CN102427036A - High-selectivity dry etching method for HfO2 thin film - Google Patents
High-selectivity dry etching method for HfO2 thin film Download PDFInfo
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- CN102427036A CN102427036A CN2011102064625A CN201110206462A CN102427036A CN 102427036 A CN102427036 A CN 102427036A CN 2011102064625 A CN2011102064625 A CN 2011102064625A CN 201110206462 A CN201110206462 A CN 201110206462A CN 102427036 A CN102427036 A CN 102427036A
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Abstract
The invention discloses a high-selectivity dry etching method for an HfO2 thin film, wherein the method comprises the following steps: step a: carrying out main etching on the HfO2 thin film on a substrate by using mixed gas of BCl3 and gas containing H element in an etching device; and step b: carrying out over-etching on the substrate by using the mixed gas of BCl3 gas and O2 gas in the etching device. According to the invention, through the high-selectivity dry etching method for the HfO2 thin film, the problem in the prior art that the etching terminal point design is not accurate enough caused by the relatively low selection ratio for high K material HfO2 is solved; the BCl3 gas is used to carry out dry etching on the HfO2 thin film, the etching effect is very good; and the BC13 gas has higher selection ratio for the silicon substrate, and the profile of an etching device and the etching speed ratio are easy to control, thus the accuracy of an etching terminal point is improved.
Description
Technical field
The present invention relates to a kind of lithographic method, relate in particular to a kind of high selectivity dry etching method the HfO2 film.
Background technology
Existing patent (application number: 200480014635.1; The method and system that is used for the etching high-k dielectric material) use halogen gas to combine other reducing gass that high k value material is carried out etching; But its gas of selecting for use itself has various limitation: containing fluoro plasma is main to the etching of high-k dielectric material with the bombardment splash effect; And be difficult to generate volatile products, thereby can't carry out the high selectivity etching substrate; Though chlorine can form volatile products with high-k dielectric material in theory; But because its ion energy is lower; Be not enough to destroy the Hf-O key; Therefore the selective etching for Si or SiO2 substrate is difficult to realize, especially in the case, the scheme that can cause using prior art is accurate inadequately for the setting of etching terminal.
Summary of the invention
The invention discloses a kind of high selectivity dry etching method, select the relatively lower etching terminal that causes to set accurate inadequately problem for high dielectric constant material HfO2 in order to solve in the prior art to the HfO2 film.
Above-mentioned purpose of the present invention realizes through following technical scheme:
A kind of high selectivity dry etching method to the HfO2 film wherein, may further comprise the steps:
Step a: in an etching equipment, the HfO2 film on the substrate is carried out the main body etching through BCl3 gas and the mist that contains the gas composition of H element;
Step b: the mist through BCl3 gas and O2 gas composition in said etching apparatus carries out over etching to substrate.
Aforesaid high selectivity dry etching method to the HfO2 film, wherein, said etching apparatus is selected CCP, TCP, ICP, RIE equipment for use.
Aforesaid high selectivity dry etching method to the HfO2 film wherein, in the process of carrying out step a and step b etching, is controlled at etching temperature between 150 ° of C ~ 300 ° C.
Aforesaid high selectivity dry etching method to the HfO2 film, wherein, in step a, BCl3 gas and HfO2 Thin Film generate stable volatilizable product (BOCl) 3.
Aforesaid high selectivity dry etching method to the HfO2 film wherein, selects for use Si or SiO2 as substrate.
Aforesaid high selectivity dry etching method to the HfO2 film, wherein, in step b, the reaction of BCl3 gas and substrate generates and contains the B layer, makes the upper surface passivation of substrate pads.
Aforesaid high selectivity dry etching method to the HfO2 film, wherein, the H gas that contains among the step a is CxHy.
Aforesaid high selectivity dry etching method to the HfO2 film wherein, is regulated the ratio of the shared mist of BCl3 gas and O2 gas etching selection ratio and etching pattern is adjusted in step b.
In sum; Owing to adopted technique scheme; The present invention has solved in the prior art for the relatively lower accurate inadequately problem of etching terminal setting that causes of high dielectric constant material HfO2 selection the high selectivity dry etching method of HfO2 film; Adopt BCl3 gas that the HfO2 film is carried out dry etching, have good etching effect, and BCl3 gas has higher selection ratio to silicon substrate; Be easy to the pattern and the etch rate of etched features are controlled, to improve the accuracy of etching terminal.
