <0.001 mass-%, relative to the total mass of the cleaning composition.

5. The method of use according to claim 1, wherein in the cleaning composition the total amount of the one or more solubilizers (A) is in the range of from 1 mass-% to 15 mass-%, relative to the total mass of the cleaning composition, and/or the total amount of the one or more corrosion inhibitors (B) is in the range of from 0.1 mass-% to 6 mass-% relative to the total mass of the cleaning composition; and/or the total amount of the one or more polar, non-protogenic organic solvents (C) is in the range of from 1 mass-% to 50 mass-% relative to the total mass of the cleaning composition; and/or the one, or at least one of the more, or all of the more, polar, non-protogenic organic solvents (C) is an alkyl sulfone compound of formula IV and the total amount of the one or more polar, non-protogenic organic solvents (C) is in the range of from 10 mass-% to 50 mass-% relative to the total mass of the cleaning composition; and/or the cleaning composition comprises at least the components (A), (B), (C), (D) and (F) and/or water (D) makes up the balance to 100 mass-% of the cleaning composition.

6. The method of use according to claim 1, wherein the method of use comprises removing post-etch or post-ash residue from the surface of a semiconductor substrate and wherein the semiconductor substrate comprises at least one material selected from the group consisting of copper, cobalt, tungsten, and a low-k material, and/or the method of use comprises cleaning a semiconductor substrate comprising at least one material selected from the group consisting of copper, cobalt, tungsten, and a low-k material; and/or the method of use comprises removing post-etch or post-ash residue from the surface of a semiconductor substrate in the presence of at least one material selected from the group consisting of copper, cobalt, tungsten, and a low-k material, wherein the post-etch or post-ash residue comprises one or more residues selected from the group comprising or consisting of one or more organic compounds, comprising or not comprising fluorine, metal organic complexes and metallic materials; and/or the method of use comprises removing residues and contaminants from the surface of a semiconductor substrate comprising at least one material selected from the group consisting of copper, cobalt, tungsten, and a low-k material.

7. The method of use according to claim 1, wherein the method of use comprises etching or partially etching a layer or mask, comprising or consisting of a material selected from the group consisting of Ti, TiN, Ta, TaN, Al and HfO.sub.x and/or a layer or mask selected from the group comprising or consisting of a material selected from the group consisting of tungsten carbide (WC.sub.x) and tungsten nitride (WN.sub.x), wherein the etching or partially etching of a layer or mask comprises removing or partially removing a metal-containing hard mask, and/or etching, in the presence of at least one material selected from the group consisting of copper, cobalt, tungsten, and a low-k material, on the surface of a semiconductor substrate; and/or etching a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising tungsten and/or a layer comprising copper and/or cobalt; and/or removing from a semiconductor substrate a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising tungsten and/or a layer comprising copper and/or cobalt, and/or removing from the surface of a semiconductor substrate a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising tungsten and/or a layer comprising copper and/or cobalt.

8. The method of use according to claim 1, wherein the cleaning composition is used in combination with the one or more oxidants in a one-step-process of removing (i) a metal-containing hard mask, and (ii) an etch-stop layer of an aluminium compound deposited on a layer comprising copper and/or on a layer comprising cobalt; and/or the cleaning composition is used in combination with the one or more oxidants in a separate step or simultaneously in the same step; and/or the one or more oxidants are used in a total amount in the range of from 2 mass-% to 25 mass-%, relative to the total mass of the cleaning composition; and/or one or more stabilizers are used in combination with the one or more oxidants and/or in combination with the cleaning composition.

9. A cleaning composition, as defined in claim 1, wherein the cleaning composition comprises (F) a buffering system which is suitable to buffer the pH of the cleaning composition in the range of from 6 to 9, and wherein the total amount of etchants comprising fluoride anions is <0.001 mass-%, relative to the total mass of the cleaning composition.

10. A method of using the cleaning composition according to claim 9, the method comprising using the cleaning composition for removing post-etch or post-ash residue from the surface of a semiconductor substrate.

11. A wet-etch composition comprising (W1) a cleaning composition as defined in claim 1, and (W2) one or more oxidants selected from the group consisting of hydrogen peroxide, peroxide urea, peroxydisulfuric acid, ammonium persulfate, peroxymonosulfuric acid, pyrosulfuric acid and ozone.

