CA1208810A - Method of manufacturing a semiconductor device by means of plasma etching - Google Patents
Method of manufacturing a semiconductor device by means of plasma etchingInfo
- Publication number
- CA1208810A CA1208810A CA000440705A CA440705A CA1208810A CA 1208810 A CA1208810 A CA 1208810A CA 000440705 A CA000440705 A CA 000440705A CA 440705 A CA440705 A CA 440705A CA 1208810 A CA1208810 A CA 1208810A
- Authority
- CA
- Canada
- Prior art keywords
- fluorine
- gas
- reactor
- silicon nitride
- gas mixture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 7
- 239000004065 semiconductor Substances 0.000 title claims abstract description 7
- 238000001020 plasma etching Methods 0.000 title abstract 2
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 28
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 23
- 239000011737 fluorine Substances 0.000 claims abstract description 23
- 229910052736 halogen Inorganic materials 0.000 claims abstract description 19
- 150000002367 halogens Chemical class 0.000 claims abstract description 19
- 239000000203 mixture Substances 0.000 claims abstract description 17
- 239000000758 substrate Substances 0.000 claims abstract description 10
- 150000001875 compounds Chemical class 0.000 claims abstract description 7
- 239000000470 constituent Substances 0.000 claims abstract description 7
- 150000002222 fluorine compounds Chemical class 0.000 claims abstract description 4
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims abstract 7
- 239000007789 gas Substances 0.000 claims description 42
- 238000000034 method Methods 0.000 claims description 15
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 claims description 9
- 229910052794 bromium Inorganic materials 0.000 claims description 8
- RJCQBQGAPKAMLL-UHFFFAOYSA-N bromotrifluoromethane Chemical compound FC(F)(F)Br RJCQBQGAPKAMLL-UHFFFAOYSA-N 0.000 claims description 7
- -1 bromine compound Chemical class 0.000 claims description 5
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 claims description 3
- 239000001307 helium Substances 0.000 claims description 3
- 229910052734 helium Inorganic materials 0.000 claims description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 3
- 238000005530 etching Methods 0.000 abstract description 28
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 24
- 229910052814 silicon oxide Inorganic materials 0.000 abstract description 21
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 16
- 210000002381 plasma Anatomy 0.000 description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 150000002926 oxygen Chemical class 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 150000002366 halogen compounds Chemical class 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical compound FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000000059 patterning Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- ABTOQLMXBSRXSM-UHFFFAOYSA-N silicon tetrafluoride Chemical group F[Si](F)(F)F ABTOQLMXBSRXSM-UHFFFAOYSA-N 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 235000012431 wafers Nutrition 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31105—Etching inorganic layers
- H01L21/31111—Etching inorganic layers by chemical means
- H01L21/31116—Etching inorganic layers by chemical means by dry-etching
Abstract
ABSTRACT:
"Method of manufacturing a semiconductor device by means of plasma etching."
A method of manufacturing a semiconductor device, in which a layer of silicon nitride (3) overlying a silicon oxide layer (4) present on a substrate (2) is etched by bring-ing it into contact with substantially only uncharged con-stituents of a plasma formed in a reactor to which a sub-sgantially oxygen-free gas or gas mixture is supplied.
According to the invention, 0.1 to 25% by volume of a halogen different from fluorine or of a compound containing a halogen different from fluorine are added to this gas or gas mixture which contains fluorine or a fluorine compound.
Thus, a high etching selectivity of silicon nitride with respect to silicon oxide is obtained, which moreover, does not vary during etching.
"Method of manufacturing a semiconductor device by means of plasma etching."
A method of manufacturing a semiconductor device, in which a layer of silicon nitride (3) overlying a silicon oxide layer (4) present on a substrate (2) is etched by bring-ing it into contact with substantially only uncharged con-stituents of a plasma formed in a reactor to which a sub-sgantially oxygen-free gas or gas mixture is supplied.
According to the invention, 0.1 to 25% by volume of a halogen different from fluorine or of a compound containing a halogen different from fluorine are added to this gas or gas mixture which contains fluorine or a fluorine compound.
Thus, a high etching selectivity of silicon nitride with respect to silicon oxide is obtained, which moreover, does not vary during etching.