Description of drawings
Through reading the detailed description of non-limiting example being done with reference to following accompanying drawing, it is more obvious that the present invention and characteristic thereof, profile and advantage will become.Mark identical in whole accompanying drawings is indicated identical part.Painstakingly proportionally do not draw accompanying drawing, focus on illustrating purport of the present invention.
To be the present invention be applied to the structural representation behind the first grid technology to the high selectivity dry etching method of HfO2 film to Fig. 1;
To be the present invention be applied to the flow chart in the metal gates scheme behind the first high dielectric constant layer to the high selectivity dry etching method of HfO2 film to Fig. 2.
Embodiment
Be further described below in conjunction with the accompanying drawing specific embodiments of the invention:
A kind of high selectivity dry etching method to the HfO2 film, wherein,
Step a: in an etching equipment, through BCl3 gas and the mist that contains the gas composition of H element the HfO2 film on the substrate is carried out the main body etching, wherein, BCl3 gas and HfO2 Thin Film generate volatile byproducts.
Further, BCl3 gas and HfO2 Thin Film generate stable volatilizable product (BOCl) 3, realize the dry etching to the high selectivity of high k value material HfO2 film through using the BCl3 plasma.
Etching apparatus described in the present invention can be selected CCP, TCP, ICP or RIE equipment for use, in the said equipment, carries out dry etching through the gas that is mixed with BCl3 plasma font.
In the process of carrying out step a and step b etching, can etching temperature be controlled between 150 ° of C ~ 300 ° C, that is to say that etching temperature need be not less than 150 ° of C, the highlyest can reach 300 ° of C.
The H gas that contains among the step a is CxHy, can select CH4, C2H4 etc., through regulating the BCl3 gas in the mist and containing the shared ratio of H gas, with the selection ratio of adjustment to HfO2, and then realizes the speed of etching and the control of pattern.
Step b: the mist through BCl3 gas and O2 gas composition in said etching apparatus carries out over etching to substrate, and wherein, the present invention can select for use Si or SiO2 as substrate, and BCl3 gas has higher selectivity to Si or the SiO2 as substrate.
Wherein, the reaction of BCl3 gas and substrate generates and contains the B layer, makes the upper surface passivation of substrate pads, thereby makes mist slow down to the etch rate of Si and SiO2, thereby has higher selectivity.
In step b, regulating the ratio of the shared mist of BCl3 gas and O2 gas adjusts etching selection ratio and etching pattern.
To be the present invention be applied to the structural representation behind the first grid technology to the high selectivity dry etching method of HfO2 film to Fig. 1; The disclosed dry etching method of the present invention can be used for first grid technology; Structure chart after the application sees also Fig. 1; This application can be used as the first embodiment of the present invention, and deposit one SiO2 layer, a HfO2 layer, a work function layer (Work function layer), a metal gates (Metal gate) layer, a polysilicon layer successively on a Si substrate are different from the lithographic method of available technology adopting Cl2 or F base gas; The present invention adopts that the gas of BCl3 is auxiliary to carry out dry etching with O2 or the gas that contains the H element and remove HfO2, SiO2 and Si layer; To reach better etching effect, all the other processing steps are all identical with prior art, so do not repeat them here.
The disclosed method of the present invention can also be used for metal gates scheme behind the first high dielectric constant layer; To be the present invention be applied to the flow chart in the metal gates scheme behind the first high dielectric constant layer to the high selectivity dry etching method of HfO2 film to Fig. 2; Its concrete technological process can be referring to Fig. 2; This application can be used as second embodiment of the present invention, may further comprise the steps: step 1: on silicon chip, carry out the silica membrane deposition; Step 2: carry out the HfO2 thin film deposition; Step 3: the deposition of carrying out polysilicon (Poly Silicon) film; Step 4: photoetching forms figure; Step 5: the gas through BCl3 is auxiliary to carry out dry etching with O2 or the gas that contains the H element to polysilicon film, HfO2 film and SiO2 film; Step 6: form the S/D zone, form Spacer simultaneously; Step 7: carry out inter-level dielectric (Inter layer dielectric is called for short ILD) accumulation, step 8: remove polysilicon film; Step 9: carry out the Al thin film deposition; Step 10: carry out cmp (CMP) and form metal gates (Metal gate).