12. A method of using the wet-etch composition according to claim 11, the method comprising use the wet-etch composition for removing or partially removing a metal-containing hard mask, and/or etching, or partially etching of a layer or mask, comprising or consisting of a material selected from the group consisting of Ti, TiN, Ta, TaN, Al and HfO.sub.x and/or a layer or mask comprising or consisting of a material selected from the group consisting of tungsten carbide (WC.sub.x) and tungsten nitride (WN.sub.x), and/or etching a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt and/or a layer comprising tungsten; and/or removing from a semiconductor substrate a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt and/or preferably a layer comprising tungsten; and/or removing from the surface of a semiconductor substrate a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt and/or a layer comprising tungsten; and/or removing post-etch or post-ash residue from the surface of a semiconductor substrate.

13. A process for the manufacture of a semiconductor device from a semiconductor substrate, comprising the following steps P1) preparing a wet-etch composition by mixing a cleaning composition according to claim 1, with one or more oxidants selected from the group consisting of hydrogen peroxide, peroxide urea, peroxydisulfuric acid, ammonium persulfate, peroxymonosulfuric acid, pyrosulfuric acid, ozone and mixtures thereof, and P2) contacting at least once with the wet-etch composition received or provided in step P1), a layer or hard mask on the surface of a semiconductor substrate, and/or an etch-stop layer comprising or consisting of one or more aluminium compounds deposited on a layer comprising copper and/or on a layer comprising cobalt on the surface of a semiconductor substrate.

14. A kit comprising as separate components: (K1) a cleaning composition according to claim 1; and (K2) one or more oxidants selected from the group consisting of hydrogen peroxide, peroxide urea, peroxydisulfuric acid, ammonium persulfate, peroxymonosulfuric acid, pyrosulfuric acid, ozone and mixtures thereof; and further optionally comprising, as separate component or combined with component (K1) and/or with component (K2): (K3) one or more stabilizers.

15. A process for the manufacture of a semiconductor device from a semiconductor substrate, comprising the following steps P1) providing a wet-etch composition according to claim 11, and P2) contacting at least once with the wet-etch composition received or provided in step P1), a layer or hard mask on the surface of a semiconductor substrate, and/or an etch-stop layer comprising or consisting of one or more aluminium compounds deposited on a layer comprising copper and/or on a layer comprising cobalt on the surface of a semiconductor substrate.

16. The method of use according to claim 1, wherein the one, or at least one of the more, or all of the more, polar, non-protogenic organic solvents (C) is an alkyl sulfone compound of formula IV selected from the group consisting of ethyl methyl sulfone, ethyl isopropyl sulfone, ethyl isobutyl sulfone, isopropyl isobutyl sulfone, sulfolane, 3-methoxy sulfolane and mixtures thereof.

17. The method of use according to claim 1, wherein the cleaning composition further comprises: (F) a buffering system which is suitable to buffer the pH of the cleaning composition in the range of from 7 to 8.5.

18. The method of use according to claim 1, wherein the cleaning composition further comprises: (G) one or more chelating agents in a total amount in the range of from 0.01 mass-% to 3 mass-% relative to the total mass of the cleaning composition.

19. The method of use according to claim 1, wherein the cleaning composition further comprises: (H) one or more fluorosurfactants.

20. The method of use according to claim 1, wherein in the cleaning composition the one or at least one of the more polar, non-protogenic organic solvents (C) is dimethyl sulfoxide or sulfolane.

Description

EXAMPLES

[0433] The following examples are meant to further explain and illustrate the present invention without limiting its scope.

[0434] The following abbreviations are used in the Examples section:

*: also acting as weak acid component of buffering system (F)
5-Me-BTA: 5-methyl-benzotriazole (as defined above)
b: balance (to 100 mass-%)
BTA: benzotriazole (unsubstituted)
BDG: butyl diglycol
BTG: butyl triglycol
CDTA: 1,2-cyclohexylenedinitrilotetraacetic acid
DGMHE: diethylene glycol monohexyl ether
DGMME: diethylene glycol monomethyl ether
DIA: 1,3-dimethyl-2-imidazolidinone
DiAHP: diammonium hydrogen phosphate
DMSO: dimethyl sulfoxide
EDTMP: N,N,N,N-ethylenediaminetetrakis(methylenephosphonic acid)
EGMBE: ethylene glycol monobutyl ether
EIS: ethyl isopropyl sulfone
NMMO: 4-methylmorpholine-4-oxide
ST: surface tension (in mN/m)
TEAH: tetraethyl ammonium hydroxide
TMAH: tetramethyl ammonium hydroxide
n.a.: no data available

Example 1: Preparation of Cleaning Compositions According to the Invention

[0435] The following cleaning compositions according to the invention (CCI1 to CCI7 and CCI 8 to CCI15) were prepared by mixing the components (A) to (H) in each case (as applicable). Details are given below in tables 1a and 1b. The indication of components (A) to (H) corresponds to the indication of components as defined above.