Description
lZ~t38~0 PHN. 10.498 The invention relates to a method of manufacturing a semiconductor de~ice, in which.a layer of silicon nitride present on a substrate is etched by bringing the layer into contact with substantially only uncharged constituents of a plasma which is formed in a reactor to which a substantially oxygen-free gas or gas mixture is supplied which comprises fluorine or a fluorine compound.
Such:a method is particularly suitable for pattern-ing a silicon nitride layer present on a silicon oxide layer by etching. The silicon nitride pattern thus obtained can be used as an oxidation.mask or:as.an implantation mask. Damage of the silicon oxide layer then exposed during etching is avoided because substantially only uncharged constituents of the plasma are utilized,:as is the case, for example, in con-ventional tunnel reactors Canadian Patent No. 1,117,400 issued February 2,1982.to Scornav:ac~a et al di.scloses a method of the kind men-tioned in the preamble, in which the gas supplied to the reactor is silicon tetrafluoride~ Silicon nitride is etched rapidly.by the constituents of.the plasma formed in this sub-stantially oxygen-free gas, whereas silicon oxide is not .attacked.
A disadvan.tage o.the known described method is that.in practice.the high etching selectivity mentioned:above - the ratio:between the speeds:at which silicon nitride and silicon oxide are etch.ed - is not.reached and that moreover .the degree of.this selectiYity may.vary during etching.
'~he in~entio~ has l~ .alia for its object to provide:a method which renders it possible to etch silicon nitride layers with.a high selectivity with respect to sili-con oxide layers, the etching selectivity substantially not .~arying during etching~ ~ccording-to the invention, the method mentioned in the pr~amble is therefore characterized in that 0.1 to 25~ by.Yolume of.a halogen different from fluorine or of:a ~aseoUs c.ompound containing a halogen `t .
12(~810 PHN. 10.498 2 different from fluorine is added to the gas or gas mixture supplied to the reactor.
The invention is:based on the recognition of the fact that in practice the plasma.always contains~a small quantity of oxygen, by which the etching selectivity of silicon nitride with respect to silicon oxide is strongly influenced. As is:also.apparent from the said Canadian Patent, this selectivity rapidly decreases when only a few per cent by volume of oxygen are.added to the gas in which the plasma is:formed~ Through small leaks, air can pene-trate into the reactor operated:at:a sub-atmospheric pressure. Furthermore, reactor parts can evolve oxygen during operation~
The oxygen, which is un.intentionally present in the reactor, is converted in.the plasma into:activated oxygen, as~a result of which silicon nitride is converted.at least in part into silicon oxide. This conversion proceeds during etching. It is~also probable that:activated oxygen gives.rise to higher speeds of etching silicon oxide. This may resuIt in:that.the e~ching selectivity of silicon nitride with respect to silicon oxide is comparatively low.and de-creases during etchin.g. It is presumed, however, that in.a method:according to.the in~ention the:activated atomic oxygen, before.reaching.the subs~rate, reacts with the halogen differ-ent from fluorine present in the plasma and is then convertedinto considerably less;active molecular oxygen. As.a result, .the said disadvantageous effects wouId.be suppressed,.as in practice has proved.to be.the case.
The method according to.the invention is preferably characterized in that.bromine or.a.bromine compound is.added to.the gas or gas mixture supplied.to.the reactor.
Due.to this addition,;a high etching selectiv.ity of silicon nitride with respect.to silicon oxide is obtained ~hich does not very substantially during etching.
Silicon nitride is etched only.very selectively with respect.to silicon o~ide but:~also very rapidly if the ~as or ` -lZ~8810 PHN.10.49S 3 4 7.1983 gas mixture supplied to the reactor comprises NF3.
The invention will now be described more fully by way of example with reference to the drawings and with re-ference to a few examples. In the drawings:
Figures 1 and 2 show di~erent stages of the manufacture o~ a semiconductor device by means of the method according to the invention, Fig. 3 shows diagrammatically a device for carrying out the method according to the invention, and Figures 4 and 5 represent speedsat which the silicon nitride and silicon oxide layers are etched and the selectivi-ties with which these layers are etched with respect to each other, respectively, as a function of the quantity of the gaseous compound which contains a halogen different from 15 fluorine and which is added to a fluorine cont~;n;ng gas supplied to the reactor.
