Summary of the invention
The present invention is directed to the HfSiON high-K gate dielectric material selectivity removal technology that how to realize high selectivity has become the present situation that realizes one of high K/ metal gate prerequisite in integrated, a kind of etching reagent of HfSiON high-K gate dielectric material is provided and uses the caustic solution of this etching reagent.
The technical scheme that the present invention solves the problems of the technologies described above is as follows: a kind of etching reagent of HfSiON high-K gate dielectric material comprises 0.19%~4.83% hydrofluoric acid by its weight percent meter.
Described etching reagent comprises 0.23%~4.06% hydrofluoric acid and 95.94%~99.77% water by its weight percent meter.
Further, described etching reagent comprises 0.19%~4.24% hydrofluoric acid, 4.32%~54.57% mineral acid and 41.19%~95.49% water by its weight percent meter.
Further, described mineral acid comprises one or more in hydrochloric acid, sulfuric acid and the phosphoric acid.
Further, described etching reagent comprises 0.22%~4.83% hydrofluoric acid, 5.31%~58.14% mineral acid and 37.03%~94.47% organic solvent by its weight percent meter.
Further, described mineral acid comprises one or more in hydrochloric acid, sulfuric acid and the phosphoric acid, and described organic solvent comprises one or both in dehydrated alcohol and the Virahol.
The present invention also provides a kind of technical scheme as follows for solving the problems of the technologies described above: a kind of caustic solution of HfSiON high-K gate dielectric material comprises HfSiON high-K gate dielectric material is formed at Si substrate, Si/SiO
2After on interfacial layer or the Si/SiON interfacial layer, it is immersed in carries out wet etching in the above-mentioned etching reagent.
Further, described caustic solution specifically comprises HfSiON high-K gate dielectric material is formed at Si substrate, Si/SiO
2After on interfacial layer or the Si/SiON interfacial layer, using plasma is handled the HfSiON high-K gate dielectric material on it, it is immersed in carries out wet etching in the above-mentioned etching reagent again.
Further, the gas that produces described plasma body is N
2Perhaps Ar.
Further, the power that described using plasma is handled is 100 watts~250 watts, and pressure is 100 millitorrs~300 millitorrs, and gas flow is 50 mark condition milliliter per minutes~200 mark condition milliliter per minutes.
The invention has the beneficial effects as follows:
1, use the etching reagent of HfSiON high-K gate dielectric material of the present invention, can reduce the hydrolysis of hydrofluoric acid, the corrosion speed that improves HfSiON high-K gate dielectric material also reduces field oxygen district SiO
2Corrosion speed, thereby improve HfSiON to field oxygen district SiO
2The selection ratio, can be simply and realize the selective removal of HfSiON high-K gate dielectric material effectively.
2, after volume ratio between each component is optimized in the etching reagent of HfSiON high-K gate dielectric material of the present invention, can realize field oxygen district SiO
2The selection ratio that material is high, thus satisfy the integrated needs of circuit.For example, the employing volume ratio is 1: 100 HF/H
2O solution, volume ratio are 1: 10: 90 HF/HCl/H
2O solution and volume ratio are 1: 10: 90 HF/HCl/ ethanol solution when carrying out HfSiON high-K gate dielectric material corrosion, and HfSiON is to field oxygen district SiO
2The selection ratio can reach 3.4: 1 respectively, 5.33: 1,21: 1.
3, after using plasma is handled HfSiON high-K gate dielectric material, by introducing damage or form the Hf N key that more is soluble in rare HF, can further improve the solution that contains HF erosion rate to HfSiON high-K gate dielectric material.
Therefore, the etching reagent of HfSiON high-K gate dielectric material of the present invention and use the caustic solution of this etching reagent not only to can be implemented in after dry etching forms gate figure in the high K/ metal gate grid structure high selectivity ground selective removal HfSiON high-K gate dielectric material; Can also be in the integrated process of two high K bimetal gates, realize the selective removal of high-K gate dielectric material, this is because two high K bimetal gates when integrated, behind the general employing wet method selective removal the first layer metal gate, the high-K gate dielectric material that also needs selective removal to expose, therefore be more suitable for the integrated of high dielectric constant/bimetal gate in the nano-scale CMOS device, the inherence that more meets super large-scale integration requires and developing direction.
Embodiment
Below in conjunction with accompanying drawing principle of the present invention and feature are described, institute gives an actual example and only is used to explain the present invention, is not to be used to limit scope of the present invention.