TABLE-US-00001 TABLE 1a Cleaning compositions CCI1 to CCI7 according to the invention Cleaning Compositions [mass-%] Component Constituent CCI1 CCI2 CCI3 CCI4 CCI5 CCI6 CCI7 (A) NMMO 10-13 7-9 7-9 7-9 7-9 7-9 1-4 (B) 5-Me-BTA 0.8-1.3 0.4-0.7 0.4-0.7 0.4-0.7 0.7-1.1 0.4-0.7 0.4-0.7 (B) BTA 1.8-2.1 0.4-0.7 0.4-0.7 0.4-0.7 0.7-1.1 0.4-0.7 0.4-0.7 (C) DMSO 0 0  8-11  8-11 7-9  8-11  8-11 (C) Sulfolane 32-36 0 0 0 0 0 0 (D) Water 43-47 48-52 24-27 48-52 46-51 39-42 48-52 (E) BDG 0 0 52-57 28-31 0 0 19-22 (E) BTG 0 0 0 0 0 38-41 0 (E) EGMBE 0 38-41 0 0 0 0 0 (E) DGMHE 0 0 0 0 0 0 12-16 (E) DGMME 0 0 0 0 31-34 0 0 (F) H.sub.3PO.sub.4 0 0 0 0 0 0.1-0.3 0 (F) TEAH 0.3-0.6 0.3-0.6 0.3-0.6 0.5-0.7 0.5-0.7 0.3-0.6 0.3-0.6 (G) CDTA* 0.25-0.4  0.25-0.4  0.25-0.4  0.25-0.4  0.25-0.4  0.25-0.4  0.25-0.4  (G) EDTMP* 0 0 0 0.05-0.12 0.05-0.12 0 0 (H) Fluorosurfactant 0.02-0.05 0 0 0 0 0 0 pH 7.7 n.a. n.a. 7.7 7.8 n.a. n.a. ST 52 29 33 34 34 34 34

TABLE-US-00002 TABLE 1b Cleaning compositions CCI8 to CCI15 according to the invention Cleaning Compositions [mass-%] Component Constituent CCI8 CCI9 CCI10 CCI11 CCI12 CCI13 CCI14 CCI15 (A) NMMO 10-13 10-13 10-13 10-13 10-13 10-13 10-13 10-13 (B) 5-Me-BTA 0.7-1.1 0.7-1.1 0.7-1.1 0.7-1.1 0.5-0.8 0.5-0.8 0.5-0.8 0.7-1.1 (B) BTA 1.6-1.9 1.6-1.9 1.6-1.9 1.6-1.9 0.5-0.8 0.5-0.8 0.5-0.8 1.6-1.9 (C) DMSO 0 0 0  9-11  9-11 0 0 0 (C) Sulfolane 32-36 0 0 0 0 0 32-36 0 (C) EIS 0 32-36 0 0 0 0 0 0 (C) DIA 0 0 0 0 0 0 0  9-11 (D) Water b b b b b b b b (E) BDG 0 0 32-36 32-36 28-32 28-32 0 32-36 (F) DiAHP 0 0 0 0 0.5-1.5 0 0 0 (F) TMAH 0.7-1.3 0.7-1.3 0.7-1.3 0.7-1.3 0 0.3-0.6 0.3-0.6 0.7-1.3 (G) CDTA* 0.2-0.4 0.2-0.4 0.2-0.4 0.2-0.4 0.2-0.4 0.2-0.4 0.2-0.4 0.2-0.4 (H) Fluorosurfactant 0.01-1.0  0.01-1.0  0 0 0 0.01-1.0  0.01-1.0  0 pH 7.5 n.a. n.a. n.a. n.a. n.a. n.a. n.a.