Figures 1 and 2 show different stages o~ the manu-facture of a semiconductor device by means of a method in which a layer of silicon nitride 3 present on a substrate 2 20 is etched. The silicon nitride layer 3 is separated in this embodiment from the substrate 2 by a layer of silicon oxide 4. In a conventional manner, a mask 5 of, for example, photolacquer is provided on the silicon nitride layer 3, after which the then uncovered part of the silicon nitride 25 layer 3 is etched away. The silicon nitride pattern thus obtained can then be used as an oxidation mask or as an implantation mask.
The silicon nitride layer 3 is etched by bringing it into contact with substantially only uncharged constituents 30 of a plasma which is formed in the reactor 10 shown in Fig.3.
The reactor 10 comprises a reactor vessel 11 of quartz glass within which is arranged an aluminium tunnel 12. In the reactor 10, a plasma is produced in the space 15 located between the reactor vessel 11 and the tunnel 12 by means of 35 an electrode system 13 and a high-frequency transmitter 14.
The tunnel 12 is provided with openings 16 through which sub-stantially only uncharged constituents of the plasma can penetrate into the space 17 within the tunnel 12. In the ~ 8 1~
PHN.10.49~ 4.7.1983 space 17, a number of substrates 1 are arranged on a holder 1~.
A substsntially oxygen-free gas or gas mixture con-t~;~;ng fluorine or a fluorine compound is supplied to the reactor 10 from a container 19. According to the invention, 0.1 to 25% by volume of a halogen different from fluorine or of a gaseous compound cont~;n;ng a halogen different from fluorine is added thereto from a container 20. By means of a pump 21, the space within the reactor 10 is kept at a lO low pressure.
By means of the method according to the invention, as will appear from the following examples, silicon nitride can be etched with a high selectivity with respect to sili-con oxide, the etching selectivity not varying substantially 5 during etching. It is presumed that activated oxygen which is formed in the plasma from oxygen which may have penetrated through leaks and is evolved by reactor parts before reach-ing the substrates 1, reacts with the added halogen and is converted into less active molecular oxygen. The said etch-20 ing selectivity would be adversely affected by activatedoxygen.
Preferably, bromine or a bromine compound is added to the gas or gas mixture supplied to the reactor. As will appear from the following examples, a high etching selectivi 25 ty of silicon nitride with respect to silicon oxide can be obtained, which does not vary substantially during etching.
A particularly suitable bromine compound is CF3~r.
In the examples to be described hereinafter, silicon wafers 2 having a diameter of approximately 75 mm 30 and coated with a silicon oxide layer 4 which is approximate-ly 20 nm thickness and with an approximately 125 nm thick were etched in a plasma produced in a reactor of the type described hereinbefore. The plasma was produced with the aid of a high-frequency field at a frequency of 13.56 ~Hz.
Example 1-Fig. 4 represents speeds R at which silicon nitrideand silicon oxide are etched and Fig. 5 shows the ratio of 2a~slu PI-~.10.~9S 5 4.7.1983 these speeds (the etching selectivity S) as a function of the quantity of a gaseous compound which contains a halogen di~ferent fr~m fluorine and which is added to the gas supplied to the reactor. In this example, the said ~aseous compound is CF3Br or CF2~l2. This compound is added to a mixture of heli~l and fluorine which contains fluorine in a quantity of approximately 5% by volume. The gas stream invariably amounted to approximately 200 scc/min, and the high-frequen-cy power supplied was approximately 1 50W. The temperature lO of the substrates was approximately 10~C and the pressure in the reactor vessel was approximately 200 PA.
By addition of CF3Br or CF2Cl2, it is achieved that the etching selectivity increases. It further appears from the following Table that this selectivity does not l5 vary during etching; this in contrast with the case in which no additional halogen is added.
TABLE
; Selectivity Si3N4/SiO2 ____________ _ ___ ~ _ __I
20! ! 1% by vol.CF3Br ! 1, 5% by vol.CF2Cl2j no addition!
! T--!after 1 min; 19 ! 9~5 ; 4 ~after 3 min. 19 ~ 9~5 j 3 !after 7 min; 19 ! 9~5 ! 3 ! ! ! ! !
_______________________________________________________ _ It app~ars that a particularly favourable etching selectivity which does not vary during etching is obtained if the gas mixture supplied to the reactor consists of helium and 2 to 10% by volume of fluorine, to which 0.5 to 2% by volume of CF3Br are added.