For loss that reduces the place zone of oxidation and the controllability that improves thin high-K gate dielectric material corrosion, generally adopt the etchant solution of rare HF as the high K of Hf base.There is following running balance in rare HF solution:
HF<=>H
++F-
HF+F-<=>HF
2-
2HF<=>H
2F
2
Because the corrosion of Hf base high-K gate dielectric is mainly by the HF in the HF solution, H
2F
2Realize Deng neutral compound, and SiO
2The HF that then mainly comes out of corrosion by ionization in the HF solution
2 -, F
-Realize Deng negatively charged ion.Can improve H in the solution so in rare HF solution, add strong acid such as HCl
+Concentration, the running balance that makes rare HF exist moves to left, and reduces the decomposition of HF, improves HF, H
2F
2Concentration, reduce HF
2 -, F
-Concentration, and then improve the erosion rate of high-K gate dielectric material, reduce SiO
2Erosion rate, thereby improve Hf base high-K gate dielectric material to SiO
2The selection ratio.In like manner, adopt organic solvent replacement water such as dehydrated alcohol, also can reduce the hydrolysis of HF, improve Hf base high-K gate dielectric material SiO
2The selection ratio.So,, must adopt the solution that contains HF to carry out wet etching in order to realize the selective removal of HfSiON high-K gate dielectric material.This solution can be the mixing solutions of HF and water, also can be the mixing solutions of HF, other mineral acids and water, also can be the mixing solutions of HF, other mineral acids and organic solvent.
Embodiment 1
In present embodiment 1, the etching reagent of described HfSiON high-K gate dielectric material comprises 0.23%~4.06% hydrofluoric acid and 95.94%~99.77% water by its weight percent meter.In the present embodiment, the concentration of described hydrofluoric acid is 40%, and density is 1.13g/cm
3
Embodiment 2
In present embodiment 2, the etching reagent of described HfSiON high-K gate dielectric material comprises 0.19%~4.24% hydrofluoric acid, 4.32%~54.57% mineral acid and 41.19%~95.49% water by its weight percent meter.Described mineral acid comprises one or more in hydrochloric acid, sulfuric acid and the phosphoric acid, and preferably, described mineral acid is a hydrochloric acid.In the present embodiment, the concentration of described hydrofluoric acid is 40%, and density is 1.13g/cm
3The concentration of described hydrochloric acid is 37.5%, and relative density is 1.18g/cm
3Described vitriolic concentration is 96%, and relative density is 1.84g/cm
3Described concentration of phosphoric acid is 85%, and relative density is 1.84g/cm
3
When described mineral acid was hydrochloric acid, described etching reagent comprised 0.22%~4.24% hydrofluoric acid, 4.32%~12.44% hydrochloric acid and 83.32%~95.46% water by its weight percent meter.When described mineral acid was sulfuric acid, described etching reagent comprised 0.2%~3.35% hydrofluoric acid, 23.41%~52.38% sulfuric acid and 44.27%~76.39% water by its weight percent meter.When described mineral acid was phosphoric acid, described etching reagent comprised 0.19%~3.15% hydrofluoric acid, 26.65%~54.57% phosphoric acid and 42.28%~73.16% water by its weight percent meter.