Example 2: Preparation of Wet-Etch Compositions According to the Invention

[0436] The following wet-etch compositions according to the invention (WEI1 to WEI7, WEI8 to WEI11 and WEI15) were prepared by mixing the cleaning compositions of the invention CCI1 to CCI7, or CCI8 to CCI11, or CCI15, respectively (see Example 1), in each case with hydrogen peroxide (H.sub.2O.sub.2, 31% in water) in a sufficient amount to receive the final concentrations or mass ratios as shown in tables 2a and 2b below, where the “mass-% H.sub.2O.sub.2” in each case is given in relation to the total mass of the respective cleaning composition (CCI1 to CCI7, CCI8 to CCI11 and CCI15) utilized for preparing a certain wet-etch composition and where the “mass-% H.sub.2O.sub.2” in each case represents the amount or concentration of pure (undiluted) hydrogen peroxide present in the respective wet-etch composition.

TABLE-US-00003 TABLE 2a Wet-etch compositions WEI1 to WEI7 Wet-etch Compositions WEI1 WEI2 WEI3 WEI4 WEI5 WEI6 WEI7 Cleaning composition: CCI1 CCI2 CCI3 CCI4 CCI5 CCI6 CCI7 H.sub.2O.sub.2 (pure 15-17 15-17 15-17 15-17 15-17 15-17 15-17 undiluted) [mass.-%]/ cleaning composition pH: 6.9 6.9 6.9 6.9 6.9 6.9 6.9

TABLE-US-00004 TABLE 2b Wet-etch compositions WEI8 to WEI11 and WEI15 Wet-etch Compositions WEI8 WEI9 WEI10 WEI11 WEI15 Cleaning composition: CCI8 CCI9 CCI10 CCI11 CCI15 H.sub.2O.sub.2 (pure, 15-17 15-17 15-17 15-17 15-17 undiluted) [mass.-%]/ cleaning composition pH: 7.5 7.5 7.5 7.5 7.5

Example 3: Measurement of Etch Loss on TiN

[0437] The etch losses on layers of TiN caused by wet-etch compositions of the invention from Example 2 were determined according or analogous to methods described in document WO 2015/173730 A1. The wet-etch compositions were prepared by mixing the respective cleaning composition with the specified amount of hydrogen peroxide immediately before the etch-rate experiments were performed.

[0438] Si test wafers with layers of TiN (thicknesses of TiN layers were in the range of from 200 to 300 nm as physical vapour deposited TiN, “PVD TiN”) were selected from appropriate commercial sources and broken into smaller coupons. The layer thicknesses and etch rates were then measured by X-ray fluorescence analysis (XRF) in a manner known per se. XRF is suitable for the non-contact and non-destructive thickness measurement of thin layers as well as for determining their chemical composition. For this type of measurement, the X-ray source and detector are located on the same side of a sample. When the layer on the substrate is subjected to X-rays, the radiation will penetrate the layer, if it is sufficiently thin, to a certain extent, depending on the thickness, and in turn cause characteristic fluorescence radiation in the material of the underlying substrate. On its way to the detector, this fluorescence radiation will be attenuated by absorption at the layer. The thickness of the layer can be determined based on the intensity attenuation of the fluorescence radiation of the substrate material.

[0439] For determining the initial film or layer thickness of the applicable material, an XRF recipe was created for the pristine wafers, based on reported layer thickness from the supplier and verified with transmission electron microscopy (TEM) cross-section.

[0440] The wet-etch compositions were then brought to the test temperature (59° C. for experiments of this Example 3) and stirred mechanically. The wafer coupons were fixed to a mechanical holder and were contacted with the wet-etch compositions for the reaction time (1 minute for experiments of this Example 3) in a beaker. Subsequently, the coupons were withdrawn from the wet-etch compositions and cleaned with ultra-pure water or with isopropyl alcohol or with a mixture of ultra-pure water and isopropyl alcohol, for a period of about 1 minute. Afterwards, the coupons were dried with nitrogen gas. The residual thickness of the TiN layers after etching was measured again as described above and the etch loss was calculated by subtracting the layer thickness after contact with the wet-etch composition from the thickness of the same layer before contact with the test composition. The results from this test (etch loss of TiN layer) are shown in table 3 below. All values for etch losses measured in examples 3 to 5 are given in Å, unless stated otherwise.