Instead of helium, other rare gases or nitrogen may be used, although in these cases plasmas are produced which are slightly less uniform.
Example 2:
__________ In this example, the gas or gas miæture supplied to the reactor comprises N~3. The gas stream in this example amounted to 5 scc/min, the pressure was approximate-ly (25 Pa), the electrical power supplied was 100 W and the lZ(~88~
P~.10.49~ 6 4.7.1983 substrate temperature was approximately 100 C. Without addition of additional halogen, -the etching selectivity of silicon nitride with respect to silicon oxide was approxi-mately 8. When 50,b by volume of CF2CL2 was added to the gas supplied to the reactor, this selectivity became approximate-ly 10, while it became approximately 12 by the addition of 10% by volume of CF3Br. The use of NF3 has the particular advantage that silicon nitride can be etched rapidly, under the given etching conditions~ this etching speed was approxi-10 mately 80 nm/min. By the addition of other gases - rare gases~
nitrogen~ slowly etching gases, such as CF4 -~ this speed can be reduced, if desired for practical uses, whilst main-t~;n;ng the high etching selectivity.
Example 3.
In this example, the gas or gas mixture supplied to the reactor consisted of CF4, -to which 5% by volume of Br2 were added as a halogen different from fluorine. The gas stream was in this example 200 scc/min, the pressure was (67 Pa) and the electrical power supplied was 500 Watts.
20 Under these conditions, silicon nitride was etched at a speed of approximately 20 nm/min. The e-tching slectivity with respect to silicon oxide was higher than 100, whereas this selectivity was approximately 5 without the addition of the additional halogen.
Example 4:
_ _ _ _ In this example, the gas or gas mixture supplied to the reactor consisted of SE6. As the additional halogen compound~ 5% by volume of CE3Br were added thereto. The 30 gas stream was 100 scc/min, the pressure was (67 Pa), the electrical power supplied was 200 Watts and the substrate temperature was 125C. Silicon nitride was etched under these conditions a-t a speed of 5 nm/min. The etching select-ivity with respect to silicon oxide was higher than 10, 35 whereas this selectivity was approximately 4 without the addition of additional halogen.
It should be appreciated that the invention is not limited to the examples given, ~u-t that modifications ~2~8810 Pl~.1Q.49S 7 4.7.1983 are possible without departing from the scope of the in-vention. For e~ample, a halogen different from fluorine or a halogen compound cont~;n;ng a halogen different from fluorine may also be added to the gas supplied to the reactor by introducing into the reactor a substance slowly evaporating at a low pressure, such as, for example, a bro-mine-cont~;n; ng polymer.
Such:a method is particularly suitable for pattern-ing a silicon nitride layer present on a silicon oxide layer by etching. The silicon nitride pattern thus obtained can be used as an oxidation.mask or:as.an implantation mask. Damage of the silicon oxide layer then exposed during etching is avoided because substantially only uncharged constituents of the plasma are utilized,:as is the case, for example, in con-ventional tunnel reactors Canadian Patent No. 1,117,400 issued February 2,1982.to Scornav:ac~a et al di.scloses a method of the kind men-tioned in the preamble, in which the gas supplied to the reactor is silicon tetrafluoride~ Silicon nitride is etched rapidly.by the constituents of.the plasma formed in this sub-stantially oxygen-free gas, whereas silicon oxide is not .attacked.
A disadvan.tage o.the known described method is that.in practice.the high etching selectivity mentioned:above - the ratio:between the speeds:at which silicon nitride and silicon oxide are etch.ed - is not.reached and that moreover .the degree of.this selectiYity may.vary during etching.
'~he in~entio~ has l~ .alia for its object to provide:a method which renders it possible to etch silicon nitride layers with.a high selectivity with respect to sili-con oxide layers, the etching selectivity substantially not .~arying during etching~ ~ccording-to the invention, the method mentioned in the pr~amble is therefore characterized in that 0.1 to 25~ by.Yolume of.a halogen different from fluorine or of:a ~aseoUs c.ompound containing a halogen `t .
12(~810 PHN. 10.498 2 different from fluorine is added to the gas or gas mixture supplied to the reactor.