Embodiment 3
In present embodiment 3, the etching reagent of described HfSiON high-K gate dielectric material comprises 0.22%~4.83% hydrofluoric acid, 5.31%~58.14% mineral acid and 37.03%~94.47% organic solvent by its weight percent meter.Described mineral acid comprises one or more in hydrochloric acid, sulfuric acid and the phosphoric acid, and preferably, described mineral acid is a hydrochloric acid.Described organic solvent comprises one or both in dehydrated alcohol and the Virahol, and preferably, described organic solvent is a dehydrated alcohol.In the present embodiment, the concentration of described hydrofluoric acid is 40%, and density is 1.13g/cm
3The concentration of described hydrochloric acid is 37.5%, and relative density is 1.18g/cm
3Described vitriolic concentration is 96%, and relative density is 1.84g/cm
3Described concentration of phosphoric acid is 85%, and relative density is 1.84g/cm
3
When described mineral acid is a hydrochloric acid, described organic solvent be dehydrated alcohol the time, described etching reagent comprises 0.27%~4.81% hydrofluoric acid, 5.31%~45.11% hydrochloric acid and 50.35%~93.5% dehydrated alcohol by its weight percent meter.When described mineral acid is a sulfuric acid, described organic solvent be dehydrated alcohol the time, described etching reagent comprises 0.24%~3.63% hydrofluoric acid, 27.82%~56.81% sulfuric acid and 41.67%~70.29% dehydrated alcohol by its weight percent meter.When described mineral acid is a phosphoric acid, described organic solvent be dehydrated alcohol the time, described etching reagent comprises 0.22%~3.35% hydrofluoric acid, 28.12%~57.98% phosphoric acid and 39.67%~69.52% dehydrated alcohol by its weight percent meter.When described mineral acid is a hydrochloric acid, described organic solvent is and during Virahol, and described etching reagent comprises 0.27%~4.83% hydrofluoric acid, 5.36%~57.20% hydrochloric acid and 39.56%~91.17% Virahol by its weight percent meter.When described mineral acid is a sulfuric acid, when described organic solvent was Virahol, described etching reagent comprised 0.24%~4.65% hydrofluoric acid, 6.18%~57.03% sulfuric acid and 38.90%~93.48% Virahol by its weight percent meter.When described mineral acid is a phosphoric acid, when described organic solvent was Virahol, described etching reagent calculated by its weight percent and comprises 0.23%~4.36% hydrofluoric acid, 9.35%~58.14% phosphoric acid and 40%~89.92% Virahol.
Embodiment 4
In present embodiment 4, the caustic solution of described HfSiON high-K gate dielectric material comprises HfSiON high-K gate dielectric material is formed at Si substrate, Si/SiO
2After on interfacial layer or the Si/SiON interfacial layer, it is immersed in embodiment 1 to 3 arbitrary described etching reagent carries out wet etching.
Embodiment 5
In present embodiment 5, the caustic solution of described HfSiON high-K gate dielectric material comprises HfSiON high-K gate dielectric material is formed at Si substrate, Si/SiO
2After on interfacial layer or the Si/SiON interfacial layer, the HfSiON high-K gate dielectric material on it is carried out Cement Composite Treated by Plasma, again it is immersed in embodiment 1 to 3 arbitrary described etching reagent and carries out wet etching.By plasma body the high-K gate dielectric material surface is handled, caused the physical damnification or the chemical reaction of high-K gate dielectric material surface, thereby increase the erosion rate of wet etching.The gas that using plasma is handled HfSiON high-K gate dielectric material is N
2Or Ar, the Ar plasma body can cause physical damnification to the high-K gate dielectric material surface, thereby improves wet etching speed; Nitrogen plasma not only can cause physical damnification to the high-K gate dielectric material surface, can also form the Hf-N key that more is soluble in HF with the reaction of high-K gate dielectric material, thereby improve wet etching speed.The power that using plasma is handled the HfSiON hafnium is 100 watts of (W)~250W, and pressure is 100 millitorrs (mt)~300mt, and gas flow is 50 mark condition milliliter per minute (sccm)~200sccm.
Embodiment 6
HfSiON dielectric thickness change curve when Fig. 1 adopts the method for embodiment 4 that HfSiON high-K gate dielectric material is corroded for the embodiment of the invention 6.As shown in Figure 1, for Si/SiO through 900 ℃ of high temperature rapid thermal annealings
2(1nm)/and HfSiON (7.4nm) structure, the employing volume ratio is 1: 100 HF/H
2O solution corrodes, and its etching time and residue HfSiON dielectric thickness change curve are as shown in Figure 1.Wherein, the HfSiON dielectric thickness is to obtain by spectroscopic ellipsometer measured curve and theoretical model match.
Embodiment 7
Fig. 2 is the x-ray photoelectron energy spectrogram after the embodiment of the invention 7 adopts the method for embodiment 5 that HfSiON high-K gate dielectric material is corroded.As shown in Figure 2, for Si/SiO
2/ HfSiON structure behind 900 ℃ of high temperature rapid thermal annealings, is 120W in source power, and pressure is 200mt, N
2Gas flow is under the condition of 100sccm, adopts N
2Behind the Cement Composite Treated by Plasma 10S, in volume ratio 1: 10: 89 HF/HCl/H
2Corrosion was adopted x-ray photoelectron power spectrum (XPS) analytical results as shown in Figure 2 after 20 seconds in the O solution.As can be seen from Figure 2, behind Cement Composite Treated by Plasma and the wet etching, the peak value of Hf4f has disappeared, and proves that the surface has not had the Hf element, and promptly the HfSiON medium is removed fully.
The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.