Example 4: Measurement of Etch Loss on Aluminium Oxide (AlOx), Cobalt and Copper

[0441] Si wafers or wafer pieces (collectively referred to as “test wafers” in the following) with the appropriate types of outer layers (the thicknesses of Co layers were in the range of from 25 to 200 nm; the thicknesses of AlO.sub.x layers were about 20 nm; all outer layers relevant for performing the etch loss experiments were thick enough to allow obtaining meaningful measurement results post etch treatment) were obtained from commercial sources. The test wafers were pre-treated as applicable: Cu and Co were each immersed into an oxalic acid solution for 20-30 s and then rinsed with water and dried. AlO.sub.x-coated surfaces were not pre-treated.

[0442] Aluminium oxide (AlO.sub.x)-coated surfaces were used as a representative model for layers comprising or consisting of one or more aluminium compounds (as defined above).

[0443] The wet-etch compositions (see Example 2 and table 2 above) were prepared and the test wafers (see above) were contacted with the wet-etch compositions in a glass beaker, at a temperature of 59° C. and for a reaction time period of 10 min in the case of AlO.sub.x surfaces and Cu surfaces and for a reaction time period of 5 min in the case of cobalt surfaces, and then withdrawn from the wet-etch compositions, rinsed with water or isopropanol and dried with nitrogen gas.

[0444] The thicknesses of the copper, cobalt and aluminium oxide layers on the test wafers were determined before and after contact with the test compositions by X-ray fluorescence analysis (as explained in Example 3 above). Experiments were performed at least three times to ensure reproducibility.

[0445] The difference of the measured value of the thickness of a copper, cobalt or AlO.sub.x-layer, respectively, before its contact with a wet-etch composition, minus the measured value of the thickness of the same copper, cobalt or AlO.sub.x-layer, respectively, after its contact with the wet-etch composition was determined in each case as the resulting etch loss of the respective layer (as explained in Example 3 above). The results from this test (etch loss of Cu-, Co- or AlO.sub.x-layer, respectively) are shown in table 3 below (each given value in table 3 representing the average of at least three experiments).

Example 5: Measurement of Etch Loss on Subjacent Tungsten Layers

[0446] Si test wafers with consecutive layers of (i) low-k material (top layer, layer thickness 75 Å), (ii) etch-stop layer consisting of one or more aluminium compounds (AlO.sub.x-layer, as first subjacent layer under top layer, layer thickness 50 Å) and (iii) tungsten (“subjacent W”) layer (layer comprising tungsten metal, layer thickness 1500 Å, as second subjacent layer under the first subjacent layer and placed on the surface of a Si test wafer), were prepared. The Si test wafer stacks so prepared and comprising (in the given order) (i) the low-k material layer, (ii) the etch-stop layer, (iii) the tungsten layer and (iv) the surface of the Si test wafer were sealed at all sides in a way that a wet-etch composition applied to the top layer (i) of the stacks (as done in the present experiment) could only get in contact with the tungsten layer (iii) by passing (penetrating or diffusing) through (i) the top layer and through (ii) the etch-stop layer (first subjacent layer).

[0447] The Si test wafer stacks were then etched by contacting them with wet-etch compositions prepared according to Example 2 above in an etch-process equivalent to the etch-process as described in Example 3 above (applicable test temperature in this example 5: 59° C., applicable reaction time in this example 5: 1 minute). The thickness of the tungsten layer before and after etching was then determined according to the method as explained in Example 3 above and the respective etch loss of the tungsten layer was calculated as explained in Example 3. The results from this test are shown in table 3 below.

TABLE-US-00005 TABLE 3 Results from etch tests on subjacent tungsten layers with wet-etch compositions according to the invention Etch loss of Wet-etch Composition of the Invention layer [Å]: WEI1 WEI2 WEI3 WEI4 WEI5 WEI6 WEI7 TiN 102 n.a. n.a. 105 105 n.a. n.a. Cu 15 n.a. n.a. 16 14 n.a. n.a. Co 2.6 n.a. n.a. 2 2 n.a. n.a. AlO.sub.x 5 n.a. n.a. 1 2 n.a. n.a. Subjacent W 15 22 18 6 4 4 6

[0448] From the results shown in table 3 above it can be seen that at least wet-etch compositions WEI1, WEI 4 and WEI5 had excellent etch rate selectivities for TiN (for selectively etching hard masks comprising or consisting of TiN) and AlOx (for selectively removing etch-stop-layers comprising or consisting of one or more aluminium compounds), Cu (for preserving any copper present in the etching step to the highest possible extent) and Co (for preserving any copper present in the etching step to the highest possible extent). It can therefore be concluded that all wet-etch compositions WEI1 to WEI7 are suited for application in manufacturing processes for 10 nm structures or sub-10 nm structures, e.g. for 7 nm structures, on a semiconductor substrate, including in 1-step threefold removal steps of said processes as explained above.