The invention is:based on the recognition of the fact that in practice the plasma.always contains~a small quantity of oxygen, by which the etching selectivity of silicon nitride with respect to silicon oxide is strongly influenced. As is:also.apparent from the said Canadian Patent, this selectivity rapidly decreases when only a few per cent by volume of oxygen are.added to the gas in which the plasma is:formed~ Through small leaks, air can pene-trate into the reactor operated:at:a sub-atmospheric pressure. Furthermore, reactor parts can evolve oxygen during operation~
The oxygen, which is un.intentionally present in the reactor, is converted in.the plasma into:activated oxygen, as~a result of which silicon nitride is converted.at least in part into silicon oxide. This conversion proceeds during etching. It is~also probable that:activated oxygen gives.rise to higher speeds of etching silicon oxide. This may resuIt in:that.the e~ching selectivity of silicon nitride with respect to silicon oxide is comparatively low.and de-creases during etchin.g. It is presumed, however, that in.a method:according to.the in~ention the:activated atomic oxygen, before.reaching.the subs~rate, reacts with the halogen differ-ent from fluorine present in the plasma and is then convertedinto considerably less;active molecular oxygen. As.a result, .the said disadvantageous effects wouId.be suppressed,.as in practice has proved.to be.the case.
The method according to.the invention is preferably characterized in that.bromine or.a.bromine compound is.added to.the gas or gas mixture supplied.to.the reactor.
Due.to this addition,;a high etching selectiv.ity of silicon nitride with respect.to silicon oxide is obtained ~hich does not very substantially during etching.
Silicon nitride is etched only.very selectively with respect.to silicon o~ide but:~also very rapidly if the ~as or ` -lZ~8810 PHN.10.49S 3 4 7.1983 gas mixture supplied to the reactor comprises NF3.
The invention will now be described more fully by way of example with reference to the drawings and with re-ference to a few examples. In the drawings:
Figures 1 and 2 show di~erent stages of the manufacture o~ a semiconductor device by means of the method according to the invention, Fig. 3 shows diagrammatically a device for carrying out the method according to the invention, and Figures 4 and 5 represent speedsat which the silicon nitride and silicon oxide layers are etched and the selectivi-ties with which these layers are etched with respect to each other, respectively, as a function of the quantity of the gaseous compound which contains a halogen different from 15 fluorine and which is added to a fluorine cont~;n;ng gas supplied to the reactor.
Figures 1 and 2 show different stages o~ the manu-facture of a semiconductor device by means of a method in which a layer of silicon nitride 3 present on a substrate 2 20 is etched. The silicon nitride layer 3 is separated in this embodiment from the substrate 2 by a layer of silicon oxide 4. In a conventional manner, a mask 5 of, for example, photolacquer is provided on the silicon nitride layer 3, after which the then uncovered part of the silicon nitride 25 layer 3 is etched away. The silicon nitride pattern thus obtained can then be used as an oxidation mask or as an implantation mask.
The silicon nitride layer 3 is etched by bringing it into contact with substantially only uncharged constituents 30 of a plasma which is formed in the reactor 10 shown in Fig.3.
The reactor 10 comprises a reactor vessel 11 of quartz glass within which is arranged an aluminium tunnel 12. In the reactor 10, a plasma is produced in the space 15 located between the reactor vessel 11 and the tunnel 12 by means of 35 an electrode system 13 and a high-frequency transmitter 14.
The tunnel 12 is provided with openings 16 through which sub-stantially only uncharged constituents of the plasma can penetrate into the space 17 within the tunnel 12. In the ~ 8 1~
PHN.10.49~ 4.7.1983 space 17, a number of substrates 1 are arranged on a holder 1~.
A substsntially oxygen-free gas or gas mixture con-t~;~;ng fluorine or a fluorine compound is supplied to the reactor 10 from a container 19. According to the invention, 0.1 to 25% by volume of a halogen different from fluorine or of a gaseous compound cont~;n;ng a halogen different from fluorine is added thereto from a container 20. By means of a pump 21, the space within the reactor 10 is kept at a lO low pressure.
By means of the method according to the invention, as will appear from the following examples, silicon nitride can be etched with a high selectivity with respect to sili-con oxide, the etching selectivity not varying substantially 5 during etching. It is presumed that activated oxygen which is formed in the plasma from oxygen which may have penetrated through leaks and is evolved by reactor parts before reach-ing the substrates 1, reacts with the added halogen and is converted into less active molecular oxygen. The said etch-20 ing selectivity would be adversely affected by activatedoxygen.