Further, the disclosed dry etching method of the present invention also can be not limited in two above-mentioned embodiment suitably in the different components different process HfO2 film being carried out etching under the situation, does not repeat them here.
In sum; Owing to adopted technique scheme; The present invention has solved in the prior art for the relatively lower accurate inadequately problem of etching terminal setting that causes of high dielectric constant material HfO2 selection the high selectivity dry etching method of HfO2 film; Adopt BCl3 gas that the HfO2 film is carried out dry etching, have good etching effect, and BCl3 gas has higher selection ratio to silicon substrate; Be easy to the pattern and the etch rate of etched features are controlled, to improve the accuracy of etching terminal.
It should be appreciated by those skilled in the art that those skilled in the art combine prior art and the foregoing description can realize said variant, do not repeat them here.Such variant does not influence flesh and blood of the present invention, does not repeat them here.
More than preferred embodiment of the present invention is described.It will be appreciated that the present invention is not limited to above-mentioned specific implementations, equipment of wherein not describing in detail to the greatest extent and structure are construed as with the common mode in this area to be implemented; Any those of ordinary skill in the art; Do not breaking away under the technical scheme scope situation of the present invention; All the method for above-mentioned announcement capable of using and technology contents are made many possible changes and modification to technical scheme of the present invention; Or being revised as the equivalent embodiment of equivalent variations, this does not influence flesh and blood of the present invention.Therefore, every content that does not break away from technical scheme of the present invention, all still belongs in the scope of technical scheme protection of the present invention any simple modification, equivalent variations and modification that above embodiment did according to technical spirit of the present invention.
Claims (8)
1. the high selectivity dry etching method to the HfO2 film is characterized in that,
Step a: in an etching equipment, the HfO2 film on the substrate is carried out the main body etching through BCl3 gas and the mist that contains the gas composition of H element;
Step b: the mist through BCl3 gas and O2 gas composition in said etching apparatus carries out over etching to substrate.
2. the high selectivity dry etching method to the HfO2 film according to claim 1 is characterized in that said etching apparatus is selected CCP, TCP, ICP, RIE equipment for use.
3. the high selectivity dry etching method to the HfO2 film according to claim 1 is characterized in that, in the process of carrying out step a and step b etching, etching temperature is controlled between 150 ° of C ~ 300 ° C.
4. the high selectivity dry etching method to the HfO2 film according to claim 1 is characterized in that, in step a, BCl3 gas and HfO2 Thin Film generate stable volatilizable product (BOCl) 3.
5. the high selectivity dry etching method to the HfO2 film according to claim 1 is characterized in that, selects for use Si or SiO2 as substrate.
6. the high selectivity dry etching method to the HfO2 film according to claim 1 is characterized in that, in step b, the reaction of BCl3 gas and substrate generates and contains the B layer, makes the upper surface passivation of substrate pads.
7. the high selectivity dry etching method to the HfO2 film according to claim 1 is characterized in that, the H gas that contains among the step a is CxHy.
8. the high selectivity dry etching method to the HfO2 film according to claim 1 is characterized in that, in step b, regulates the ratio of the shared mist of BCl3 gas and O2 gas etching selection ratio and etching pattern are adjusted.
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| CN2011102064625A CN102427036A (en) | 2011-07-22 | 2011-07-22 | High-selectivity dry etching method for HfO2 thin film |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070042601A1 (en) * | 2005-08-22 | 2007-02-22 | Applied Materials, Inc. | Method for etching high dielectric constant materials |
| CN101511969A (en) * | 2006-09-12 | 2009-08-19 | 东京毅力科创株式会社 | Method and system for dry etching a hafnium containing material |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070042601A1 (en) * | 2005-08-22 | 2007-02-22 | Applied Materials, Inc. | Method for etching high dielectric constant materials |
| CN101511969A (en) * | 2006-09-12 | 2009-08-19 | 东京毅力科创株式会社 | Method and system for dry etching a hafnium containing material |
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Application publication date: 20120425 |