[0449] It can further be seen from the results shown in table 3 above that wet-etch compositions WEI4, WEI5, WEI6 and WEI7 according to the present invention (all showing beneficial etch losses on subjacent W layers of <10 nm under the test conditions of Example 5) are in addition excellently suited for application in manufacturing processes for 7 nm structures or sub-7 nm structures, e.g. for 5 nm structures, on a semiconductor substrate, including in 1-step threefold removal steps of said processes as explained above.

Example 6: Measurement of Etch Loss on TiN as a Function of Age of Wet-Etch Compositions

[0450] Similar as in Example 3 above, the etch losses of TiN caused by wet-etch compositions WEI8 to WEI11 and WEI15 of the invention from Example 2 above (see table 2b) were determined according or analogous to methods described in document WO 2015/173730 A1.

[0451] In the present Example 6, Si test wafers (12 inch) with layers of TiN (thickness of TiN layers about 300 nm as PVD TiN) were loaded into 100 mL of the wet-etch compositions as specified in table 4 below and held therein at a temperature of 60° C. in each case for time intervals as also specified in table 4 below. After each time interval, the remaining thickness of the TiN layer on a test wafer was determined as explained in Example 3 above, and compared to the thickness of the TiN layer of the same test wafer at the beginning of the experiment. The remaining activity of a wet-etch compositions tested in this experiment after a certain time interval is then given in the format of an etch rate in Ångstrom/min (Å/min), as is common in the field. The results of this experiment are shown in table 4 below (figures shown in table 4 are within the precision of measurement of the method applied).

TABLE-US-00006 TABLE 4 Results from etch tests on TiN layers with wet-etch compositions according to the invention as a function of age of wet-etch composition Time interval after Wet-etch Compositions start of experiment WEI8 WEI9 WEI10 WEI11 WEI15 Etch rate: Etch rate [Å/min] Start (wet-etch 150 153 151 153 123 composition freshly prepared) 1.5 hrs 150 153 150 152 120 3.5 hrs 149 153 154 146 122 5.5 hrs 150 153 130 138 123 7.5 hrs 152 154 100 103 129  12 hrs 153 155 78 58 115  24 hrs 155 158 54 39 108

[0452] From the results shown in table 4 above it can be seen that a wet-etch composition according to the invention, in particular when comprising as polar, non-protogenic organic solvent (C) (only) an alkyl sulfone compound of formula IV, more in particular when comprising as polar, non-protogenic organic solvent (C) sulfolane or ethyl isopropyl sulfone, (but no alkyl glycol ether (E)) provides stable etch rates for TiN layers over extended time periods. In the present experiment, the etch rate of such wet-etch compositions according to the invention (see e.g. WEI8 and WEI 9) performed on a TiN layer was stable and did not decrease (within the measuring accuracy of the test method) for a period of at least 24 hours.

[0453] From the results shown in table 4 above it can also be seen that wet-etch compositions comprising one or more alkyl glycol ethers (E) (but no polar, non-protogenic organic solvent (C)) as defined herein, provided stable etch rates for TiN layers over somewhat shorter time periods.

[0454] From the results shown in table 4 above, it can further be seen that wet-etch compositions comprising one or more alkyl glycol ethers (E) and a polar, non-protogenic organic solvent (C) as defined herein, but no alkyl sulfone compound of formula IV as defined herein, provided stable etch rates for TiN layers over somewhat shorter time periods.

[0455] In addition, it can be seen from the results shown in table 4 above that the etch rate of wet-etch compositions comprising one or more alkyl glycol ethers (E) as defined herein and as a polar, non-protogenic organic solvent (C) as defined herein 1,3-dimethyl-2-imidazolidinone (but no alkyl sulfone compound of formula IV as defined herein, see e.g. WEI15) showed etch rates for TiN layers at a level nearly comparable to the level of a wet-etch composition comprising as polar, non-protogenic organic solvent (C) an alkyl sulfone compound of formula IV, for a period of at least 24 hours.