Preferably, bromine or a bromine compound is added to the gas or gas mixture supplied to the reactor. As will appear from the following examples, a high etching selectivi 25 ty of silicon nitride with respect to silicon oxide can be obtained, which does not vary substantially during etching.
A particularly suitable bromine compound is CF3~r.
In the examples to be described hereinafter, silicon wafers 2 having a diameter of approximately 75 mm 30 and coated with a silicon oxide layer 4 which is approximate-ly 20 nm thickness and with an approximately 125 nm thick were etched in a plasma produced in a reactor of the type described hereinbefore. The plasma was produced with the aid of a high-frequency field at a frequency of 13.56 ~Hz.
Example 1-Fig. 4 represents speeds R at which silicon nitrideand silicon oxide are etched and Fig. 5 shows the ratio of 2a~slu PI-~.10.~9S 5 4.7.1983 these speeds (the etching selectivity S) as a function of the quantity of a gaseous compound which contains a halogen di~ferent fr~m fluorine and which is added to the gas supplied to the reactor. In this example, the said ~aseous compound is CF3Br or CF2~l2. This compound is added to a mixture of heli~l and fluorine which contains fluorine in a quantity of approximately 5% by volume. The gas stream invariably amounted to approximately 200 scc/min, and the high-frequen-cy power supplied was approximately 1 50W. The temperature lO of the substrates was approximately 10~C and the pressure in the reactor vessel was approximately 200 PA.
By addition of CF3Br or CF2Cl2, it is achieved that the etching selectivity increases. It further appears from the following Table that this selectivity does not l5 vary during etching; this in contrast with the case in which no additional halogen is added.
TABLE
; Selectivity Si3N4/SiO2 ____________ _ ___ ~ _ __I
20! ! 1% by vol.CF3Br ! 1, 5% by vol.CF2Cl2j no addition!
! T--!after 1 min; 19 ! 9~5 ; 4 ~after 3 min. 19 ~ 9~5 j 3 !after 7 min; 19 ! 9~5 ! 3 ! ! ! ! !
_______________________________________________________ _ It app~ars that a particularly favourable etching selectivity which does not vary during etching is obtained if the gas mixture supplied to the reactor consists of helium and 2 to 10% by volume of fluorine, to which 0.5 to 2% by volume of CF3Br are added.
Instead of helium, other rare gases or nitrogen may be used, although in these cases plasmas are produced which are slightly less uniform.
Example 2:
__________ In this example, the gas or gas miæture supplied to the reactor comprises N~3. The gas stream in this example amounted to 5 scc/min, the pressure was approximate-ly (25 Pa), the electrical power supplied was 100 W and the lZ(~88~
P~.10.49~ 6 4.7.1983 substrate temperature was approximately 100 C. Without addition of additional halogen, -the etching selectivity of silicon nitride with respect to silicon oxide was approxi-mately 8. When 50,b by volume of CF2CL2 was added to the gas supplied to the reactor, this selectivity became approximate-ly 10, while it became approximately 12 by the addition of 10% by volume of CF3Br. The use of NF3 has the particular advantage that silicon nitride can be etched rapidly, under the given etching conditions~ this etching speed was approxi-10 mately 80 nm/min. By the addition of other gases - rare gases~
nitrogen~ slowly etching gases, such as CF4 -~ this speed can be reduced, if desired for practical uses, whilst main-t~;n;ng the high etching selectivity.
Example 3.
In this example, the gas or gas mixture supplied to the reactor consisted of CF4, -to which 5% by volume of Br2 were added as a halogen different from fluorine. The gas stream was in this example 200 scc/min, the pressure was (67 Pa) and the electrical power supplied was 500 Watts.
20 Under these conditions, silicon nitride was etched at a speed of approximately 20 nm/min. The e-tching slectivity with respect to silicon oxide was higher than 100, whereas this selectivity was approximately 5 without the addition of the additional halogen.
Example 4:
_ _ _ _ In this example, the gas or gas mixture supplied to the reactor consisted of SE6. As the additional halogen compound~ 5% by volume of CE3Br were added thereto. The 30 gas stream was 100 scc/min, the pressure was (67 Pa), the electrical power supplied was 200 Watts and the substrate temperature was 125C. Silicon nitride was etched under these conditions a-t a speed of 5 nm/min. The etching select-ivity with respect to silicon oxide was higher than 10, 35 whereas this selectivity was approximately 4 without the addition of additional halogen.
It should be appreciated that the invention is not limited to the examples given, ~u-t that modifications ~2~8810 Pl~.1Q.49S 7 4.7.1983 are possible without departing from the scope of the in-vention. For e~ample, a halogen different from fluorine or a halogen compound cont~;n;ng a halogen different from fluorine may also be added to the gas supplied to the reactor by introducing into the reactor a substance slowly evaporating at a low pressure, such as, for example, a bro-mine-cont~;n; ng polymer.
Claims (5)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS
1. A method of manufacturing a semiconductor device, in which a layer of silicon nitride present on a substrate is etched by bringing the layer into contact with substantial-ly only uncharged constituents of a plasma formed in a react-or to which a substantially oxygen-free gas or gas mixture is supplied which comprises fluorine or a fluorine compound, characterised in that 0.1 to 25% by volume of a halogen dif-ferent from fluorine or of a gaseous compound containing a halogen different from fluorine are added to the gas or gas mixture supplied to the reactor.
2. A method as claimed in Claim 1, characterised in that bromine or a bromine compound is added to the gas or gas mixture supplied to the reactor.
3. A method as claimed in Claim 2, characterised in that the bromine compound is CF3Br.
4. A method as claimed in Claim 3, characterised in that the gas mixture supplied to the reactor consists of helium and 2 to 10% by volume of fluorine, to which 0.5 to 2% by volume of CF3Br are added.
5. A method as claimed in any of Claims 1, 2 or 3, characterised in that the gas or gas mixture supplied to the reactor comprises NF3.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8204437 | 1982-11-16 | ||
| NL8204437A NL8204437A (en) | 1982-11-16 | 1982-11-16 | METHOD FOR MANUFACTURING A SEMICONDUCTOR DEVICE USING PLASMA ETCHING |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1208810A true CA1208810A (en) | 1986-07-29 |
Family
ID=19840600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000440705A Expired CA1208810A (en) | 1982-11-16 | 1983-11-08 | Method of manufacturing a semiconductor device by means of plasma etching |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4717447A (en) |
| EP (1) | EP0109706B1 (en) |
| JP (1) | JPS59100539A (en) |
| CA (1) | CA1208810A (en) |
| DE (1) | DE3369600D1 (en) |
| NL (1) | NL8204437A (en) |
Families Citing this family (26)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61158143A (en) * | 1984-12-29 | 1986-07-17 | Fujitsu Ltd | Etching method for insulating film |
| US5180466A (en) * | 1984-12-29 | 1993-01-19 | Fujitsu Limited | Process for dry etching a silicon nitride layer |
| JPS6399533A (en) * | 1986-05-31 | 1988-04-30 | Toshiba Corp | Method and apparatus for dry etching of silicon nitride film |
| US4778583A (en) * | 1987-05-11 | 1988-10-18 | Eastman Kodak Company | Semiconductor etching process which produces oriented sloped walls |
| US4878995A (en) * | 1987-07-02 | 1989-11-07 | Kabushiki Kaisha Toshiba | Method of dry etching and apparatus for use in such method |
| US4844773A (en) * | 1987-07-16 | 1989-07-04 | Texas Instruments Incorporated | Process for etching silicon nitride film |
| KR930005440B1 (en) * | 1989-10-02 | 1993-06-21 | 다이닛뽕 스쿠린 세이소오 가부시키가이샤 | Selective removing method of insulate film |
| US5188704A (en) * | 1989-10-20 | 1993-02-23 | International Business Machines Corporation | Selective silicon nitride plasma etching |