Example 7: Measuring of Particle Count in the Nanometer to Micrometer Range in Cleaning Compositions

[0456] Cleaning compositions CCI12, CCI13 and CCI14 were prepared (200 mL each) as explained in Example 1 above and filtered. Subsequent to filtration, the amount of liquid particles of particle sizes of 0.15 μm, 0.2 μm, 0.3 μm and 0.5 μm were determined by means of a liquid-borne particle counter (Rion KS 40 A or Rion KS 19 F, Rion Co., Ltd., JP).

[0457] It was found in this experiment that cleaning composition CCI14 comprised the lowest amount of particles in all particle size categories (see above), followed by cleaning composition CCI13 and then cleaning composition CCI12. From this result it can be concluded that cleaning composition CCI14 (comprising as polar, non-protogenic organic solvent (C) an alkyl sulfone compound of formula IV (sulfolane)), had the most beneficial inhibitory effect on particle aggregation of the cleaning compositions tested.

Example 8: Measuring of Particle Count in the Nanometer to Micrometer Range on the Surface of a Semiconductor Substrate

[0458] Cleaning compositions according to the present invention were prepared (see Example 1 above) and applied to the surfaces of full 300 mm non-patterned wafer (SiO surface). The wafers were then fully processed, including rinsing and drying. Subsequently, the surfaces of the processed wafers were inspected with a commercial unpatterned wafer surface inspection system (KLA Tencor Corp., USA: Surfscan® SP3, SP5 or SP7, respectively) for particle count on their surfaces.

[0459] It was found that a wafer treated with cleaning composition CCI1 in the present experiment showed a particularly low particle count on its surface after treatment.

Example 9: Measurement of Etch Loss on Aluminium Oxide (A10) Layers as a Function of pH Values of Wetch-Etch Compositions

[0460] Similar as in Example 4 above, test wafers were obtained with 3 different types of AlO.sub.x-outer layers.

[0461] The wet-etch compositions (see Example 2 and table 2 above) were prepared and the etch rates of the wet-etch compositions were determined as explained in Example 4 above or analogously to the method as explained in Example 4 above, at a temperature of 60° C.

[0462] The etch rates of the wet-etch compositions according to the invention were determined on two different sets of wafer surfaces as explained in Example 3 or Example 4 above, or analogously to these methods: on one set of wafer surfaces carrying 3 different types of AlO.sub.x-outer layers where no plasma etch had been performed (control) and on another set of wafer surfaces carrying 3 different types of AlO.sub.x-outer layers where plasma etch had been performed. The results of this experiment are shown in table 5 below.

TABLE-US-00007 TABLE 5 Results from etch tests on different types of AlO.sub.x-outer layers as a function of pH-values of wet-etch compositions Wet-etch Compositions WEI8 WEI1 WEI16 AlO.sub.x-type/wafer surface Etch rate [Å/min] AlO.sub.x-type 1/no plasma etch 4 0.9 0.8 AlO.sub.x-type 1/plasma etch 5.6 2 0.7 AlO.sub.x-type 2/no plasma etch 2.4 0.8 0.7 AlO.sub.x-type 2/plasma etch 5.4 1.8 1.5 AlO.sub.x-type 3/no plasma etch 2.1 0.8 0.5 AlO.sub.x-type 3/plasma etch 7.1 2.7 2.2

[0463] Wet-etch compositions WEI1 and WEI8 were prepared as described above (see Examples 1 and 2). Wet-etch composition WEI16 was prepared analogously to WEI1 from a cleaning composition which was identical to CCI1, with the exception that the content of tetra ethyl ammonium hydroxide (TEAH) was lower in the cleaning composition used for preparation of wet-etch composition WEI16 and was in the range of between 0.1-0.4 mass-%, relative to the total mass of the cleaning composition. The pH of wet-etch composition WEI16 was 6.5.

[0464] From the results in table 5 above it can be seen that the wet-etch compositions according to the invention which have pH values in the range of from 6 to 9, preferably of from 6.5 to 8.0, show etch-rates on different types of layers comprising an aluminium compound (different types of AlO.sub.x-outer layers), which makes said wet-etch compositions excellently suited for a very controlled and specific etching of a layer comprising or consisting of one or more aluminium compounds.