| EP0424299A3 (en) * | 1989-10-20 | 1991-08-28 | International Business Machines Corporation | Selective silicon nitride plasma etching |
| JPH04302426A (en) * | 1991-03-29 | 1992-10-26 | Sony Corp | Digital etching method |
| DE4232475C2 (en) * | 1992-09-28 | 1998-07-02 | Siemens Ag | Process for plasma chemical dry etching of Si¶3¶N¶4¶ layers highly selective to SiO¶2¶ layers |
| US5338395A (en) * | 1993-03-10 | 1994-08-16 | Micron Semiconductor, Inc. | Method for enhancing etch uniformity useful in etching submicron nitride features |
| DE4315435C2 (en) * | 1993-05-08 | 1995-03-09 | Itt Ind Gmbh Deutsche | Method for the selective etching of insulating and buffer layers arranged on a semiconductor substrate |
| US6253704B1 (en) | 1995-10-13 | 2001-07-03 | Mattson Technology, Inc. | Apparatus and method for pulsed plasma processing of a semiconductor substrate |
| US6794301B2 (en) | 1995-10-13 | 2004-09-21 | Mattson Technology, Inc. | Pulsed plasma processing of semiconductor substrates |
| US5983828A (en) * | 1995-10-13 | 1999-11-16 | Mattson Technology, Inc. | Apparatus and method for pulsed plasma processing of a semiconductor substrate |
| US5877090A (en) * | 1997-06-03 | 1999-03-02 | Applied Materials, Inc. | Selective plasma etching of silicon nitride in presence of silicon or silicon oxides using mixture of NH3 or SF6 and HBR and N2 |
| US6165375A (en) | 1997-09-23 | 2000-12-26 | Cypress Semiconductor Corporation | Plasma etching method |
| US6294102B1 (en) * | 1999-05-05 | 2001-09-25 | International Business Machines Corporation | Selective dry etch of a dielectric film |
| US6372634B1 (en) | 1999-06-15 | 2002-04-16 | Cypress Semiconductor Corp. | Plasma etch chemistry and method of improving etch control |
| US6322716B1 (en) | 1999-08-30 | 2001-11-27 | Cypress Semiconductor Corp. | Method for conditioning a plasma etch chamber |
| US7803639B2 (en) * | 2007-01-04 | 2010-09-28 | International Business Machines Corporation | Method of forming vertical contacts in integrated circuits |
| US8008095B2 (en) * | 2007-10-03 | 2011-08-30 | International Business Machines Corporation | Methods for fabricating contacts to pillar structures in integrated circuits |
| US8563225B2 (en) | 2008-05-23 | 2013-10-22 | International Business Machines Corporation | Forming a self-aligned hard mask for contact to a tunnel junction |
| JP5537324B2 (en) * | 2010-08-05 | 2014-07-02 | 株式会社東芝 | Manufacturing method of semiconductor device |
| JP7261159B2 (en) | 2017-06-08 | 2023-04-19 | 株式会社レゾナック | Etching method |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4211601A (en) * | 1978-07-31 | 1980-07-08 | Bell Telephone Laboratories, Incorporated | Device fabrication by plasma etching |
| US4208241A (en) * | 1978-07-31 | 1980-06-17 | Bell Telephone Laboratories, Incorporated | Device fabrication by plasma etching |
| US4226665A (en) * | 1978-07-31 | 1980-10-07 | Bell Telephone Laboratories, Incorporated | Device fabrication by plasma etching |
| NL8004005A (en) * | 1980-07-11 | 1982-02-01 | Philips Nv | METHOD FOR MANUFACTURING A SEMICONDUCTOR DEVICE |
| US4450042A (en) * | 1982-07-06 | 1984-05-22 | Texas Instruments Incorporated | Plasma etch chemistry for anisotropic etching of silicon |
-
1982
- 1982-11-16 NL NL8204437A patent/NL8204437A/en not_active Application Discontinuation
-
1983
- 1983-10-31 US US06/547,178 patent/US4717447A/en not_active Expired - Fee Related
- 1983-11-08 CA CA000440705A patent/CA1208810A/en not_active Expired
- 1983-11-10 EP EP83201609A patent/EP0109706B1/en not_active Expired
- 1983-11-10 DE DE8383201609T patent/DE3369600D1/en not_active Expired
- 1983-11-12 JP JP58211730A patent/JPS59100539A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| EP0109706B1 (en) | 1987-01-28 |
| EP0109706A1 (en) | 1984-05-30 |
| JPS59100539A (en) | 1984-06-09 |
| NL8204437A (en) | 1984-06-18 |
| US4717447A (en) | 1988-01-05 |
| JPH0527245B2 (en) | 1993-04-20 |
| DE3369600D1 (en) | 1987-03-05 |
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